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* block: add a new set_read_only methodChristoph Hellwig2024-03-261-0/+5
| | | | | | | | | | | | | [ Upstream commit e00adcadf3af7a8335026d71ab9f0e0a922191ac ] Add a new method to allow for driver-specific processing when setting or clearing the block device read-only state. This allows to replace the cumbersome and error-prone override of the whole ioctl implementation. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> Stable-dep-of: 9674f54e41ff ("md: Don't clear MD_CLOSING when the raid is about to stop") Signed-off-by: Sasha Levin <sashal@kernel.org>
* md: switch to ->check_events for media change notificationsChristoph Hellwig2024-03-261-7/+1
| | | | | | | | | | | | | | [ Upstream commit a564e23f0f99759f453dbefcb9160dec6d99df96 ] md is the last driver using the legacy media_changed method. Switch it over to (not so) new ->clear_events approach, which also removes the need for the ->revalidate_disk method. Signed-off-by: Christoph Hellwig <hch@lst.de> [axboe: remove unused 'bdops' variable in disk_clear_events()] Signed-off-by: Jens Axboe <axboe@kernel.dk> Stable-dep-of: 9674f54e41ff ("md: Don't clear MD_CLOSING when the raid is about to stop") Signed-off-by: Sasha Levin <sashal@kernel.org>
* block: sed-opal: handle empty atoms when parsing responseGreg Joyce2024-03-262-1/+6
| | | | | | | | | | | | | | | [ Upstream commit 5429c8de56f6b2bd8f537df3a1e04e67b9c04282 ] The SED Opal response parsing function response_parse() does not handle the case of an empty atom in the response. This causes the entry count to be too high and the response fails to be parsed. Recognizing, but ignoring, empty atoms allows response handling to succeed. Signed-off-by: Greg Joyce <gjoyce@linux.ibm.com> Link: https://lore.kernel.org/r/20240216210417.3526064-2-gjoyce@linux.ibm.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* blk-mq: fix IO hang from sbitmap wakeup raceMing Lei2024-02-231-0/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 5266caaf5660529e3da53004b8b7174cab6374ed ] In blk_mq_mark_tag_wait(), __add_wait_queue() may be re-ordered with the following blk_mq_get_driver_tag() in case of getting driver tag failure. Then in __sbitmap_queue_wake_up(), waitqueue_active() may not observe the added waiter in blk_mq_mark_tag_wait() and wake up nothing, meantime blk_mq_mark_tag_wait() can't get driver tag successfully. This issue can be reproduced by running the following test in loop, and fio hang can be observed in < 30min when running it on my test VM in laptop. modprobe -r scsi_debug modprobe scsi_debug delay=0 dev_size_mb=4096 max_queue=1 host_max_queue=1 submit_queues=4 dev=`ls -d /sys/bus/pseudo/drivers/scsi_debug/adapter*/host*/target*/*/block/* | head -1 | xargs basename` fio --filename=/dev/"$dev" --direct=1 --rw=randrw --bs=4k --iodepth=1 \ --runtime=100 --numjobs=40 --time_based --name=test \ --ioengine=libaio Fix the issue by adding one explicit barrier in blk_mq_mark_tag_wait(), which is just fine in case of running out of tag. Cc: Jan Kara <jack@suse.cz> Cc: Kemeng Shi <shikemeng@huaweicloud.com> Reported-by: Changhui Zhong <czhong@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20240112122626.4181044-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* block: Remove special-casing of compound pagesMatthew Wilcox (Oracle)2024-02-231-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 1b151e2435fc3a9b10c8946c6aebe9f3e1938c55 upstream. The special casing was originally added in pre-git history; reproducing the commit log here: > commit a318a92567d77 > Author: Andrew Morton <akpm@osdl.org> > Date: Sun Sep 21 01:42:22 2003 -0700 > > [PATCH] Speed up direct-io hugetlbpage handling > > This patch short-circuits all the direct-io page dirtying logic for > higher-order pages. Without this, we pointlessly bounce BIOs up to > keventd all the time. In the last twenty years, compound pages have become used for more than just hugetlb. Rewrite these functions to operate on folios instead of pages and remove the special case for hugetlbfs; I don't think it's needed any more (and if it is, we can put it back in as a call to folio_test_hugetlb()). This was found by inspection; as far as I can tell, this bug can lead to pages used as the destination of a direct I/O read not being marked as dirty. If those pages are then reclaimed by the MM without being dirtied for some other reason, they won't be written out. Then when they're faulted back in, they will not contain the data they should. It'll take a pretty unusual setup to produce this problem with several races all going the wrong way. This problem predates the folio work; it could for example have been triggered by mmaping a THP in tmpfs and using that as the target of an O_DIRECT read. Fixes: 800d8c63b2e98 ("shmem: add huge pages support") Cc: <stable@vger.kernel.org> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* blk-throttle: fix lockdep warning of "cgroup_mutex or RCU read lock required!"Ming Lei2023-12-201-0/+2
| | | | | | | | | | | | | | | | | [ Upstream commit 27b13e209ddca5979847a1b57890e0372c1edcee ] Inside blkg_for_each_descendant_pre(), both css_for_each_descendant_pre() and blkg_lookup() requires RCU read lock, and either cgroup_assert_mutex_or_rcu_locked() or rcu_read_lock_held() is called. Fix the warning by adding rcu read lock. Reported-by: Changhui Zhong <czhong@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20231117023527.3188627-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* block: fix signed int overflow in Amiga partition supportMichael Schmitz2023-08-301-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit fc3d092c6bb48d5865fec15ed5b333c12f36288c ] The Amiga partition parser module uses signed int for partition sector address and count, which will overflow for disks larger than 1 TB. Use sector_t as type for sector address and size to allow using disks up to 2 TB without LBD support, and disks larger than 2 TB with LBD. This bug was reported originally in 2012, and the fix was created by the RDB author, Joanne Dow <jdow@earthlink.net>. A patch had been discussed and reviewed on linux-m68k at that time but never officially submitted. This patch differs from Joanne's patch only in its use of sector_t instead of unsigned int. No checking for overflows is done (see patch 3 of this series for that). Reported-by: Martin Steigerwald <Martin@lichtvoll.de> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=43511 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Message-ID: <201206192146.09327.Martin@lichtvoll.de> Cc: <stable@vger.kernel.org> # 5.2 Signed-off-by: Michael Schmitz <schmitzmic@gmail.com> Tested-by: Martin Steigerwald <Martin@lichtvoll.de> Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230620201725.7020-2-schmitzmic@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* block: bio-integrity: Copy flags when bio_integrity_payload is clonedMartin K. Petersen2023-03-111-0/+1
| | | | | | | | | | | | | | | | | | | | | [ Upstream commit b6a4bdcda430e3ca43bbb9cb1d4d4d34ebe15c40 ] Make sure to copy the flags when a bio_integrity_payload is cloned. Otherwise per-I/O properties such as IP checksum flag will not be passed down to the HBA driver. Since the integrity buffer is owned by the original bio, the BIP_BLOCK_INTEGRITY flag needs to be masked off to avoid a double free in the completion path. Fixes: aae7df50190a ("block: Integrity checksum flag") Fixes: b1f01388574c ("block: Relocate bio integrity flags") Reported-by: Saurav Kashyap <skashyap@marvell.com> Tested-by: Saurav Kashyap <skashyap@marvell.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Link: https://lore.kernel.org/r/20230215171801.21062-1-martin.petersen@oracle.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* blk-mq: remove stale comment for blk_mq_sched_mark_restart_hctxKemeng Shi2023-03-111-2/+1
| | | | | | | | | | | | | | | | [ Upstream commit c31e76bcc379182fe67a82c618493b7b8868c672 ] Commit 97889f9ac24f8 ("blk-mq: remove synchronize_rcu() from blk_mq_del_queue_tag_set()") remove handle of TAG_SHARED in restart, then shared_hctx_restart counted for how many hardware queues are marked for restart is removed too. Remove the stale comment that we still count hardware queues need restart. Fixes: 97889f9ac24f ("blk-mq: remove synchronize_rcu() from blk_mq_del_queue_tag_set()") Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* block: fix and cleanup bio_check_roChristoph Hellwig2023-02-061-4/+1
| | | | | | | | | | | | | | | | | commit 57e95e4670d1126c103305bcf34a9442f49f6d6a upstream. Don't use a WARN_ON when printing a potentially user triggered condition. Also don't print the partno when the block device name already includes it, and use the %pg specifier to simplify printing the block device name. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Link: https://lore.kernel.org/r/20220304180105.409765-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* blk-mq: fix possible memleak when register 'hctx' failedYe Bin2023-01-181-2/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 4b7a21c57b14fbcd0e1729150189e5933f5088e9 ] There's issue as follows when do fault injection test: unreferenced object 0xffff888132a9f400 (size 512): comm "insmod", pid 308021, jiffies 4324277909 (age 509.733s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 08 f4 a9 32 81 88 ff ff ...........2.... 08 f4 a9 32 81 88 ff ff 00 00 00 00 00 00 00 00 ...2............ backtrace: [<00000000e8952bb4>] kmalloc_node_trace+0x22/0xa0 [<00000000f9980e0f>] blk_mq_alloc_and_init_hctx+0x3f1/0x7e0 [<000000002e719efa>] blk_mq_realloc_hw_ctxs+0x1e6/0x230 [<000000004f1fda40>] blk_mq_init_allocated_queue+0x27e/0x910 [<00000000287123ec>] __blk_mq_alloc_disk+0x67/0xf0 [<00000000a2a34657>] 0xffffffffa2ad310f [<00000000b173f718>] 0xffffffffa2af824a [<0000000095a1dabb>] do_one_initcall+0x87/0x2a0 [<00000000f32fdf93>] do_init_module+0xdf/0x320 [<00000000cbe8541e>] load_module+0x3006/0x3390 [<0000000069ed1bdb>] __do_sys_finit_module+0x113/0x1b0 [<00000000a1a29ae8>] do_syscall_64+0x35/0x80 [<000000009cd878b0>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 Fault injection context as follows: kobject_add blk_mq_register_hctx blk_mq_sysfs_register blk_register_queue device_add_disk null_add_dev.part.0 [null_blk] As 'blk_mq_register_hctx' may already add some objects when failed halfway, but there isn't do fallback, caller don't know which objects add failed. To solve above issue just do fallback when add objects failed halfway in 'blk_mq_register_hctx'. Signed-off-by: Ye Bin <yebin10@huawei.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20221117022940.873959-1-yebin@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* block: unhash blkdev part inode when the part is deletedMing Lei2023-01-181-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | v5.11 changes the blkdev lookup mechanism completely since commit 22ae8ce8b892 ("block: simplify bdev/disk lookup in blkdev_get"), and small part of the change is to unhash part bdev inode when deleting partition. Turns out this kind of change does fix one nasty issue in case of BLOCK_EXT_MAJOR: 1) when one partition is deleted & closed, disk_put_part() is always called before bdput(bdev), see blkdev_put(); so the part's devt can be freed & re-used before the inode is dropped 2) then new partition with same devt can be created just before the inode in 1) is dropped, then the old inode/bdev structurein 1) is re-used for this new partition, this way causes use-after-free and kernel panic. It isn't possible to backport the whole big patchset of "merge struct block_device and struct hd_struct v4" for addressing this issue. https://lore.kernel.org/linux-block/20201128161510.347752-1-hch@lst.de/ So fixes it by unhashing part bdev in delete_partition(), and this way is actually aligned with v5.11+'s behavior. Backported from the following 5.10.y commit: 5f2f77560591 ("block: unhash blkdev part inode when the part is deleted") Reported-by: Shiwei Cui <cuishw@inspur.com> Tested-by: Shiwei Cui <cuishw@inspur.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* block: sed-opal: kmalloc the cmd/resp buffersSerge Semin2022-11-251-4/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit f829230dd51974c1f4478900ed30bb77ba530b40 ] In accordance with [1] the DMA-able memory buffers must be cacheline-aligned otherwise the cache writing-back and invalidation performed during the mapping may cause the adjacent data being lost. It's specifically required for the DMA-noncoherent platforms [2]. Seeing the opal_dev.{cmd,resp} buffers are implicitly used for DMAs in the NVME and SCSI/SD drivers in framework of the nvme_sec_submit() and sd_sec_submit() methods respectively they must be cacheline-aligned to prevent the denoted problem. One of the option to guarantee that is to kmalloc the buffers [2]. Let's explicitly allocate them then instead of embedding into the opal_dev structure instance. Note this fix was inspired by the commit c94b7f9bab22 ("nvme-hwmon: kmalloc the NVME SMART log buffer"). [1] Documentation/core-api/dma-api.rst [2] Documentation/core-api/dma-api-howto.rst Fixes: 455a7b238cd6 ("block: Add Sed-opal library") Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20221107203944.31686-1-Sergey.Semin@baikalelectronics.ru Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* block, bfq: protect 'bfqd->queued' by 'bfqd->lock'Yu Kuai2022-11-101-1/+3
| | | | | | | | | | | | | | | | | | commit 181490d5321806e537dc5386db5ea640b826bf78 upstream. If bfq_schedule_dispatch() is called from bfq_idle_slice_timer_body(), then 'bfqd->queued' is read without holding 'bfqd->lock'. This is wrong since it can be wrote concurrently. Fix the problem by holding 'bfqd->lock' in such case. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Link: https://lore.kernel.org/r/20220513023507.2625717-2-yukuai3@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Cc: Khazhy Kumykov <khazhy@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* blk-iolatency: Fix inflight count imbalances and IO hangs on offlineTejun Heo2022-06-141-58/+64
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 8a177a36da6c54c98b8685d4f914cb3637d53c0d upstream. iolatency needs to track the number of inflight IOs per cgroup. As this tracking can be expensive, it is disabled when no cgroup has iolatency configured for the device. To ensure that the inflight counters stay balanced, iolatency_set_limit() freezes the request_queue while manipulating the enabled counter, which ensures that no IO is in flight and thus all counters are zero. Unfortunately, iolatency_set_limit() isn't the only place where the enabled counter is manipulated. iolatency_pd_offline() can also dec the counter and trigger disabling. As this disabling happens without freezing the q, this can easily happen while some IOs are in flight and thus leak the counts. This can be easily demonstrated by turning on iolatency on an one empty cgroup while IOs are in flight in other cgroups and then removing the cgroup. Note that iolatency shouldn't have been enabled elsewhere in the system to ensure that removing the cgroup disables iolatency for the whole device. The following keeps flipping on and off iolatency on sda: echo +io > /sys/fs/cgroup/cgroup.subtree_control while true; do mkdir -p /sys/fs/cgroup/test echo '8:0 target=100000' > /sys/fs/cgroup/test/io.latency sleep 1 rmdir /sys/fs/cgroup/test sleep 1 done and there's concurrent fio generating direct rand reads: fio --name test --filename=/dev/sda --direct=1 --rw=randread \ --runtime=600 --time_based --iodepth=256 --numjobs=4 --bs=4k while monitoring with the following drgn script: while True: for css in css_for_each_descendant_pre(prog['blkcg_root'].css.address_of_()): for pos in hlist_for_each(container_of(css, 'struct blkcg', 'css').blkg_list): blkg = container_of(pos, 'struct blkcg_gq', 'blkcg_node') pd = blkg.pd[prog['blkcg_policy_iolatency'].plid] if pd.value_() == 0: continue iolat = container_of(pd, 'struct iolatency_grp', 'pd') inflight = iolat.rq_wait.inflight.counter.value_() if inflight: print(f'inflight={inflight} {disk_name(blkg.q.disk).decode("utf-8")} ' f'{cgroup_path(css.cgroup).decode("utf-8")}') time.sleep(1) The monitoring output looks like the following: inflight=1 sda /user.slice inflight=1 sda /user.slice ... inflight=14 sda /user.slice inflight=13 sda /user.slice inflight=17 sda /user.slice inflight=15 sda /user.slice inflight=18 sda /user.slice inflight=17 sda /user.slice inflight=20 sda /user.slice inflight=19 sda /user.slice <- fio stopped, inflight stuck at 19 inflight=19 sda /user.slice inflight=19 sda /user.slice If a cgroup with stuck inflight ends up getting throttled, the throttled IOs will never get issued as there's no completion event to wake it up leading to an indefinite hang. This patch fixes the bug by unifying enable handling into a work item which is automatically kicked off from iolatency_set_min_lat_nsec() which is called from both iolatency_set_limit() and iolatency_pd_offline() paths. Punting to a work item is necessary as iolatency_pd_offline() is called under spinlocks while freezing a request_queue requires a sleepable context. This also simplifies the code reducing LOC sans the comments and avoids the unnecessary freezes which were happening whenever a cgroup's latency target is newly set or cleared. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Liu Bo <bo.liu@linux.alibaba.com> Fixes: 8c772a9bfc7c ("blk-iolatency: fix IO hang due to negative inflight counter") Cc: stable@vger.kernel.org # v5.0+ Link: https://lore.kernel.org/r/Yn9ScX6Nx2qIiQQi@slm.duckdns.org Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* block-map: add __GFP_ZERO flag for alloc_page in function bio_copy_kernHaimin Zhang2022-06-061-1/+1
| | | | | | | | | | | | | | | | commit cc8f7fe1f5eab010191aa4570f27641876fa1267 upstream. Add __GFP_ZERO flag for alloc_page in function bio_copy_kern to initialize the buffer of a bio. Signed-off-by: Haimin Zhang <tcs.kernel@gmail.com> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20220216084038.15635-1-tcs.kernel@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> [DP: Backported to 4.19: Manually added __GFP_ZERO flag] Signed-off-by: Dragos-Marian Panait <dragos.panait@windriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* block/compat_ioctl: fix range check in BLKGETSIZEKhazhismel Kumykov2022-04-271-1/+1
| | | | | | | | | | | | | | | | | commit ccf16413e520164eb718cf8b22a30438da80ff23 upstream. kernel ulong and compat_ulong_t may not be same width. Use type directly to eliminate mismatches. This would result in truncation rather than EFBIG for 32bit mode for large disks. Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Khazhismel Kumykov <khazhy@google.com> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Link: https://lore.kernel.org/r/20220414224056.2875681-1-khazhy@google.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "Revert "block, bfq: honor already-setup queue merges""Paolo Valente2022-04-151-3/+13
| | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 15729ff8143f8135b03988a100a19e66d7cb7ecd ] A crash [1] happened to be triggered in conjunction with commit 2d52c58b9c9b ("block, bfq: honor already-setup queue merges"). The latter was then reverted by commit ebc69e897e17 ("Revert "block, bfq: honor already-setup queue merges""). Yet, the reverted commit was not the one introducing the bug. In fact, it actually triggered a UAF introduced by a different commit, and now fixed by commit d29bd41428cf ("block, bfq: reset last_bfqq_created on group change"). So, there is no point in keeping commit 2d52c58b9c9b ("block, bfq: honor already-setup queue merges") out. This commit restores it. [1] https://bugzilla.kernel.org/show_bug.cgi?id=214503 Reported-by: Holger Hoffstätte <holger@applied-asynchrony.com> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Link: https://lore.kernel.org/r/20211125181510.15004-1-paolo.valente@linaro.org Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* bfq: fix use-after-free in bfq_dispatch_requestZhang Wensheng2022-04-151-7/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit ab552fcb17cc9e4afe0e4ac4df95fc7b30e8490a ] KASAN reports a use-after-free report when doing normal scsi-mq test [69832.239032] ================================================================== [69832.241810] BUG: KASAN: use-after-free in bfq_dispatch_request+0x1045/0x44b0 [69832.243267] Read of size 8 at addr ffff88802622ba88 by task kworker/3:1H/155 [69832.244656] [69832.245007] CPU: 3 PID: 155 Comm: kworker/3:1H Not tainted 5.10.0-10295-g576c6382529e #8 [69832.246626] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [69832.249069] Workqueue: kblockd blk_mq_run_work_fn [69832.250022] Call Trace: [69832.250541] dump_stack+0x9b/0xce [69832.251232] ? bfq_dispatch_request+0x1045/0x44b0 [69832.252243] print_address_description.constprop.6+0x3e/0x60 [69832.253381] ? __cpuidle_text_end+0x5/0x5 [69832.254211] ? vprintk_func+0x6b/0x120 [69832.254994] ? bfq_dispatch_request+0x1045/0x44b0 [69832.255952] ? bfq_dispatch_request+0x1045/0x44b0 [69832.256914] kasan_report.cold.9+0x22/0x3a [69832.257753] ? bfq_dispatch_request+0x1045/0x44b0 [69832.258755] check_memory_region+0x1c1/0x1e0 [69832.260248] bfq_dispatch_request+0x1045/0x44b0 [69832.261181] ? bfq_bfqq_expire+0x2440/0x2440 [69832.262032] ? blk_mq_delay_run_hw_queues+0xf9/0x170 [69832.263022] __blk_mq_do_dispatch_sched+0x52f/0x830 [69832.264011] ? blk_mq_sched_request_inserted+0x100/0x100 [69832.265101] __blk_mq_sched_dispatch_requests+0x398/0x4f0 [69832.266206] ? blk_mq_do_dispatch_ctx+0x570/0x570 [69832.267147] ? __switch_to+0x5f4/0xee0 [69832.267898] blk_mq_sched_dispatch_requests+0xdf/0x140 [69832.268946] __blk_mq_run_hw_queue+0xc0/0x270 [69832.269840] blk_mq_run_work_fn+0x51/0x60 [69832.278170] process_one_work+0x6d4/0xfe0 [69832.278984] worker_thread+0x91/0xc80 [69832.279726] ? __kthread_parkme+0xb0/0x110 [69832.280554] ? process_one_work+0xfe0/0xfe0 [69832.281414] kthread+0x32d/0x3f0 [69832.282082] ? kthread_park+0x170/0x170 [69832.282849] ret_from_fork+0x1f/0x30 [69832.283573] [69832.283886] Allocated by task 7725: [69832.284599] kasan_save_stack+0x19/0x40 [69832.285385] __kasan_kmalloc.constprop.2+0xc1/0xd0 [69832.286350] kmem_cache_alloc_node+0x13f/0x460 [69832.287237] bfq_get_queue+0x3d4/0x1140 [69832.287993] bfq_get_bfqq_handle_split+0x103/0x510 [69832.289015] bfq_init_rq+0x337/0x2d50 [69832.289749] bfq_insert_requests+0x304/0x4e10 [69832.290634] blk_mq_sched_insert_requests+0x13e/0x390 [69832.291629] blk_mq_flush_plug_list+0x4b4/0x760 [69832.292538] blk_flush_plug_list+0x2c5/0x480 [69832.293392] io_schedule_prepare+0xb2/0xd0 [69832.294209] io_schedule_timeout+0x13/0x80 [69832.295014] wait_for_common_io.constprop.1+0x13c/0x270 [69832.296137] submit_bio_wait+0x103/0x1a0 [69832.296932] blkdev_issue_discard+0xe6/0x160 [69832.297794] blk_ioctl_discard+0x219/0x290 [69832.298614] blkdev_common_ioctl+0x50a/0x1750 [69832.304715] blkdev_ioctl+0x470/0x600 [69832.305474] block_ioctl+0xde/0x120 [69832.306232] vfs_ioctl+0x6c/0xc0 [69832.306877] __se_sys_ioctl+0x90/0xa0 [69832.307629] do_syscall_64+0x2d/0x40 [69832.308362] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [69832.309382] [69832.309701] Freed by task 155: [69832.310328] kasan_save_stack+0x19/0x40 [69832.311121] kasan_set_track+0x1c/0x30 [69832.311868] kasan_set_free_info+0x1b/0x30 [69832.312699] __kasan_slab_free+0x111/0x160 [69832.313524] kmem_cache_free+0x94/0x460 [69832.314367] bfq_put_queue+0x582/0x940 [69832.315112] __bfq_bfqd_reset_in_service+0x166/0x1d0 [69832.317275] bfq_bfqq_expire+0xb27/0x2440 [69832.318084] bfq_dispatch_request+0x697/0x44b0 [69832.318991] __blk_mq_do_dispatch_sched+0x52f/0x830 [69832.319984] __blk_mq_sched_dispatch_requests+0x398/0x4f0 [69832.321087] blk_mq_sched_dispatch_requests+0xdf/0x140 [69832.322225] __blk_mq_run_hw_queue+0xc0/0x270 [69832.323114] blk_mq_run_work_fn+0x51/0x60 [69832.323942] process_one_work+0x6d4/0xfe0 [69832.324772] worker_thread+0x91/0xc80 [69832.325518] kthread+0x32d/0x3f0 [69832.326205] ret_from_fork+0x1f/0x30 [69832.326932] [69832.338297] The buggy address belongs to the object at ffff88802622b968 [69832.338297] which belongs to the cache bfq_queue of size 512 [69832.340766] The buggy address is located 288 bytes inside of [69832.340766] 512-byte region [ffff88802622b968, ffff88802622bb68) [69832.343091] The buggy address belongs to the page: [69832.344097] page:ffffea0000988a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88802622a528 pfn:0x26228 [69832.346214] head:ffffea0000988a00 order:2 compound_mapcount:0 compound_pincount:0 [69832.347719] flags: 0x1fffff80010200(slab|head) [69832.348625] raw: 001fffff80010200 ffffea0000dbac08 ffff888017a57650 ffff8880179fe840 [69832.354972] raw: ffff88802622a528 0000000000120008 00000001ffffffff 0000000000000000 [69832.356547] page dumped because: kasan: bad access detected [69832.357652] [69832.357970] Memory state around the buggy address: [69832.358926] ffff88802622b980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [69832.360358] ffff88802622ba00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [69832.361810] >ffff88802622ba80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [69832.363273] ^ [69832.363975] ffff88802622bb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc [69832.375960] ffff88802622bb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [69832.377405] ================================================================== In bfq_dispatch_requestfunction, it may have function call: bfq_dispatch_request __bfq_dispatch_request bfq_select_queue bfq_bfqq_expire __bfq_bfqd_reset_in_service bfq_put_queue kmem_cache_free In this function call, in_serv_queue has beed expired and meet the conditions to free. In the function bfq_dispatch_request, the address of in_serv_queue pointing to has been released. For getting the value of idle_timer_disabled, it will get flags value from the address which in_serv_queue pointing to, then the problem of use-after-free happens; Fix the problem by check in_serv_queue == bfqd->in_service_queue, to get the value of idle_timer_disabled if in_serve_queue is equel to bfqd->in_service_queue. If the space of in_serv_queue pointing has been released, this judge will aviod use-after-free problem. And if in_serv_queue may be expired or finished, the idle_timer_disabled will be false which would not give effects to bfq_update_dispatch_stats. Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Zhang Wensheng <zhangwensheng5@huawei.com> Link: https://lore.kernel.org/r/20220303070334.3020168-1-zhangwensheng5@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* block: don't delete queue kobject before its childrenEric Biggers2022-04-151-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 0f69288253e9fc7c495047720e523b9f1aba5712 ] kobjects aren't supposed to be deleted before their child kobjects are deleted. Apparently this is usually benign; however, a WARN will be triggered if one of the child kobjects has a named attribute group: sysfs group 'modes' not found for kobject 'crypto' WARNING: CPU: 0 PID: 1 at fs/sysfs/group.c:278 sysfs_remove_group+0x72/0x80 ... Call Trace: sysfs_remove_groups+0x29/0x40 fs/sysfs/group.c:312 __kobject_del+0x20/0x80 lib/kobject.c:611 kobject_cleanup+0xa4/0x140 lib/kobject.c:696 kobject_release lib/kobject.c:736 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x53/0x70 lib/kobject.c:753 blk_crypto_sysfs_unregister+0x10/0x20 block/blk-crypto-sysfs.c:159 blk_unregister_queue+0xb0/0x110 block/blk-sysfs.c:962 del_gendisk+0x117/0x250 block/genhd.c:610 Fix this by moving the kobject_del() and the corresponding kobject_uevent() to the correct place. Fixes: 2c2086afc2b8 ("block: Protect less code with sysfs_lock in blk_{un,}register_queue()") Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20220124215938.2769-3-ebiggers@kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* block: don't merge across cgroup boundaries if blkcg is enabledTejun Heo2022-04-151-0/+12
| | | | | | | | | | | | | | | | | | | | | | commit 6b2b04590b51aa4cf395fcd185ce439cab5961dc upstream. blk-iocost and iolatency are cgroup aware rq-qos policies but they didn't disable merges across different cgroups. This obviously can lead to accounting and control errors but more importantly to priority inversions - e.g. an IO which belongs to a higher priority cgroup or IO class may end up getting throttled incorrectly because it gets merged to an IO issued from a low priority cgroup. Fix it by adding blk_cgroup_mergeable() which is called from merge paths and rejects cross-cgroup and cross-issue_as_root merges. Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: d70675121546 ("block: introduce blk-iolatency io controller") Cc: stable@vger.kernel.org # v4.19+ Cc: Josef Bacik <jbacik@fb.com> Link: https://lore.kernel.org/r/Yi/eE/6zFNyWJ+qd@slm.duckdns.org Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* block: Fix fsync always failed if once failedYe Bin2022-03-081-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 8a7518931baa8ea023700987f3db31cb0a80610b upstream. We do test with inject error fault base on v4.19, after test some time we found sync /dev/sda always failed. [root@localhost] sync /dev/sda sync: error syncing '/dev/sda': Input/output error scsi log as follows: [19069.812296] sd 0:0:0:0: [sda] tag#64 Send: scmd 0x00000000d03a0b6b [19069.812302] sd 0:0:0:0: [sda] tag#64 CDB: Synchronize Cache(10) 35 00 00 00 00 00 00 00 00 00 [19069.812533] sd 0:0:0:0: [sda] tag#64 Done: SUCCESS Result: hostbyte=DID_OK driverbyte=DRIVER_OK [19069.812536] sd 0:0:0:0: [sda] tag#64 CDB: Synchronize Cache(10) 35 00 00 00 00 00 00 00 00 00 [19069.812539] sd 0:0:0:0: [sda] tag#64 scsi host busy 1 failed 0 [19069.812542] sd 0:0:0:0: Notifying upper driver of completion (result 0) [19069.812546] sd 0:0:0:0: [sda] tag#64 sd_done: completed 0 of 0 bytes [19069.812549] sd 0:0:0:0: [sda] tag#64 0 sectors total, 0 bytes done. [19069.812564] print_req_error: I/O error, dev sda, sector 0 ftrace log as follows: rep-306069 [007] .... 19654.923315: block_bio_queue: 8,0 FWS 0 + 0 [rep] rep-306069 [007] .... 19654.923333: block_getrq: 8,0 FWS 0 + 0 [rep] kworker/7:1H-250 [007] .... 19654.923352: block_rq_issue: 8,0 FF 0 () 0 + 0 [kworker/7:1H] <idle>-0 [007] ..s. 19654.923562: block_rq_complete: 8,0 FF () 18446744073709551615 + 0 [0] <idle>-0 [007] d.s. 19654.923576: block_rq_complete: 8,0 WS () 0 + 0 [-5] As 8d6996630c03 introduce 'fq->rq_status', this data only update when 'flush_rq' reference count isn't zero. If flush request once failed and record error code in 'fq->rq_status'. If there is no chance to update 'fq->rq_status',then do fsync will always failed. To address this issue reset 'fq->rq_status' after return error code to upper layer. Fixes: 8d6996630c03("block: fix null pointer dereference in blk_mq_rq_timed_out()") Signed-off-by: Ye Bin <yebin10@huawei.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20211129012659.1553733-1-yebin10@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk> [sudip: adjust context] Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* block/wbt: fix negative inflight counter when remove scsi deviceLaibin Qiu2022-02-232-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit e92bc4cd34de2ce454bdea8cd198b8067ee4e123 upstream. Now that we disable wbt by set WBT_STATE_OFF_DEFAULT in wbt_disable_default() when switch elevator to bfq. And when we remove scsi device, wbt will be enabled by wbt_enable_default. If it become false positive between wbt_wait() and wbt_track() when submit write request. The following is the scenario that triggered the problem. T1 T2 T3 elevator_switch_mq bfq_init_queue wbt_disable_default <= Set rwb->enable_state (OFF) Submit_bio blk_mq_make_request rq_qos_throttle <= rwb->enable_state (OFF) scsi_remove_device sd_remove del_gendisk blk_unregister_queue elv_unregister_queue wbt_enable_default <= Set rwb->enable_state (ON) q_qos_track <= rwb->enable_state (ON) ^^^^^^ this request will mark WBT_TRACKED without inflight add and will lead to drop rqw->inflight to -1 in wbt_done() which will trigger IO hung. Fix this by move wbt_enable_default() from elv_unregister to bfq_exit_queue(). Only re-enable wbt when bfq exit. Fixes: 76a8040817b4b ("blk-wbt: make sure throttle is enabled properly") Remove oneline stale comment, and kill one oneshot local variable. Signed-off-by: Ming Lei <ming.lei@rehdat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/linux-block/20211214133103.551813-1-qiulaibin@huawei.com/ Signed-off-by: Laibin Qiu <qiulaibin@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* block: bio-integrity: Advance seed correctly for larger interval sizesMartin K. Petersen2022-02-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | commit b13e0c71856817fca67159b11abac350e41289f5 upstream. Commit 309a62fa3a9e ("bio-integrity: bio_integrity_advance must update integrity seed") added code to update the integrity seed value when advancing a bio. However, it failed to take into account that the integrity interval might be larger than the 512-byte block layer sector size. This broke bio splitting on PI devices with 4KB logical blocks. The seed value should be advanced by bio_integrity_intervals() and not the number of sectors. Cc: Dmitry Monakhov <dmonakhov@openvz.org> Cc: stable@vger.kernel.org Fixes: 309a62fa3a9e ("bio-integrity: bio_integrity_advance must update integrity seed") Tested-by: Dmitry Ivanov <dmitry.ivanov2@hpe.com> Reported-by: Alexey Lyashkov <alexey.lyashkov@hpe.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Link: https://lore.kernel.org/r/20220204034209.4193-1-martin.petersen@oracle.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* block, bfq: fix use after free in bfq_bfqq_expirePaolo Valente2021-12-293-11/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit eed47d19d9362bdd958e4ab56af480b9dbf6b2b6 upstream. The function bfq_bfqq_expire() invokes the function __bfq_bfqq_expire(), and the latter may free the in-service bfq-queue. If this happens, then no other instruction of bfq_bfqq_expire() must be executed, or a use-after-free will occur. Basing on the assumption that __bfq_bfqq_expire() invokes bfq_put_queue() on the in-service bfq-queue exactly once, the queue is assumed to be freed if its refcounter is equal to one right before invoking __bfq_bfqq_expire(). But, since commit 9dee8b3b057e ("block, bfq: fix queue removal from weights tree") this assumption is false. __bfq_bfqq_expire() may also invoke bfq_weights_tree_remove() and, since commit 9dee8b3b057e ("block, bfq: fix queue removal from weights tree"), also the latter function may invoke bfq_put_queue(). So __bfq_bfqq_expire() may invoke bfq_put_queue() twice, and this is the actual case where the in-service queue may happen to be freed. To address this issue, this commit moves the check on the refcounter of the queue right around the last bfq_put_queue() that may be invoked on the queue. Fixes: 9dee8b3b057e ("block, bfq: fix queue removal from weights tree") Reported-by: Dmitrii Tcvetkov <demfloro@demfloro.ru> Reported-by: Douglas Anderson <dianders@chromium.org> Tested-by: Dmitrii Tcvetkov <demfloro@demfloro.ru> Tested-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Yu Kuai <yukuai3@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* block, bfq: fix queue removal from weights treePaolo Valente2021-12-292-7/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 9dee8b3b057e1da26f85f1842f2aaf3bb200fb94 upstream. bfq maintains an ordered list, through a red-black tree, of unique weights of active bfq_queues. This list is used to detect whether there are active queues with differentiated weights. The weight of a queue is removed from the list when both the following two conditions become true: (1) the bfq_queue is flagged as inactive (2) the has no in-flight request any longer; Unfortunately, in the rare cases where condition (2) becomes true before condition (1), the removal fails, because the function to remove the weight of the queue (bfq_weights_tree_remove) is rightly invoked in the path that deactivates the bfq_queue, but mistakenly invoked *before* the function that actually performs the deactivation (bfq_deactivate_bfqq). This commits moves the invocation of bfq_weights_tree_remove for condition (1) to after bfq_deactivate_bfqq. As a consequence of this move, it is necessary to add a further reference to the queue when the weight of a queue is added, because the queue might otherwise be freed before bfq_weights_tree_remove is invoked. This commit adds this reference and makes all related modifications. Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Yu Kuai <yukuai3@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* block, bfq: fix decrement of num_active_groupsPaolo Valente2021-12-293-25/+107
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit ba7aeae5539c7a7cccc4cf07a2bc61281a93c50e upstream. Since commit '2d29c9f89fcd ("block, bfq: improve asymmetric scenarios detection")', if there are process groups with I/O requests waiting for completion, then BFQ tags the scenario as 'asymmetric'. This detection is needed for preserving service guarantees (for details, see comments on the computation * of the variable asymmetric_scenario in the function bfq_better_to_idle). Unfortunately, commit '2d29c9f89fcd ("block, bfq: improve asymmetric scenarios detection")' contains an error exactly in the updating of the number of groups with I/O requests waiting for completion: if a group has more than one descendant process, then the above number of groups, which is renamed from num_active_groups to a more appropriate num_groups_with_pending_reqs by this commit, may happen to be wrongly decremented multiple times, namely every time one of the descendant processes gets all its pending I/O requests completed. A correct, complete solution should work as follows. Consider a group that is inactive, i.e., that has no descendant process with pending I/O inside BFQ queues. Then suppose that num_groups_with_pending_reqs is still accounting for this group, because the group still has some descendant process with some I/O request still in flight. num_groups_with_pending_reqs should be decremented when the in-flight request of the last descendant process is finally completed (assuming that nothing else has changed for the group in the meantime, in terms of composition of the group and active/inactive state of child groups and processes). To accomplish this, an additional pending-request counter must be added to entities, and must be updated correctly. To avoid this additional field and operations, this commit resorts to the following tradeoff between simplicity and accuracy: for an inactive group that is still counted in num_groups_with_pending_reqs, this commit decrements num_groups_with_pending_reqs when the first descendant process of the group remains with no request waiting for completion. This simplified scheme provides a fix to the unbalanced decrements introduced by 2d29c9f89fcd. Since this error was also caused by lack of comments on this non-trivial issue, this commit also adds related comments. Fixes: 2d29c9f89fcd ("block, bfq: improve asymmetric scenarios detection") Reported-by: Steven Barrett <steven@liquorix.net> Tested-by: Steven Barrett <steven@liquorix.net> Tested-by: Lucjan Lucjanov <lucjan.lucjanov@gmail.com> Reviewed-by: Federico Motta <federico@willer.it> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Yu Kuai <yukuai3@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* block, bfq: fix asymmetric scenarios detectionFederico Motta2021-12-291-12/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 98fa7a3e001b21fb47c08af4304f40a3b0535cbd upstream. Since commit 2d29c9f89fcd ("block, bfq: improve asymmetric scenarios detection"), a scenario is defined asymmetric when one of the following conditions holds: - active bfq_queues have different weights - one or more group of entities (bfq_queue or other groups of entities) are active bfq grants fairness and low latency also in such asymmetric scenarios, by plugging the dispatching of I/O if the bfq_queue in service happens to be temporarily idle. This plugging may lower throughput, so it is important to do it only when strictly needed. By mistake, in commit '2d29c9f89fcd' ("block, bfq: improve asymmetric scenarios detection") the num_active_groups counter was firstly incremented and subsequently decremented at any entity (group or bfq_queue) weight change. This is useless, because only transitions from active to inactive and vice versa matter for that counter. Unfortunately this is also incorrect in the following case: the entity at issue is a bfq_queue and it is under weight raising. In fact in this case there is a spurious increment of the num_active_groups counter. This spurious increment may cause scenarios to be wrongly detected as asymmetric, thus causing useless plugging and loss of throughput. This commit fixes this issue by simply removing the above useless and wrong increments and decrements. Fixes: 2d29c9f89fcd ("block, bfq: improve asymmetric scenarios detection") Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Signed-off-by: Federico Motta <federico@willer.it> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Yu Kuai <yukuai3@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* block, bfq: improve asymmetric scenarios detectionFederico Motta2021-12-293-131/+155
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 2d29c9f89fcd9bf408fcdaaf515c90a169f22ecd upstream. bfq defines as asymmetric a scenario where an active entity, say E (representing either a single bfq_queue or a group of other entities), has a higher weight than some other entities. If the entity E does sync I/O in such a scenario, then bfq plugs the dispatch of the I/O of the other entities in the following situation: E is in service but temporarily has no pending I/O request. In fact, without this plugging, all the times that E stops being temporarily idle, it may find the internal queues of the storage device already filled with an out-of-control number of extra requests, from other entities. So E may have to wait for the service of these extra requests, before finally having its own requests served. This may easily break service guarantees, with E getting less than its fair share of the device throughput. Usually, the end result is that E gets the same fraction of the throughput as the other entities, instead of getting more, according to its higher weight. Yet there are two other more subtle cases where E, even if its weight is actually equal to or even lower than the weight of any other active entities, may get less than its fair share of the throughput in case the above I/O plugging is not performed: 1. other entities issue larger requests than E; 2. other entities contain more active child entities than E (or in general tend to have more backlog than E). In the first case, other entities may get more service than E because they get larger requests, than those of E, served during the temporary idle periods of E. In the second case, other entities get more service because, by having many child entities, they have many requests ready for dispatching while E is temporarily idle. This commit addresses this issue by extending the definition of asymmetric scenario: a scenario is asymmetric when - active entities representing bfq_queues have differentiated weights, as in the original definition or (inclusive) - one or more entities representing groups of entities are active. This broader definition makes sure that I/O plugging will be performed in all the above cases, provided that there is at least one active group. Of course, this definition is very coarse, so it will trigger I/O plugging also in cases where it is not needed, such as, e.g., multiple active entities with just one child each, and all with the same I/O-request size. The reason for this coarse definition is just that a finer-grained definition would be rather heavy to compute. On the opposite end, even this new definition does not trigger I/O plugging in all cases where there is no active group, and all bfq_queues have the same weight. So, in these cases some unfairness may occur if there are asymmetries in I/O-request sizes. We made this choice because I/O plugging may lower throughput, and probably a user that has not created any group cares more about throughput than about perfect fairness. At any rate, as for possible applications that may care about service guarantees, bfq already guarantees a high responsiveness and a low latency to soft real-time applications automatically. Signed-off-by: Federico Motta <federico@willer.it> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Yu Kuai <yukuai3@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* block: fix ioprio_get(IOPRIO_WHO_PGRP) vs setuid(2)Davidlohr Bueso2021-12-141-0/+3
| | | | | | | | | | | | | | | | commit e6a59aac8a8713f335a37d762db0dbe80e7f6d38 upstream. do_each_pid_thread(PIDTYPE_PGID) can race with a concurrent change_pid(PIDTYPE_PGID) that can move the task from one hlist to another while iterating. Serialize ioprio_get to take the tasklist_lock in this case, just like it's set counterpart. Fixes: d69b78ba1de (ioprio: grab rcu_read_lock in sys_ioprio_{set,get}()) Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Link: https://lore.kernel.org/r/20211210182058.43417-1-dave@stgolabs.net Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "block, bfq: honor already-setup queue merges"Jens Axboe2021-10-061-13/+3
| | | | | | | | | | | | | | | | [ Upstream commit ebc69e897e17373fbe1daaff1debaa77583a5284 ] This reverts commit 2d52c58b9c9bdae0ca3df6a1eab5745ab3f7d80b. We have had several folks complain that this causes hangs for them, which is especially problematic as the commit has also hit stable already. As no resolution seems to be forthcoming right now, revert the patch. Link: https://bugzilla.kernel.org/show_bug.cgi?id=214503 Fixes: 2d52c58b9c9b ("block, bfq: honor already-setup queue merges") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* blk-throttle: fix UAF by deleteing timer in blk_throtl_exit()Li Jinlin2021-09-261-0/+1
| | | | | | | | | | | | | | | | [ Upstream commit 884f0e84f1e3195b801319c8ec3d5774e9bf2710 ] The pending timer has been set up in blk_throtl_init(). However, the timer is not deleted in blk_throtl_exit(). This means that the timer handler may still be running after freeing the timer, which would result in a use-after-free. Fix by calling del_timer_sync() to delete the timer in blk_throtl_exit(). Signed-off-by: Li Jinlin <lijinlin3@huawei.com> Link: https://lore.kernel.org/r/20210907121242.2885564-1-lijinlin3@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* block, bfq: honor already-setup queue mergesPaolo Valente2021-09-221-3/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 2d52c58b9c9bdae0ca3df6a1eab5745ab3f7d80b ] The function bfq_setup_merge prepares the merging between two bfq_queues, say bfqq and new_bfqq. To this goal, it assigns bfqq->new_bfqq = new_bfqq. Then, each time some I/O for bfqq arrives, the process that generated that I/O is disassociated from bfqq and associated with new_bfqq (merging is actually a redirection). In this respect, bfq_setup_merge increases new_bfqq->ref in advance, adding the number of processes that are expected to be associated with new_bfqq. Unfortunately, the stable-merging mechanism interferes with this setup. After bfqq->new_bfqq has been set by bfq_setup_merge, and before all the expected processes have been associated with bfqq->new_bfqq, bfqq may happen to be stably merged with a different queue than the current bfqq->new_bfqq. In this case, bfqq->new_bfqq gets changed. So, some of the processes that have been already accounted for in the ref counter of the previous new_bfqq will not be associated with that queue. This creates an unbalance, because those references will never be decremented. This commit fixes this issue by reestablishing the previous, natural behaviour: once bfqq->new_bfqq has been set, it will not be changed until all expected redirections have occurred. Signed-off-by: Davide Zini <davidezini2@gmail.com> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Link: https://lore.kernel.org/r/20210802141352.74353-2-paolo.valente@linaro.org Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* block: bfq: fix bfq_set_next_ioprio_data()Damien Le Moal2021-09-221-1/+1
| | | | | | | | | | | | | | | | | | | commit a680dd72ec336b81511e3bff48efac6dbfa563e7 upstream. For a request that has a priority level equal to or larger than IOPRIO_BE_NR, bfq_set_next_ioprio_data() prints a critical warning but defaults to setting the request new_ioprio field to IOPRIO_BE_NR. This is not consistent with the warning and the allowed values for priority levels. Fix this by setting the request new_ioprio field to IOPRIO_BE_NR - 1, the lowest priority level allowed. Cc: <stable@vger.kernel.org> Fixes: aee69d78dec0 ("block, bfq: introduce the BFQ-v0 I/O scheduler as an extra scheduler") Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Link: https://lore.kernel.org/r/20210811033702.368488-2-damien.lemoal@wdc.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* blk-zoned: allow BLKREPORTZONE without CAP_SYS_ADMINNiklas Cassel2021-09-221-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | commit 4d643b66089591b4769bcdb6fd1bfeff2fe301b8 upstream. A user space process should not need the CAP_SYS_ADMIN capability set in order to perform a BLKREPORTZONE ioctl. Getting the zone report is required in order to get the write pointer. Neither read() nor write() requires CAP_SYS_ADMIN, so it is reasonable that a user space process that can read/write from/to the device, also can get the write pointer. (Since e.g. writes have to be at the write pointer.) Fixes: 3ed05a987e0f ("blk-zoned: implement ioctls") Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Aravind Ramesh <aravind.ramesh@wdc.com> Reviewed-by: Adam Manzanares <a.manzanares@samsung.com> Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Cc: stable@vger.kernel.org # v4.10+ Link: https://lore.kernel.org/r/20210811110505.29649-3-Niklas.Cassel@wdc.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* blk-zoned: allow zone management send operations without CAP_SYS_ADMINNiklas Cassel2021-09-221-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit ead3b768bb51259e3a5f2287ff5fc9041eb6f450 upstream. Zone management send operations (BLKRESETZONE, BLKOPENZONE, BLKCLOSEZONE and BLKFINISHZONE) should be allowed under the same permissions as write(). (write() does not require CAP_SYS_ADMIN). Additionally, other ioctls like BLKSECDISCARD and BLKZEROOUT only check if the fd was successfully opened with FMODE_WRITE. (They do not require CAP_SYS_ADMIN). Currently, zone management send operations require both CAP_SYS_ADMIN and that the fd was successfully opened with FMODE_WRITE. Remove the CAP_SYS_ADMIN requirement, so that zone management send operations match the access control requirement of write(), BLKSECDISCARD and BLKZEROOUT. Fixes: 3ed05a987e0f ("blk-zoned: implement ioctls") Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Aravind Ramesh <aravind.ramesh@wdc.com> Reviewed-by: Adam Manzanares <a.manzanares@samsung.com> Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Cc: stable@vger.kernel.org # v4.10+ Link: https://lore.kernel.org/r/20210811110505.29649-2-Niklas.Cassel@wdc.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit()Yu Kuai2021-08-121-1/+5
| | | | | | | | | | | | | | | | | | [ Upstream commit 8d75d0eff6887bcac7225e12b9c75595e523d92d ] If queue is dying while iolatency_set_limit() is in progress, blk_get_queue() won't increment the refcount of the queue. However, blk_put_queue() will still decrement the refcount later, which will cause the refcout to be unbalanced. Thus error out in such case to fix the problem. Fixes: 8c772a9bfc7c ("blk-iolatency: fix IO hang due to negative inflight counter") Signed-off-by: Yu Kuai <yukuai3@huawei.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20210805124645.543797-1-yukuai3@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* bdi: use bdi_dev_name() to get device nameYufen Yu2021-08-082-3/+5
| | | | | | | | | | | | | | | | | [ Upstream commit d51cfc53ade3189455a1b88ec7a2ff0c24597cf8 ] Use the common interface bdi_dev_name() to get device name. Signed-off-by: Yufen Yu <yuyufen@huawei.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Add missing <linux/backing-dev.h> include BFQ Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* blk-wbt: make sure throttle is enabled properlyZhang Yi2021-07-201-1/+5
| | | | | | | | | | | | | | | [ Upstream commit 76a8040817b4b9c69b53f9b326987fa891b4082a ] After commit a79050434b45 ("blk-rq-qos: refactor out common elements of blk-wbt"), if throttle was disabled by wbt_disable_default(), we could not enable again, fix this by set enable_state back to WBT_STATE_ON_DEFAULT. Fixes: a79050434b45 ("blk-rq-qos: refactor out common elements of blk-wbt") Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Link: https://lore.kernel.org/r/20210619093700.920393-3-yi.zhang@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* blk-wbt: introduce a new disable state to prevent false positive by ↵Zhang Yi2021-07-202-2/+4
| | | | | | | | | | | | | | | | | | | | rwb_enabled() [ Upstream commit 1d0903d61e9645c6330b94247b96dd873dfc11c8 ] Now that we disable wbt by simply zero out rwb->wb_normal in wbt_disable_default() when switch elevator to bfq, but it's not safe because it will become false positive if we change queue depth. If it become false positive between wbt_wait() and wbt_track() when submit write request, it will lead to drop rqw->inflight to -1 in wbt_done(), which will end up trigger IO hung. Fix this issue by introduce a new state which mean the wbt was disabled. Fixes: a79050434b45 ("blk-rq-qos: refactor out common elements of blk-wbt") Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Link: https://lore.kernel.org/r/20210619093700.920393-2-yi.zhang@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* blk-mq: Swap two calls in blk_mq_exit_queue()Bart Van Assche2021-05-221-2/+4
| | | | | | | | | | | | | | | | | | | | | [ Upstream commit 630ef623ed26c18a457cdc070cf24014e50129c2 ] If a tag set is shared across request queues (e.g. SCSI LUNs) then the block layer core keeps track of the number of active request queues in tags->active_queues. blk_mq_tag_busy() and blk_mq_tag_idle() update that atomic counter if the hctx flag BLK_MQ_F_TAG_QUEUE_SHARED is set. Make sure that blk_mq_exit_queue() calls blk_mq_tag_idle() before that flag is cleared by blk_mq_del_queue_tag_set(). Cc: Christoph Hellwig <hch@infradead.org> Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.com> Fixes: 0d2602ca30e4 ("blk-mq: improve support for shared tags maps") Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20210513171529.7977-1-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* block: only update parent bi_status when bio failYufen Yu2021-04-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 3edf5346e4f2ce2fa0c94651a90a8dda169565ee ] For multiple split bios, if one of the bio is fail, the whole should return error to application. But we found there is a race between bio_integrity_verify_fn and bio complete, which return io success to application after one of the bio fail. The race as following: split bio(READ) kworker nvme_complete_rq blk_update_request //split error=0 bio_endio bio_integrity_endio queue_work(kintegrityd_wq, &bip->bip_work); bio_integrity_verify_fn bio_endio //split bio __bio_chain_endio if (!parent->bi_status) <interrupt entry> nvme_irq blk_update_request //parent error=7 req_bio_endio bio->bi_status = 7 //parent bio <interrupt exit> parent->bi_status = 0 parent->bi_end_io() // return bi_status=0 The bio has been split as two: split and parent. When split bio completed, it depends on kworker to do endio, while bio_integrity_verify_fn have been interrupted by parent bio complete irq handler. Then, parent bio->bi_status which have been set in irq handler will overwrite by kworker. In fact, even without the above race, we also need to conside the concurrency beteen mulitple split bio complete and update the same parent bi_status. Normally, multiple split bios will be issued to the same hctx and complete from the same irq vector. But if we have updated queue map between multiple split bios, these bios may complete on different hw queue and different irq vector. Then the concurrency update parent bi_status may cause the final status error. Suggested-by: Keith Busch <kbusch@kernel.org> Signed-off-by: Yufen Yu <yuyufen@huawei.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20210331115359.1125679-1-yuyufen@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* block: Suppress uevent for hidden device when removedDaniel Wagner2021-03-301-3/+1
| | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 9ec491447b90ad6a4056a9656b13f0b3a1e83043 ] register_disk() suppress uevents for devices with the GENHD_FL_HIDDEN but enables uevents at the end again in order to announce disk after possible partitions are created. When the device is removed the uevents are still on and user land sees 'remove' messages for devices which were never 'add'ed to the system. KERNEL[95481.571887] remove /devices/virtual/nvme-fabrics/ctl/nvme5/nvme0c5n1 (block) Let's suppress the uevents for GENHD_FL_HIDDEN by not enabling the uevents at all. Signed-off-by: Daniel Wagner <dwagner@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin Wilck <mwilck@suse.com> Link: https://lore.kernel.org/r/20210311151917.136091-1-dwagner@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* block: genhd: add 'groups' argument to device_add_diskHannes Reinecke2021-03-111-5/+14
| | | | | | | | | | | | | | | | | | commit fef912bf860e8e7e48a2bfb978a356bba743a8b7 upstream. Update device_add_disk() to take an 'groups' argument so that individual drivers can register a device with additional sysfs attributes. This avoids race condition the driver would otherwise have if these groups were to be created with sysfs_add_groups(). Signed-off-by: Martin Wilck <martin.wilck@suse.com> Signed-off-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* blk-settings: align max_sectors on "logical_block_size" boundaryMikulas Patocka2021-03-041-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 97f433c3601a24d3513d06f575a389a2ca4e11e4 upstream. We get I/O errors when we run md-raid1 on the top of dm-integrity on the top of ramdisk. device-mapper: integrity: Bio not aligned on 8 sectors: 0xff00, 0xff device-mapper: integrity: Bio not aligned on 8 sectors: 0xff00, 0xff device-mapper: integrity: Bio not aligned on 8 sectors: 0xffff, 0x1 device-mapper: integrity: Bio not aligned on 8 sectors: 0xffff, 0x1 device-mapper: integrity: Bio not aligned on 8 sectors: 0x8048, 0xff device-mapper: integrity: Bio not aligned on 8 sectors: 0x8147, 0xff device-mapper: integrity: Bio not aligned on 8 sectors: 0x8246, 0xff device-mapper: integrity: Bio not aligned on 8 sectors: 0x8345, 0xbb The ramdisk device has logical_block_size 512 and max_sectors 255. The dm-integrity device uses logical_block_size 4096 and it doesn't affect the "max_sectors" value - thus, it inherits 255 from the ramdisk. So, we have a device with max_sectors not aligned on logical_block_size. The md-raid device sees that the underlying leg has max_sectors 255 and it will split the bios on 255-sector boundary, making the bios unaligned on logical_block_size. In order to fix the bug, we round down max_sectors to logical_block_size. Cc: stable@vger.kernel.org Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* bfq: Avoid false bfq queue mergingJan Kara2021-03-041-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 41e76c85660c022c6bf5713bfb6c21e64a487cec upstream. bfq_setup_cooperator() uses bfqd->in_serv_last_pos so detect whether it makes sense to merge current bfq queue with the in-service queue. However if the in-service queue is freshly scheduled and didn't dispatch any requests yet, bfqd->in_serv_last_pos is stale and contains value from the previously scheduled bfq queue which can thus result in a bogus decision that the two queues should be merged. This bug can be observed for example with the following fio jobfile: [global] direct=0 ioengine=sync invalidate=1 size=1g rw=read [reader] numjobs=4 directory=/mnt where the 4 processes will end up in the one shared bfq queue although they do IO to physically very distant files (for some reason I was able to observe this only with slice_idle=1ms setting). Fix the problem by invalidating bfqd->in_serv_last_pos when switching in-service queue. Fixes: 058fdecc6de7 ("block, bfq: fix in-service-queue check for queue merging") CC: stable@vger.kernel.org Signed-off-by: Jan Kara <jack@suse.cz> Acked-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* block: don't release queue's sysfs lock during switching elevatorMing Lei2021-03-042-31/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit b89f625e28d44552083f43752f62d8621ded0a04 upstream. cecf5d87ff20 ("block: split .sysfs_lock into two locks") starts to release & acquire sysfs_lock before registering/un-registering elevator queue during switching elevator for avoiding potential deadlock from showing & storing 'queue/iosched' attributes and removing elevator's kobject. Turns out there isn't such deadlock because 'q->sysfs_lock' isn't required in .show & .store of queue/iosched's attributes, and just elevator's sysfs lock is acquired in elv_iosched_store() and elv_iosched_show(). So it is safe to hold queue's sysfs lock when registering/un-registering elevator queue. The biggest issue is that commit cecf5d87ff20 assumes that concurrent write on 'queue/scheduler' can't happen. However, this assumption isn't true, because kernfs_fop_write() only guarantees that concurrent write aren't called on the same open file, but the write could be from different open on the file. So we can't release & re-acquire queue's sysfs lock during switching elevator, otherwise use-after-free on elevator could be triggered. Fixes the issue by not releasing queue's sysfs lock during switching elevator. Fixes: cecf5d87ff20 ("block: split .sysfs_lock into two locks") Cc: Christoph Hellwig <hch@infradead.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> (jwang: adjust ctx for 4.19) Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* block: fix race between switching elevator and removing queuesMing Lei2021-03-041-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | commit 0a67b5a926e63ff5492c3c675eab5900580d056d upstream. cecf5d87ff20 ("block: split .sysfs_lock into two locks") starts to release & actuire sysfs_lock again during switching elevator. So it isn't enough to prevent switching elevator from happening by simply clearing QUEUE_FLAG_REGISTERED with holding sysfs_lock, because in-progress switch still can move on after re-acquiring the lock, meantime the flag of QUEUE_FLAG_REGISTERED won't get checked. Fixes this issue by checking 'q->elevator' directly & locklessly after q->kobj is removed in blk_unregister_queue(), this way is safe because q->elevator can't be changed at that time. Fixes: cecf5d87ff20 ("block: split .sysfs_lock into two locks") Cc: Christoph Hellwig <hch@infradead.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* block: split .sysfs_lock into two locksMing Lei2021-03-045-33/+85
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit cecf5d87ff2035127bb5a9ee054d0023a4a7cad3 upstream. The kernfs built-in lock of 'kn->count' is held in sysfs .show/.store path. Meantime, inside block's .show/.store callback, q->sysfs_lock is required. However, when mq & iosched kobjects are removed via blk_mq_unregister_dev() & elv_unregister_queue(), q->sysfs_lock is held too. This way causes AB-BA lock because the kernfs built-in lock of 'kn-count' is required inside kobject_del() too, see the lockdep warning[1]. On the other hand, it isn't necessary to acquire q->sysfs_lock for both blk_mq_unregister_dev() & elv_unregister_queue() because clearing REGISTERED flag prevents storing to 'queue/scheduler' from being happened. Also sysfs write(store) is exclusive, so no necessary to hold the lock for elv_unregister_queue() when it is called in switching elevator path. So split .sysfs_lock into two: one is still named as .sysfs_lock for covering sync .store, the other one is named as .sysfs_dir_lock for covering kobjects and related status change. sysfs itself can handle the race between add/remove kobjects and showing/storing attributes under kobjects. For switching scheduler via storing to 'queue/scheduler', we use the queue flag of QUEUE_FLAG_REGISTERED with .sysfs_lock for avoiding the race, then we can avoid to hold .sysfs_lock during removing/adding kobjects. [1] lockdep warning ====================================================== WARNING: possible circular locking dependency detected 5.3.0-rc3-00044-g73277fc75ea0 #1380 Not tainted ------------------------------------------------------ rmmod/777 is trying to acquire lock: 00000000ac50e981 (kn->count#202){++++}, at: kernfs_remove_by_name_ns+0x59/0x72 but task is already holding lock: 00000000fb16ae21 (&q->sysfs_lock){+.+.}, at: blk_unregister_queue+0x78/0x10b which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&q->sysfs_lock){+.+.}: __lock_acquire+0x95f/0xa2f lock_acquire+0x1b4/0x1e8 __mutex_lock+0x14a/0xa9b blk_mq_hw_sysfs_show+0x63/0xb6 sysfs_kf_seq_show+0x11f/0x196 seq_read+0x2cd/0x5f2 vfs_read+0xc7/0x18c ksys_read+0xc4/0x13e do_syscall_64+0xa7/0x295 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (kn->count#202){++++}: check_prev_add+0x5d2/0xc45 validate_chain+0xed3/0xf94 __lock_acquire+0x95f/0xa2f lock_acquire+0x1b4/0x1e8 __kernfs_remove+0x237/0x40b kernfs_remove_by_name_ns+0x59/0x72 remove_files+0x61/0x96 sysfs_remove_group+0x81/0xa4 sysfs_remove_groups+0x3b/0x44 kobject_del+0x44/0x94 blk_mq_unregister_dev+0x83/0xdd blk_unregister_queue+0xa0/0x10b del_gendisk+0x259/0x3fa null_del_dev+0x8b/0x1c3 [null_blk] null_exit+0x5c/0x95 [null_blk] __se_sys_delete_module+0x204/0x337 do_syscall_64+0xa7/0x295 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&q->sysfs_lock); lock(kn->count#202); lock(&q->sysfs_lock); lock(kn->count#202); *** DEADLOCK *** 2 locks held by rmmod/777: #0: 00000000e69bd9de (&lock){+.+.}, at: null_exit+0x2e/0x95 [null_blk] #1: 00000000fb16ae21 (&q->sysfs_lock){+.+.}, at: blk_unregister_queue+0x78/0x10b stack backtrace: CPU: 0 PID: 777 Comm: rmmod Not tainted 5.3.0-rc3-00044-g73277fc75ea0 #1380 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS ?-20180724_192412-buildhw-07.phx4 Call Trace: dump_stack+0x9a/0xe6 check_noncircular+0x207/0x251 ? print_circular_bug+0x32a/0x32a ? find_usage_backwards+0x84/0xb0 check_prev_add+0x5d2/0xc45 validate_chain+0xed3/0xf94 ? check_prev_add+0xc45/0xc45 ? mark_lock+0x11b/0x804 ? check_usage_forwards+0x1ca/0x1ca __lock_acquire+0x95f/0xa2f lock_acquire+0x1b4/0x1e8 ? kernfs_remove_by_name_ns+0x59/0x72 __kernfs_remove+0x237/0x40b ? kernfs_remove_by_name_ns+0x59/0x72 ? kernfs_next_descendant_post+0x7d/0x7d ? strlen+0x10/0x23 ? strcmp+0x22/0x44 kernfs_remove_by_name_ns+0x59/0x72 remove_files+0x61/0x96 sysfs_remove_group+0x81/0xa4 sysfs_remove_groups+0x3b/0x44 kobject_del+0x44/0x94 blk_mq_unregister_dev+0x83/0xdd blk_unregister_queue+0xa0/0x10b del_gendisk+0x259/0x3fa ? disk_events_poll_msecs_store+0x12b/0x12b ? check_flags+0x1ea/0x204 ? mark_held_locks+0x1f/0x7a null_del_dev+0x8b/0x1c3 [null_blk] null_exit+0x5c/0x95 [null_blk] __se_sys_delete_module+0x204/0x337 ? free_module+0x39f/0x39f ? blkcg_maybe_throttle_current+0x8a/0x718 ? rwlock_bug+0x62/0x62 ? __blkcg_punt_bio_submit+0xd0/0xd0 ? trace_hardirqs_on_thunk+0x1a/0x20 ? mark_held_locks+0x1f/0x7a ? do_syscall_64+0x4c/0x295 do_syscall_64+0xa7/0x295 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7fb696cdbe6b Code: 73 01 c3 48 8b 0d 1d 20 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 008 RSP: 002b:00007ffec9588788 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0 RAX: ffffffffffffffda RBX: 0000559e589137c0 RCX: 00007fb696cdbe6b RDX: 000000000000000a RSI: 0000000000000800 RDI: 0000559e58913828 RBP: 0000000000000000 R08: 00007ffec9587701 R09: 0000000000000000 R10: 00007fb696d4eae0 R11: 0000000000000206 R12: 00007ffec95889b0 R13: 00007ffec95896b3 R14: 0000559e58913260 R15: 0000559e589137c0 Cc: Christoph Hellwig <hch@infradead.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> (jwang:cherry picked from commit cecf5d87ff2035127bb5a9ee054d0023a4a7cad3, adjust ctx for 4,19) Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* block: add helper for checking if queue is registeredMing Lei2021-03-043-4/+4
| | | | | | | | | | | | | | | | | | commit 58c898ba370e68d39470cd0d932b524682c1f9be upstream. There are 4 users which check if queue is registered, so add one helper to check it. Cc: Christoph Hellwig <hch@infradead.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-08 01:14:20 +0000