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* io-wq: fully initialize wqe before calling cpuhp_state_add_instance_nocalls()Jeff Moyer2023-10-051-6/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I received a bug report with the following signature: [ 1759.937637] BUG: unable to handle page fault for address: ffffffffffffffe8 [ 1759.944564] #PF: supervisor read access in kernel mode [ 1759.949732] #PF: error_code(0x0000) - not-present page [ 1759.954901] PGD 7ab615067 P4D 7ab615067 PUD 7ab617067 PMD 0 [ 1759.960596] Oops: 0000 1 PREEMPT SMP PTI [ 1759.964804] CPU: 15 PID: 109 Comm: cpuhp/15 Kdump: loaded Tainted: G X ------- — 5.14.0-362.3.1.el9_3.x86_64 #1 [ 1759.976609] Hardware name: HPE ProLiant DL380 Gen10/ProLiant DL380 Gen10, BIOS U30 06/20/2018 [ 1759.985181] RIP: 0010:io_wq_for_each_worker.isra.0+0x24/0xa0 [ 1759.990877] Code: 90 90 90 90 90 90 0f 1f 44 00 00 41 56 41 55 41 54 55 48 8d 6f 78 53 48 8b 47 78 48 39 c5 74 4f 49 89 f5 49 89 d4 48 8d 58 e8 <8b> 13 85 d2 74 32 8d 4a 01 89 d0 f0 0f b1 0b 75 5c 09 ca 78 3d 48 [ 1760.009758] RSP: 0000:ffffb6f403603e20 EFLAGS: 00010286 [ 1760.015013] RAX: 0000000000000000 RBX: ffffffffffffffe8 RCX: 0000000000000000 [ 1760.022188] RDX: ffffb6f403603e50 RSI: ffffffffb11e95b0 RDI: ffff9f73b09e9400 [ 1760.029362] RBP: ffff9f73b09e9478 R08: 000000000000000f R09: 0000000000000000 [ 1760.036536] R10: ffffffffffffff00 R11: ffffb6f403603d80 R12: ffffb6f403603e50 [ 1760.043712] R13: ffffffffb11e95b0 R14: ffffffffb28531e8 R15: ffff9f7a6fbdf548 [ 1760.050887] FS: 0000000000000000(0000) GS:ffff9f7a6fbc0000(0000) knlGS:0000000000000000 [ 1760.059025] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1760.064801] CR2: ffffffffffffffe8 CR3: 00000007ab610002 CR4: 00000000007706e0 [ 1760.071976] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1760.079150] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1760.086325] PKRU: 55555554 [ 1760.089044] Call Trace: [ 1760.091501] <TASK> [ 1760.093612] ? show_trace_log_lvl+0x1c4/0x2df [ 1760.097995] ? show_trace_log_lvl+0x1c4/0x2df [ 1760.102377] ? __io_wq_cpu_online+0x54/0xb0 [ 1760.106584] ? __die_body.cold+0x8/0xd [ 1760.110356] ? page_fault_oops+0x134/0x170 [ 1760.114479] ? kernelmode_fixup_or_oops+0x84/0x110 [ 1760.119298] ? exc_page_fault+0xa8/0x150 [ 1760.123247] ? asm_exc_page_fault+0x22/0x30 [ 1760.127458] ? __pfx_io_wq_worker_affinity+0x10/0x10 [ 1760.132453] ? __pfx_io_wq_worker_affinity+0x10/0x10 [ 1760.137446] ? io_wq_for_each_worker.isra.0+0x24/0xa0 [ 1760.142527] __io_wq_cpu_online+0x54/0xb0 [ 1760.146558] cpuhp_invoke_callback+0x109/0x460 [ 1760.151029] ? __pfx_io_wq_cpu_offline+0x10/0x10 [ 1760.155673] ? __pfx_smpboot_thread_fn+0x10/0x10 [ 1760.160320] cpuhp_thread_fun+0x8d/0x140 [ 1760.164266] smpboot_thread_fn+0xd3/0x1a0 [ 1760.168297] kthread+0xdd/0x100 [ 1760.171457] ? __pfx_kthread+0x10/0x10 [ 1760.175225] ret_from_fork+0x29/0x50 [ 1760.178826] </TASK> [ 1760.181022] Modules linked in: rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache netfs rfkill sunrpc vfat fat dm_multipath intel_rapl_msr intel_rapl_common isst_if_common ipmi_ssif nfit libnvdimm mgag200 i2c_algo_bit ioatdma drm_shmem_helper drm_kms_helper acpi_ipmi syscopyarea x86_pkg_temp_thermal sysfillrect ipmi_si intel_powerclamp sysimgblt ipmi_devintf coretemp acpi_power_meter ipmi_msghandler rapl pcspkr dca intel_pch_thermal intel_cstate ses lpc_ich intel_uncore enclosure hpilo mei_me mei acpi_tad fuse drm xfs sd_mod sg bnx2x nvme nvme_core crct10dif_pclmul crc32_pclmul nvme_common ghash_clmulni_intel smartpqi tg3 t10_pi mdio uas libcrc32c crc32c_intel scsi_transport_sas usb_storage hpwdt wmi dm_mirror dm_region_hash dm_log dm_mod [ 1760.248623] CR2: ffffffffffffffe8 A cpu hotplug callback was issued before wq->all_list was initialized. This results in a null pointer dereference. The fix is to fully setup the io_wq before calling cpuhp_state_add_instance_nocalls(). Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Link: https://lore.kernel.org/r/x49y1ghnecs.fsf@segfault.boston.devel.redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: break out of iowq iopoll on teardownPavel Begunkov2023-09-071-0/+10
| | | | | | | | | | | | | io-wq will retry iopoll even when it failed with -EAGAIN. If that races with task exit, which sets TIF_NOTIFY_SIGNAL for all its workers, such workers might potentially infinitely spin retrying iopoll again and again and each time failing on some allocation / waiting / etc. Don't keep spinning if io-wq is dying. Fixes: 561fb04a6a225 ("io_uring: replace workqueue usage with io-wq") Cc: stable@vger.kernel.org Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/sqpoll: fix io-wq affinity when IORING_SETUP_SQPOLL is usedJens Axboe2023-08-161-3/+6
| | | | | | | | | | | | | | | If we setup the ring with SQPOLL, then that polling thread has its own io-wq setup. This means that if the application uses IORING_REGISTER_IOWQ_AFF to set the io-wq affinity, we should not be setting it for the invoking task, but rather the sqpoll task. Add an sqpoll helper that parks the thread and updates the affinity, and use that one if we're using SQPOLL. Fixes: fe76421d1da1 ("io_uring: allow user configurable IO thread CPU affinity") Cc: stable@vger.kernel.org # 5.10+ Link: https://github.com/axboe/liburing/discussions/884 Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/io-wq: don't gate worker wake up success on wake_up_process()Jens Axboe2023-08-111-4/+7
| | | | | | | | | | | | | | | All we really care about is finding a free worker. If said worker is already running, it's either starting new work already or it's just finishing up existing work. For the latter, we'll be finding this work item next anyway, and for the former, if the worker does go to sleep, it'll create a new worker anyway as we have pending items. This reduces try_to_wake_up() overhead considerably: 23.16% -10.46% [kernel.kallsyms] [k] try_to_wake_up Reviewed-by: Hao Xu <howeyxu@tencent.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/io-wq: reduce frequency of acct->lock acquisitionsJens Axboe2023-08-111-13/+34
| | | | | | | | | | | | | | | | | | | | When we check if we have work to run, we grab the acct lock, check, drop it, and then return the result. If we do have work to run, then running the work will again grab acct->lock and get the work item. This causes us to grab acct->lock more frequently than we need to. If we have work to do, have io_acct_run_queue() return with the acct lock still acquired. io_worker_handle_work() is then always invoked with the acct lock already held. In a simple test cases that stats files (IORING_OP_STATX always hits io-wq), we see a nice reduction in locking overhead with this change: 19.32% -12.55% [kernel.kallsyms] [k] __cmpwait_case_32 20.90% -12.07% [kernel.kallsyms] [k] queued_spin_lock_slowpath Reviewed-by: Hao Xu <howeyxu@tencent.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/io-wq: don't grab wq->lock for worker activationJens Axboe2023-08-111-3/+0
| | | | | | | | | The worker free list is RCU protected, and checks for workers going away when iterating it. There's no need to hold the wq->lock around the lookup. Reviewed-by: Hao Xu <howeyxu@tencent.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/io-wq: clear current->worker_private on exitJens Axboe2023-06-141-1/+6
| | | | | | | | | | | | | | | | | | | A recent fix stopped clearing PF_IO_WORKER from current->flags on exit, which meant that we can now call inc/dec running on the worker after it has been removed if it ends up scheduling in/out as part of exit. If this happens after an RCU grace period has passed, then the struct pointed to by current->worker_private may have been freed, and we can now be accessing memory that is freed. Ensure this doesn't happen by clearing the task worker_private field. Both io_wq_worker_running() and io_wq_worker_sleeping() check this field before going any further, and we don't need any accounting etc done after this worker has exited. Fixes: fd37b884003c ("io_uring/io-wq: don't clear PF_IO_WORKER on exit") Reported-by: Zorro Lang <zlang@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/io-wq: don't clear PF_IO_WORKER on exitJens Axboe2023-06-121-3/+0
| | | | | | | | | | | | | | | | | | | | A recent commit gated the core dumping task exit logic on current->flags remaining consistent in terms of PF_{IO,USER}_WORKER at task exit time. This exposed a problem with the io-wq handling of that, which explicitly clears PF_IO_WORKER before calling do_exit(). The reasons for this manual clear of PF_IO_WORKER is historical, where io-wq used to potentially trigger a sleep on exit. As the io-wq thread is exiting, it should not participate any further accounting. But these days we don't need to rely on current->flags anymore, so we can safely remove the PF_IO_WORKER clearing. Reported-by: Zorro Lang <zlang@redhat.com> Reported-by: Dave Chinner <david@fromorbit.com> Link: https://lore.kernel.org/all/ZIZSPyzReZkGBEFy@dread.disaster.area/ Fixes: f9010dbdce91 ("fork, vhost: Use CLONE_THREAD to fix freezer/ps regression") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* io_uring/io-wq: drop outdated commentJens Axboe2023-04-031-5/+1
| | | | | | | Since the move to PF_IO_WORKER, we don't juggle memory context manually anymore. Remove that outdated part of the comment for __io_worker_idle(). Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: Drop struct io_wqeGabriel Krisman Bertazi2023-04-031-188/+156
| | | | | | | | | | | | | | | Since commit 0654b05e7e65 ("io_uring: One wqe per wq"), we have just a single io_wqe instance embedded per io_wq. Drop the extra structure in favor of accessing struct io_wq directly, cleaning up quite a bit of dereferences and backpointers. No functional changes intended. Tested with liburing's testsuite and mmtests performance microbenchmarks. I didn't observe any performance regressions. Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de> Link: https://lore.kernel.org/r/20230322011628.23359-2-krisman@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: Move wq accounting to io_wqGabriel Krisman Bertazi2023-04-031-38/+40
| | | | | | | | | | Since we now have a single io_wqe per io_wq instead of per-node, and in preparation to its removal, move the accounting into the parent structure. Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de> Link: https://lore.kernel.org/r/20230322011628.23359-2-krisman@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: One wqe per wqBreno Leitao2023-04-031-110/+70
| | | | | | | | | | | | | | Right now io_wq allocates one io_wqe per NUMA node. As io_wq is now bound to a task, the task basically uses only the NUMA local io_wqe, and almost never changes NUMA nodes, thus, the other wqes are mostly unused. Allocate just one io_wqe embedded into io_wq, and uses all possible cpus (cpu_possible_mask) in the io_wqe->cpumask. Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://lore.kernel.org/r/20230310201107.4020580-1-leitao@debian.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/io-wq: stop setting PF_NO_SETAFFINITY on io-wq workersJens Axboe2023-03-081-5/+11
| | | | | | | | | | | | | | | | | | | Every now and then reports come in that are puzzled on why changing affinity on the io-wq workers fails with EINVAL. This happens because they set PF_NO_SETAFFINITY as part of their creation, as io-wq organizes workers into groups based on what CPU they are running on. However, this is purely an optimization and not a functional requirement. We can allow setting affinity, and just lazily update our worker to wqe mappings. If a given io-wq thread times out, it normally exits if there's no more work to do. The exception is if it's the last worker available. For the timeout case, check the affinity of the worker against group mask and exit even if it's the last worker. New workers should be created with the right mask and in the right location. Reported-by:Daniel Dao <dqminh@cloudflare.com> Link: https://lore.kernel.org/io-uring/CA+wXwBQwgxB3_UphSny-yAP5b26meeOu1W4TwYVcD_+5gOhvPw@mail.gmail.com/ Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/io-wq: only free worker if it was allocated for creationJens Axboe2023-01-081-1/+6
| | | | | | | | | | | We have two types of task_work based creation, one is using an existing worker to setup a new one (eg when going to sleep and we have no free workers), and the other is allocating a new worker. Only the latter should be freed when we cancel task_work creation for a new worker. Fixes: af82425c6a2d ("io_uring/io-wq: free worker if task_work creation is canceled") Reported-by: syzbot+d56ec896af3637bdb7e4@syzkaller.appspotmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/io-wq: free worker if task_work creation is canceledJens Axboe2023-01-021-0/+1
| | | | | | | | | | If we cancel the task_work, the worker will never come into existance. As this is the last reference to it, ensure that we get it freed appropriately. Cc: stable@vger.kernel.org Reported-by: 진호 <wnwlsgh98@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: Fix memory leak in worker creationRafael Mendonca2022-10-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the CPU mask allocation for a node fails, then the memory allocated for the 'io_wqe' struct of the current node doesn't get freed on the error handling path, since it has not yet been added to the 'wqes' array. This was spotted when fuzzing v6.1-rc1 with Syzkaller: BUG: memory leak unreferenced object 0xffff8880093d5000 (size 1024): comm "syz-executor.2", pid 7701, jiffies 4295048595 (age 13.900s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000cb463369>] __kmem_cache_alloc_node+0x18e/0x720 [<00000000147a3f9c>] kmalloc_node_trace+0x2a/0x130 [<000000004e107011>] io_wq_create+0x7b9/0xdc0 [<00000000c38b2018>] io_uring_alloc_task_context+0x31e/0x59d [<00000000867399da>] __io_uring_add_tctx_node.cold+0x19/0x1ba [<000000007e0e7a79>] io_uring_setup.cold+0x1b80/0x1dce [<00000000b545e9f6>] __x64_sys_io_uring_setup+0x5d/0x80 [<000000008a8a7508>] do_syscall_64+0x5d/0x90 [<000000004ac08bec>] entry_SYSCALL_64_after_hwframe+0x63/0xcd Fixes: 0e03496d1967 ("io-wq: use private CPU mask") Cc: stable@vger.kernel.org Signed-off-by: Rafael Mendonca <rafaelmendsr@gmail.com> Link: https://lore.kernel.org/r/20221020014710.902201-1-rafaelmendsr@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* audit, io_uring, io-wq: Fix memory leak in io_sq_thread() and io_wqe_worker()Peilin Ye2022-08-041-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently @audit_context is allocated twice for io_uring workers: 1. copy_process() calls audit_alloc(); 2. io_sq_thread() or io_wqe_worker() calls audit_alloc_kernel() (which is effectively audit_alloc()) and overwrites @audit_context, causing: BUG: memory leak unreferenced object 0xffff888144547400 (size 1024): <...> hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff8135cfc3>] audit_alloc+0x133/0x210 [<ffffffff81239e63>] copy_process+0xcd3/0x2340 [<ffffffff8123b5f3>] create_io_thread+0x63/0x90 [<ffffffff81686604>] create_io_worker+0xb4/0x230 [<ffffffff81686f68>] io_wqe_enqueue+0x248/0x3b0 [<ffffffff8167663a>] io_queue_iowq+0xba/0x200 [<ffffffff816768b3>] io_queue_async+0x113/0x180 [<ffffffff816840df>] io_req_task_submit+0x18f/0x1a0 [<ffffffff816841cd>] io_apoll_task_func+0xdd/0x120 [<ffffffff8167d49f>] tctx_task_work+0x11f/0x570 [<ffffffff81272c4e>] task_work_run+0x7e/0xc0 [<ffffffff8125a688>] get_signal+0xc18/0xf10 [<ffffffff8111645b>] arch_do_signal_or_restart+0x2b/0x730 [<ffffffff812ea44e>] exit_to_user_mode_prepare+0x5e/0x180 [<ffffffff844ae1b2>] syscall_exit_to_user_mode+0x12/0x20 [<ffffffff844a7e80>] do_syscall_64+0x40/0x80 Then, 3. io_sq_thread() or io_wqe_worker() frees @audit_context using audit_free(); 4. do_exit() eventually calls audit_free() again, which is okay because audit_free() does a NULL check. As suggested by Paul Moore, fix it by deleting audit_alloc_kernel() and redundant audit_free() calls. Fixes: 5bd2182d58e9 ("audit,io_uring,io-wq: add some basic audit support to io_uring") Suggested-by: Paul Moore <paul@paul-moore.com> Cc: stable@vger.kernel.org Signed-off-by: Peilin Ye <peilin.ye@bytedance.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20220803222343.31673-1-yepeilin.cs@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: dedup io_run_task_workPavel Begunkov2022-07-241-14/+3
| | | | | | | | | We have an identical copy of io_run_task_work() for io-wq called io_flush_signals(), deduplicate them. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/a157a4df5fa217b8bd03c73494f2fd0e24e44fbc.1655802465.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: move list helpers to a separate filePavel Begunkov2022-07-241-0/+1
| | | | | | | | | It's annoying to have io-wq.h as a dependency every time we want some of struct io_wq_work_list helpers, move them into a separate file. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/c1d891ce12b30767d1d2a3b7db2ca3abc1ecc4a2.1655802465.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: move to separate directoryJens Axboe2022-07-241-0/+1424
In preparation for splitting io_uring up a bit, move it into its own top level directory. It didn't really belong in fs/ anyway, as it's not a file system only API. This adds io_uring/ and moves the core files in there, and updates the MAINTAINERS file for the new location. Signed-off-by: Jens Axboe <axboe@kernel.dk>
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