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* proc: convert everything to "struct proc_ops"Alexey Dobriyan2020-02-041-7/+7
| | | | | | | | | | | | | | | | | | | | | | | The most notable change is DEFINE_SHOW_ATTRIBUTE macro split in seq_file.h. Conversion rule is: llseek => proc_lseek unlocked_ioctl => proc_ioctl xxx => proc_xxx delete ".owner = THIS_MODULE" line [akpm@linux-foundation.org: fix drivers/isdn/capi/kcapi_proc.c] [sfr@canb.auug.org.au: fix kernel/sched/psi.c] Link: http://lkml.kernel.org/r/20200122180545.36222f50@canb.auug.org.au Link: http://lkml.kernel.org/r/20191225172546.GB13378@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/msg.c: consolidate all xxxctl_down() functionsLu Shuaibing2020-02-041-9/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A use of uninitialized memory in msgctl_down() because msqid64 in ksys_msgctl hasn't been initialized. The local | msqid64 | is created in ksys_msgctl() and then passed into msgctl_down(). Along the way msqid64 is never initialized before msgctl_down() checks msqid64->msg_qbytes. KUMSAN(KernelUninitializedMemorySantizer, a new error detection tool) reports: ================================================================== BUG: KUMSAN: use of uninitialized memory in msgctl_down+0x94/0x300 Read of size 8 at addr ffff88806bb97eb8 by task syz-executor707/2022 CPU: 0 PID: 2022 Comm: syz-executor707 Not tainted 5.2.0-rc4+ #63 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 Call Trace: dump_stack+0x75/0xae __kumsan_report+0x17c/0x3e6 kumsan_report+0xe/0x20 msgctl_down+0x94/0x300 ksys_msgctl.constprop.14+0xef/0x260 do_syscall_64+0x7e/0x1f0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x4400e9 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffd869e0598 EFLAGS: 00000246 ORIG_RAX: 0000000000000047 RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004400e9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00000000006ca018 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 0000000000401970 R13: 0000000000401a00 R14: 0000000000000000 R15: 0000000000000000 The buggy address belongs to the page: page:ffffea0001aee5c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 flags: 0x100000000000000() raw: 0100000000000000 0000000000000000 ffffffff01ae0101 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kumsan: bad access detected ================================================================== Syzkaller reproducer: msgctl$IPC_RMID(0x0, 0x0) C reproducer: // autogenerated by syzkaller (https://github.com/google/syzkaller) int main(void) { syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0); syscall(__NR_msgctl, 0, 0, 0); return 0; } [natechancellor@gmail.com: adjust indentation in ksys_msgctl] Link: https://github.com/ClangBuiltLinux/linux/issues/829 Link: http://lkml.kernel.org/r/20191218032932.37479-1-natechancellor@gmail.com Link: http://lkml.kernel.org/r/20190613014044.24234-1-shuaibinglu@126.com Signed-off-by: Lu Shuaibing <shuaibinglu@126.com> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Arnd Bergmann <arnd@arndb.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: NeilBrown <neilb@suse.com> From: Andrew Morton <akpm@linux-foundation.org> Subject: drivers/block/null_blk_main.c: fix layout Each line here overflows 80 cols by exactly one character. Delete one tab per line to fix. Cc: Shaohua Li <shli@fb.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/sem.c: document and update memory barriersManfred Spraul2020-02-041-25/+41
| | | | | | | | | | | | | | | | | | | | | | | | | Document and update the memory barriers in ipc/sem.c: - Add smp_store_release() to wake_up_sem_queue_prepare() and document why it is needed. - Read q->status using READ_ONCE+smp_acquire__after_ctrl_dep(). as the pair for the barrier inside wake_up_sem_queue_prepare(). - Add comments to all barriers, and mention the rules in the block regarding locking. - Switch to using wake_q_add_safe(). Link: http://lkml.kernel.org/r/20191020123305.14715-6-manfred@colorfullife.com Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Waiman Long <longman@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: <1vier1@web.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/msg.c: update and document memory barriersManfred Spraul2020-02-041-7/+36
| | | | | | | | | | | | | | | | | | | | | Transfer findings from ipc/mqueue.c: - A control barrier was missing for the lockless receive case So in theory, not yet initialized data may have been copied to user space - obviously only for architectures where control barriers are not NOP. - use smp_store_release(). In theory, the refount may have been decreased to 0 already when wake_q_add() tries to get a reference. Link: http://lkml.kernel.org/r/20191020123305.14715-5-manfred@colorfullife.com Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Waiman Long <longman@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: <1vier1@web.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/mqueue.c: update/document memory barriersManfred Spraul2020-02-041-14/+78
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Update and document memory barriers for mqueue.c: - ewp->state is read without any locks, thus READ_ONCE is required. - add smp_aquire__after_ctrl_dep() after the READ_ONCE, we need acquire semantics if the value is STATE_READY. - use wake_q_add_safe() - document why __set_current_state() may be used: Reading task->state cannot happen before the wake_q_add() call, which happens while holding info->lock. Thus the spin_unlock() is the RELEASE, and the spin_lock() is the ACQUIRE. For completeness: there is also a 3 CPU scenario, if the to be woken up task is already on another wake_q. Then: - CPU1: spin_unlock() of the task that goes to sleep is the RELEASE - CPU2: the spin_lock() of the waker is the ACQUIRE - CPU2: smp_mb__before_atomic inside wake_q_add() is the RELEASE - CPU3: smp_mb__after_spinlock() inside try_to_wake_up() is the ACQUIRE Link: http://lkml.kernel.org/r/20191020123305.14715-4-manfred@colorfullife.com Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Cc: Waiman Long <longman@redhat.com> Cc: <1vier1@web.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/mqueue.c: remove duplicated codeDavidlohr Bueso2020-02-041-13/+18
| | | | | | | | | | | | | | | pipelined_send() and pipelined_receive() are identical, so merge them. [manfred@colorfullife.com: add changelog] Link: http://lkml.kernel.org/r/20191020123305.14715-3-manfred@colorfullife.com Signed-off-by: Davidlohr Bueso <dave@stgolabs.net> Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: <1vier1@web.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* treewide: Use sizeof_field() macroPankaj Bharadiya2019-12-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | Replace all the occurrences of FIELD_SIZEOF() with sizeof_field() except at places where these are defined. Later patches will remove the unused definition of FIELD_SIZEOF(). This patch is generated using following script: EXCLUDE_FILES="include/linux/stddef.h|include/linux/kernel.h" git grep -l -e "\bFIELD_SIZEOF\b" | while read file; do if [[ "$file" =~ $EXCLUDE_FILES ]]; then continue fi sed -i -e 's/\bFIELD_SIZEOF\b/sizeof_field/g' $file; done Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com> Link: https://lore.kernel.org/r/20190924105839.110713-3-pankaj.laxminarayan.bharadiya@intel.com Co-developed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: David Miller <davem@davemloft.net> # for net
* y2038: remove CONFIG_64BIT_TIMEArnd Bergmann2019-11-151-1/+1
| | | | | | | The CONFIG_64BIT_TIME option is defined on all architectures, and can be removed for simplicity now. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
* ipc/sem.c: convert to use built-in RCU list checkingJoel Fernandes (Google)2019-09-251-1/+2
| | | | | | | | | | | | | | | | | | | | CONFIG_PROVE_RCU_LIST requires list_for_each_entry_rcu() to pass a lockdep expression if using srcu or locking for protection. It can only check regular RCU protection, all other protection needs to be passed as lockdep expression. Link: http://lkml.kernel.org/r/20190830231817.76862-2-joel@joelfernandes.org Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com> Cc: Jonathan Derrick <jonathan.derrick@intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/mqueue: improve exception handling in do_mq_notify()Markus Elfring2019-09-251-12/+8
| | | | | | | | | | | | | | | | | | Null pointers were assigned to local variables in a few cases as exception handling. The jump target “out” was used where no meaningful data processing actions should eventually be performed by branches of an if statement then. Use an additional jump target for calling dev_kfree_skb() directly. Return also directly after error conditions were detected when no extra clean-up is needed by this function implementation. Link: http://lkml.kernel.org/r/592ef10e-0b69-72d0-9789-fc48f638fdfd@web.de Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/mqueue.c: delete an unnecessary check before the macro call dev_kfree_skb()Markus Elfring2019-09-251-1/+1
| | | | | | | | | | | | | | dev_kfree_skb() input parameter validation, thus the test around the call is not needed. This issue was detected by using the Coccinelle software. Link: http://lkml.kernel.org/r/07477187-63e5-cc80-34c1-32dd16b38e12@web.de Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'work.mount-base' of ↵Linus Torvalds2019-09-181-2/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs mount API infrastructure updates from Al Viro: "Infrastructure bits of mount API conversions. The rest is more of per-filesystem updates and that will happen in separate pull requests" * 'work.mount-base' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: mtd: Provide fs_context-aware mount_mtd() replacement vfs: Create fs_context-aware mount_bdev() replacement new helper: get_tree_keyed() vfs: set fs_context::user_ns for reconfigure
| * new helper: get_tree_keyed()Al Viro2019-09-051-2/+1
| | | | | | | | | | | | For vfs_get_keyed_super users. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | ipc: fix sparc64 ipc() wrapperArnd Bergmann2019-09-071-23/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | Matt bisected a sparc64 specific issue with semctl, shmctl and msgctl to a commit from my y2038 series in linux-5.1, as I missed the custom sys_ipc() wrapper that sparc64 uses in place of the generic version that I patched. The problem is that the sys_{sem,shm,msg}ctl() functions in the kernel now do not allow being called with the IPC_64 flag any more, resulting in a -EINVAL error when they don't recognize the command. Instead, the correct way to do this now is to call the internal ksys_old_{sem,shm,msg}ctl() functions to select the API version. As we generally move towards these functions anyway, change all of sparc_ipc() to consistently use those in place of the sys_*() versions, and move the required ksys_*() declarations into linux/syscalls.h The IS_ENABLED(CONFIG_SYSVIPC) check is required to avoid link errors when ipc is disabled. Reported-by: Matt Turner <mattst88@gmail.com> Fixes: 275f22148e87 ("ipc: rename old-style shmctl/semctl/msgctl syscalls") Cc: stable@vger.kernel.org Tested-by: Matt Turner <mattst88@gmail.com> Tested-by: Anatoly Pugachev <matorola@gmail.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
* Merge branch 'work.mount0' of ↵Linus Torvalds2019-07-191-4/+5
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs mount updates from Al Viro: "The first part of mount updates. Convert filesystems to use the new mount API" * 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits) mnt_init(): call shmem_init() unconditionally constify ksys_mount() string arguments don't bother with registering rootfs init_rootfs(): don't bother with init_ramfs_fs() vfs: Convert smackfs to use the new mount API vfs: Convert selinuxfs to use the new mount API vfs: Convert securityfs to use the new mount API vfs: Convert apparmorfs to use the new mount API vfs: Convert openpromfs to use the new mount API vfs: Convert xenfs to use the new mount API vfs: Convert gadgetfs to use the new mount API vfs: Convert oprofilefs to use the new mount API vfs: Convert ibmasmfs to use the new mount API vfs: Convert qib_fs/ipathfs to use the new mount API vfs: Convert efivarfs to use the new mount API vfs: Convert configfs to use the new mount API vfs: Convert binfmt_misc to use the new mount API convenience helper: get_tree_single() convenience helper get_tree_nodev() vfs: Kill sget_userns() ...
| * mqueue: set ->user_ns before ->get_tree()Al Viro2019-05-251-4/+5
| | | | | | | | | | | | | | ... so that we could lift the capability checks into ->get_tree() caller Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | proc/sysctl: add shared variables for range checkMatteo Croce2019-07-181-19/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the sysctl code the proc_dointvec_minmax() function is often used to validate the user supplied value between an allowed range. This function uses the extra1 and extra2 members from struct ctl_table as minimum and maximum allowed value. On sysctl handler declaration, in every source file there are some readonly variables containing just an integer which address is assigned to the extra1 and extra2 members, so the sysctl range is enforced. The special values 0, 1 and INT_MAX are very often used as range boundary, leading duplication of variables like zero=0, one=1, int_max=INT_MAX in different source files: $ git grep -E '\.extra[12].*&(zero|one|int_max)' |wc -l 248 Add a const int array containing the most commonly used values, some macros to refer more easily to the correct array member, and use them instead of creating a local one for every object file. This is the bloat-o-meter output comparing the old and new binary compiled with the default Fedora config: # scripts/bloat-o-meter -d vmlinux.o.old vmlinux.o add/remove: 2/2 grow/shrink: 0/2 up/down: 24/-188 (-164) Data old new delta sysctl_vals - 12 +12 __kstrtab_sysctl_vals - 12 +12 max 14 10 -4 int_max 16 - -16 one 68 - -68 zero 128 28 -100 Total: Before=20583249, After=20583085, chg -0.00% [mcroce@redhat.com: tipc: remove two unused variables] Link: http://lkml.kernel.org/r/20190530091952.4108-1-mcroce@redhat.com [akpm@linux-foundation.org: fix net/ipv6/sysctl_net_ipv6.c] [arnd@arndb.de: proc/sysctl: make firmware loader table conditional] Link: http://lkml.kernel.org/r/20190617130014.1713870-1-arnd@arndb.de [akpm@linux-foundation.org: fix fs/eventpoll.c] Link: http://lkml.kernel.org/r/20190430180111.10688-1-mcroce@redhat.com Signed-off-by: Matteo Croce <mcroce@redhat.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Kees Cook <keescook@chromium.org> Reviewed-by: Aaron Tomlin <atomlin@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | ipc/mqueue.c: only perform resource calculation if user validKees Cook2019-07-161-9/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Andreas Christoforou reported: UBSAN: Undefined behaviour in ipc/mqueue.c:414:49 signed integer overflow: 9 * 2305843009213693951 cannot be represented in type 'long int' ... Call Trace: mqueue_evict_inode+0x8e7/0xa10 ipc/mqueue.c:414 evict+0x472/0x8c0 fs/inode.c:558 iput_final fs/inode.c:1547 [inline] iput+0x51d/0x8c0 fs/inode.c:1573 mqueue_get_inode+0x8eb/0x1070 ipc/mqueue.c:320 mqueue_create_attr+0x198/0x440 ipc/mqueue.c:459 vfs_mkobj+0x39e/0x580 fs/namei.c:2892 prepare_open ipc/mqueue.c:731 [inline] do_mq_open+0x6da/0x8e0 ipc/mqueue.c:771 Which could be triggered by: struct mq_attr attr = { .mq_flags = 0, .mq_maxmsg = 9, .mq_msgsize = 0x1fffffffffffffff, .mq_curmsgs = 0, }; if (mq_open("/testing", 0x40, 3, &attr) == (mqd_t) -1) perror("mq_open"); mqueue_get_inode() was correctly rejecting the giant mq_msgsize, and preparing to return -EINVAL. During the cleanup, it calls mqueue_evict_inode() which performed resource usage tracking math for updating "user", before checking if there was a valid "user" at all (which would indicate that the calculations would be sane). Instead, delay this check to after seeing a valid "user". The overflow was real, but the results went unused, so while the flaw is harmless, it's noisy for kernel fuzzers, so just fix it by moving the calculation under the non-NULL "user" where it actually gets used. Link: http://lkml.kernel.org/r/201906072207.ECB65450@keescook Signed-off-by: Kees Cook <keescook@chromium.org> Reported-by: Andreas Christoforou <andreaschristofo@gmail.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441Thomas Gleixner2019-06-052-10/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation version 2 of the license extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 315 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Armijn Hemel <armijn@tjaldur.nl> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190531190115.503150771@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 52Thomas Gleixner2019-05-241-5/+1
|/ | | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this file is released under gnu general public licence version 2 or at your option any later version see the file copying for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520071857.941092988@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ipc: do cyclic id allocation for the ipc object.Manfred Spraul2019-05-143-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For ipcmni_extend mode, the sequence number space is only 7 bits. So the chance of id reuse is relatively high compared with the non-extended mode. To alleviate this id reuse problem, this patch enables cyclic allocation for the index to the radix tree (idx). The disadvantage is that this can cause a slight slow-down of the fast path, as the radix tree could be higher than necessary. To limit the radix tree height, I have chosen the following limits: 1) The cycling is done over in_use*1.5. 2) At least, the cycling is done over "normal" ipcnmi mode: RADIX_TREE_MAP_SIZE elements "ipcmni_extended": 4096 elements Result: - for normal mode: No change for <= 42 active ipc elements. With more than 42 active ipc elements, a 2nd level would be added to the radix tree. Without cyclic allocation, a 2nd level would be added only with more than 63 active elements. - for extended mode: Cycling creates always at least a 2-level radix tree. With more than 2730 active objects, a 3rd level would be added, instead of > 4095 active objects until the 3rd level is added without cyclic allocation. For a 2-level radix tree compared to a 1-level radix tree, I have observed < 1% performance impact. Notes: 1) Normal "x=semget();y=semget();" is unaffected: Then the idx is e.g. a and a+1, regardless if idr_alloc() or idr_alloc_cyclic() is used. 2) The -1% happens in a microbenchmark after this situation: x=semget(); for(i=0;i<4000;i++) {t=semget();semctl(t,0,IPC_RMID);} y=semget(); Now perform semget calls on x and y that do not sleep. 3) The worst-case reuse cycle time is unfortunately unaffected: If you have 2^24-1 ipc objects allocated, and get/remove the last possible element in a loop, then the id is reused after 128 get/remove pairs. Performance check: A microbenchmark that performes no-op semop() randomly on two IDs, with only these two IDs allocated. The IDs were set using /proc/sys/kernel/sem_next_id. The test was run 5 times, averages are shown. 1 & 2: Base (6.22 seconds for 10.000.000 semops) 1 & 40: -0.2% 1 & 3348: - 0.8% 1 & 27348: - 1.6% 1 & 15777204: - 3.2% Or: ~12.6 cpu cycles per additional radix tree level. The cpu is an Intel I3-5010U. ~1300 cpu cycles/syscall is slower than what I remember (spectre impact?). V2 of the patch: - use "min" and "max" - use RADIX_TREE_MAP_SIZE * RADIX_TREE_MAP_SIZE instead of (2<<12). [akpm@linux-foundation.org: fix max() warning] Link: http://lkml.kernel.org/r/20190329204930.21620-3-longman@redhat.com Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Acked-by: Waiman Long <longman@redhat.com> Cc: "Luis R. Rodriguez" <mcgrof@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Matthew Wilcox <willy@infradead.org> Cc: "Eric W . Biederman" <ebiederm@xmission.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: conserve sequence numbers in ipcmni_extend modeManfred Spraul2019-05-142-9/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rewrite, based on the patch from Waiman Long: The mixing in of a sequence number into the IPC IDs is probably to avoid ID reuse in userspace as much as possible. With ipcmni_extend mode, the number of usable sequence numbers is greatly reduced leading to higher chance of ID reuse. To address this issue, we need to conserve the sequence number space as much as possible. Right now, the sequence number is incremented for every new ID created. In reality, we only need to increment the sequence number when new allocated ID is not greater than the last one allocated. It is in such case that the new ID may collide with an existing one. This is being done irrespective of the ipcmni mode. In order to avoid any races, the index is first allocated and then the pointer is replaced. Changes compared to the initial patch: - Handle failures from idr_alloc(). - Avoid that concurrent operations can see the wrong sequence number. (This is achieved by using idr_replace()). - IPCMNI_SEQ_SHIFT is not a constant, thus renamed to ipcmni_seq_shift(). - IPCMNI_SEQ_MAX is not a constant, thus renamed to ipcmni_seq_max(). Link: http://lkml.kernel.org/r/20190329204930.21620-2-longman@redhat.com Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Waiman Long <longman@redhat.com> Suggested-by: Matthew Wilcox <willy@infradead.org> Acked-by: Waiman Long <longman@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: "Eric W . Biederman" <ebiederm@xmission.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kees Cook <keescook@chromium.org> Cc: "Luis R. Rodriguez" <mcgrof@kernel.org> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: allow boot time extension of IPCMNI from 32k to 16MWaiman Long2019-05-143-15/+51
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The maximum number of unique System V IPC identifiers was limited to 32k. That limit should be big enough for most use cases. However, there are some users out there requesting for more, especially those that are migrating from Solaris which uses 24 bits for unique identifiers. To satisfy the need of those users, a new boot time kernel option "ipcmni_extend" is added to extend the IPCMNI value to 16M. This is a 512X increase which should be big enough for users out there that need a large number of unique IPC identifier. The use of this new option will change the pattern of the IPC identifiers returned by functions like shmget(2). An application that depends on such pattern may not work properly. So it should only be used if the users really need more than 32k of unique IPC numbers. This new option does have the side effect of reducing the maximum number of unique sequence numbers from 64k down to 128. So it is a trade-off. The computation of a new IPC id is not done in the performance critical path. So a little bit of additional overhead shouldn't have any real performance impact. Link: http://lkml.kernel.org/r/20190329204930.21620-1-longman@redhat.com Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Manfred Spraul <manfred@colorfullife.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: "Eric W . Biederman" <ebiederm@xmission.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kees Cook <keescook@chromium.org> Cc: "Luis R. Rodriguez" <mcgrof@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/mqueue: optimize msg_get()Davidlohr Bueso2019-05-141-25/+35
| | | | | | | | | | | | | | | | | | | Our msg priorities became an rbtree as of d6629859b36d ("ipc/mqueue: improve performance of send/recv"). However, consuming a msg in msg_get() remains logarithmic (still being better than the case before of course). By applying well known techniques to cache pointers we can have the node with the highest priority in O(1), which is specially nice for the rt cases. Furthermore, some callers can call msg_get() in a loop. A new msg_tree_erase() helper is also added to encapsulate the tree removal and node_cache game. Passes ltp mq testcases. Link: http://lkml.kernel.org/r/20190321190216.1719-2-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/mqueue: remove redundant wq task assignmentDavidlohr Bueso2019-05-141-2/+0
| | | | | | | | | | | | We already store the current task fo the new waiter before calling wq_sleep() in both send and recv paths. Trivially remove the redundant assignment. Link: http://lkml.kernel.org/r/20190321190216.1719-1-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: prevent lockup on alloc_msg and free_msgLi Rongqing2019-05-142-2/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | msgctl10 of ltp triggers the following lockup When CONFIG_KASAN is enabled on large memory SMP systems, the pages initialization can take a long time, if msgctl10 requests a huge block memory, and it will block rcu scheduler, so release cpu actively. After adding schedule() in free_msg, free_msg can not be called when holding spinlock, so adding msg to a tmp list, and free it out of spinlock rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-1 rcu_node (CPUs 16-31): P32505 rcu: Tasks blocked on level-1 rcu_node (CPUs 48-63): P34978 rcu: (detected by 11, t=35024 jiffies, g=44237529, q=16542267) msgctl10 R running task 21608 32505 2794 0x00000082 Call Trace: preempt_schedule_irq+0x4c/0xb0 retint_kernel+0x1b/0x2d RIP: 0010:__is_insn_slot_addr+0xfb/0x250 Code: 82 1d 00 48 8b 9b 90 00 00 00 4c 89 f7 49 c1 ee 03 e8 59 83 1d 00 48 b8 00 00 00 00 00 fc ff df 4c 39 eb 48 89 9d 58 ff ff ff <41> c6 04 06 f8 74 66 4c 8d 75 98 4c 89 f1 48 c1 e9 03 48 01 c8 48 RSP: 0018:ffff88bce041f758 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: dffffc0000000000 RBX: ffffffff8471bc50 RCX: ffffffff828a2a57 RDX: dffffc0000000000 RSI: dffffc0000000000 RDI: ffff88bce041f780 RBP: ffff88bce041f828 R08: ffffed15f3f4c5b3 R09: ffffed15f3f4c5b3 R10: 0000000000000001 R11: ffffed15f3f4c5b2 R12: 000000318aee9b73 R13: ffffffff8471bc50 R14: 1ffff1179c083ef0 R15: 1ffff1179c083eec kernel_text_address+0xc1/0x100 __kernel_text_address+0xe/0x30 unwind_get_return_address+0x2f/0x50 __save_stack_trace+0x92/0x100 create_object+0x380/0x650 __kmalloc+0x14c/0x2b0 load_msg+0x38/0x1a0 do_msgsnd+0x19e/0xcf0 do_syscall_64+0x117/0x400 entry_SYSCALL_64_after_hwframe+0x49/0xbe rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-1 rcu_node (CPUs 0-15): P32170 rcu: (detected by 14, t=35016 jiffies, g=44237525, q=12423063) msgctl10 R running task 21608 32170 32155 0x00000082 Call Trace: preempt_schedule_irq+0x4c/0xb0 retint_kernel+0x1b/0x2d RIP: 0010:lock_acquire+0x4d/0x340 Code: 48 81 ec c0 00 00 00 45 89 c6 4d 89 cf 48 8d 6c 24 20 48 89 3c 24 48 8d bb e4 0c 00 00 89 74 24 0c 48 c7 44 24 20 b3 8a b5 41 <48> c1 ed 03 48 c7 44 24 28 b4 25 18 84 48 c7 44 24 30 d0 54 7a 82 RSP: 0018:ffff88af83417738 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 RAX: dffffc0000000000 RBX: ffff88bd335f3080 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88bd335f3d64 RBP: ffff88af83417758 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: ffffed13f3f745b2 R12: 0000000000000000 R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000000 is_bpf_text_address+0x32/0xe0 kernel_text_address+0xec/0x100 __kernel_text_address+0xe/0x30 unwind_get_return_address+0x2f/0x50 __save_stack_trace+0x92/0x100 save_stack+0x32/0xb0 __kasan_slab_free+0x130/0x180 kfree+0xfa/0x2d0 free_msg+0x24/0x50 do_msgrcv+0x508/0xe60 do_syscall_64+0x117/0x400 entry_SYSCALL_64_after_hwframe+0x49/0xbe Davidlohr said: "So after releasing the lock, the msg rbtree/list is empty and new calls will not see those in the newly populated tmp_msg list, and therefore they cannot access the delayed msg freeing pointers, which is good. Also the fact that the node_cache is now freed before the actual messages seems to be harmless as this is wanted for msg_insert() avoiding GFP_ATOMIC allocations, and after releasing the info->lock the thing is freed anyway so it should not change things" Link: http://lkml.kernel.org/r/1552029161-4957-1-git-send-email-lirongqing@baidu.com Signed-off-by: Li RongQing <lirongqing@baidu.com> Signed-off-by: Zhang Yu <zhangyu31@baidu.com> Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-nextLinus Torvalds2019-05-071-1/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull networking updates from David Miller: "Highlights: 1) Support AES128-CCM ciphers in kTLS, from Vakul Garg. 2) Add fib_sync_mem to control the amount of dirty memory we allow to queue up between synchronize RCU calls, from David Ahern. 3) Make flow classifier more lockless, from Vlad Buslov. 4) Add PHY downshift support to aquantia driver, from Heiner Kallweit. 5) Add SKB cache for TCP rx and tx, from Eric Dumazet. This reduces contention on SLAB spinlocks in heavy RPC workloads. 6) Partial GSO offload support in XFRM, from Boris Pismenny. 7) Add fast link down support to ethtool, from Heiner Kallweit. 8) Use siphash for IP ID generator, from Eric Dumazet. 9) Pull nexthops even further out from ipv4/ipv6 routes and FIB entries, from David Ahern. 10) Move skb->xmit_more into a per-cpu variable, from Florian Westphal. 11) Improve eBPF verifier speed and increase maximum program size, from Alexei Starovoitov. 12) Eliminate per-bucket spinlocks in rhashtable, and instead use bit spinlocks. From Neil Brown. 13) Allow tunneling with GUE encap in ipvs, from Jacky Hu. 14) Improve link partner cap detection in generic PHY code, from Heiner Kallweit. 15) Add layer 2 encap support to bpf_skb_adjust_room(), from Alan Maguire. 16) Remove SKB list implementation assumptions in SCTP, your's truly. 17) Various cleanups, optimizations, and simplifications in r8169 driver. From Heiner Kallweit. 18) Add memory accounting on TX and RX path of SCTP, from Xin Long. 19) Switch PHY drivers over to use dynamic featue detection, from Heiner Kallweit. 20) Support flow steering without masking in dpaa2-eth, from Ioana Ciocoi. 21) Implement ndo_get_devlink_port in netdevsim driver, from Jiri Pirko. 22) Increase the strict parsing of current and future netlink attributes, also export such policies to userspace. From Johannes Berg. 23) Allow DSA tag drivers to be modular, from Andrew Lunn. 24) Remove legacy DSA probing support, also from Andrew Lunn. 25) Allow ll_temac driver to be used on non-x86 platforms, from Esben Haabendal. 26) Add a generic tracepoint for TX queue timeouts to ease debugging, from Cong Wang. 27) More indirect call optimizations, from Paolo Abeni" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1763 commits) cxgb4: Fix error path in cxgb4_init_module net: phy: improve pause mode reporting in phy_print_status dt-bindings: net: Fix a typo in the phy-mode list for ethernet bindings net: macb: Change interrupt and napi enable order in open net: ll_temac: Improve error message on error IRQ net/sched: remove block pointer from common offload structure net: ethernet: support of_get_mac_address new ERR_PTR error net: usb: smsc: fix warning reported by kbuild test robot staging: octeon-ethernet: Fix of_get_mac_address ERR_PTR check net: dsa: support of_get_mac_address new ERR_PTR error net: dsa: sja1105: Fix status initialization in sja1105_get_ethtool_stats vrf: sit mtu should not be updated when vrf netdev is the link net: dsa: Fix error cleanup path in dsa_init_module l2tp: Fix possible NULL pointer dereference taprio: add null check on sched_nest to avoid potential null pointer dereference net: mvpp2: cls: fix less than zero check on a u32 variable net_sched: sch_fq: handle non connected flows net_sched: sch_fq: do not assume EDT packets are ordered net: hns3: use devm_kcalloc when allocating desc_cb net: hns3: some cleanup for struct hns3_enet_ring ...
| * rhashtable: use bit_spin_locks to protect hash bucket.NeilBrown2019-04-071-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch changes rhashtables to use a bit_spin_lock on BIT(1) of the bucket pointer to lock the hash chain for that bucket. The benefits of a bit spin_lock are: - no need to allocate a separate array of locks. - no need to have a configuration option to guide the choice of the size of this array - locking cost is often a single test-and-set in a cache line that will have to be loaded anyway. When inserting at, or removing from, the head of the chain, the unlock is free - writing the new address in the bucket head implicitly clears the lock bit. For __rhashtable_insert_fast() we ensure this always happens when adding a new key. - even when lockings costs 2 updates (lock and unlock), they are in a cacheline that needs to be read anyway. The cost of using a bit spin_lock is a little bit of code complexity, which I think is quite manageable. Bit spin_locks are sometimes inappropriate because they are not fair - if multiple CPUs repeatedly contend of the same lock, one CPU can easily be starved. This is not a credible situation with rhashtable. Multiple CPUs may want to repeatedly add or remove objects, but they will typically do so at different buckets, so they will attempt to acquire different locks. As we have more bit-locks than we previously had spinlocks (by at least a factor of two) we can expect slightly less contention to go with the slightly better cache behavior and reduced memory consumption. To enhance type checking, a new struct is introduced to represent the pointer plus lock-bit that is stored in the bucket-table. This is "struct rhash_lock_head" and is empty. A pointer to this needs to be cast to either an unsigned lock, or a "struct rhash_head *" to be useful. Variables of this type are most often called "bkt". Previously "pprev" would sometimes point to a bucket, and sometimes a ->next pointer in an rhash_head. As these are now different types, pprev is NULL when it would have pointed to the bucket. In that case, 'blk' is used, together with correct locking protocol. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | mqueue: switch to ->free_inode()Al Viro2019-05-011-8/+2
|/ | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'work.mount' of ↵Linus Torvalds2019-03-122-23/+73
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs mount infrastructure updates from Al Viro: "The rest of core infrastructure; no new syscalls in that pile, but the old parts are switched to new infrastructure. At that point conversions of individual filesystems can happen independently; some are done here (afs, cgroup, procfs, etc.), there's also a large series outside of that pile dealing with NFS (quite a bit of option-parsing stuff is getting used there - it's one of the most convoluted filesystems in terms of mount-related logics), but NFS bits are the next cycle fodder. It got seriously simplified since the last cycle; documentation is probably the weakest bit at the moment - I considered dropping the commit introducing Documentation/filesystems/mount_api.txt (cutting the size increase by quarter ;-), but decided that it would be better to fix it up after -rc1 instead. That pile allows to do followup work in independent branches, which should make life much easier for the next cycle. fs/super.c size increase is unpleasant; there's a followup series that allows to shrink it considerably, but I decided to leave that until the next cycle" * 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (41 commits) afs: Use fs_context to pass parameters over automount afs: Add fs_context support vfs: Add some logging to the core users of the fs_context log vfs: Implement logging through fs_context vfs: Provide documentation for new mount API vfs: Remove kern_mount_data() hugetlbfs: Convert to fs_context cpuset: Use fs_context kernfs, sysfs, cgroup, intel_rdt: Support fs_context cgroup: store a reference to cgroup_ns into cgroup_fs_context cgroup1_get_tree(): separate "get cgroup_root to use" into a separate helper cgroup_do_mount(): massage calling conventions cgroup: stash cgroup_root reference into cgroup_fs_context cgroup2: switch to option-by-option parsing cgroup1: switch to option-by-option parsing cgroup: take options parsing into ->parse_monolithic() cgroup: fold cgroup1_mount() into cgroup1_get_tree() cgroup: start switching to fs_context ipc: Convert mqueue fs to fs_context proc: Add fs_context support to procfs ...
| * ipc: Convert mqueue fs to fs_contextDavid Howells2019-02-282-23/+73
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Convert the mqueue filesystem to use the filesystem context stuff. Notes: (1) The relevant ipc namespace is selected in when the context is initialised (and it defaults to the current task's ipc namespace). The caller can override this before calling vfs_get_tree(). (2) Rather than simply calling kern_mount_data(), mq_init_ns() and mq_internal_mount() create a context, adjust it and then do the rest of the mount procedure. (3) The lazy mqueue mounting on creation of a new namespace is retained from a previous patch, but the avoidance of sget() if no superblock yet exists is reverted and the superblock is again keyed on the namespace pointer. Yes, there was a performance gain in not searching the superblock hash, but it's only paid once per ipc namespace - and only if someone uses mqueue within that namespace, so I'm not sure it's worth it, especially as calling sget() allows avoidance of recursion. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | ipc/sem.c: replace kvmalloc/memset with kvzalloc and use struct_sizeGustavo A. R. Silva2019-03-071-5/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use kvzalloc() instead of kvmalloc() and memset(). Also, make use of the struct_size() helper instead of the open-coded version in order to avoid any potential type mistakes. This code was detected with the help of Coccinelle. Link: http://lkml.kernel.org/r/20190131214221.GA28930@embeddedor Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | ipc: annotate implicit fall throughMathieu Malaterre2019-03-071-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is a plan to build the kernel with -Wimplicit-fallthrough and this place in the code produced a warning (W=1). This commit remove the following warning: ipc/sem.c:1683:6: warning: this statement may fall through [-Wimplicit-fallthrough=] Link: http://lkml.kernel.org/r/20190114203608.18218-1-malat@debian.org Signed-off-by: Mathieu Malaterre <malat@debian.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | y2038: syscalls: rename y2038 compat syscallsArnd Bergmann2019-02-072-9/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A lot of system calls that pass a time_t somewhere have an implementation using a COMPAT_SYSCALL_DEFINEx() on 64-bit architectures, and have been reworked so that this implementation can now be used on 32-bit architectures as well. The missing step is to redefine them using the regular SYSCALL_DEFINEx() to get them out of the compat namespace and make it possible to build them on 32-bit architectures. Any system call that ends in 'time' gets a '32' suffix on its name for that version, while the others get a '_time32' suffix, to distinguish them from the normal version, which takes a 64-bit time argument in the future. In this step, only 64-bit architectures are changed, doing this rename first lets us avoid touching the 32-bit architectures twice. Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
* | ipc: rename old-style shmctl/semctl/msgctl syscallsArnd Bergmann2019-01-255-41/+110
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The behavior of these system calls is slightly different between architectures, as determined by the CONFIG_ARCH_WANT_IPC_PARSE_VERSION symbol. Most architectures that implement the split IPC syscalls don't set that symbol and only get the modern version, but alpha, arm, microblaze, mips-n32, mips-n64 and xtensa expect the caller to pass the IPC_64 flag. For the architectures that so far only implement sys_ipc(), i.e. m68k, mips-o32, powerpc, s390, sh, sparc, and x86-32, we want the new behavior when adding the split syscalls, so we need to distinguish between the two groups of architectures. The method I picked for this distinction is to have a separate system call entry point: sys_old_*ctl() now uses ipc_parse_version, while sys_*ctl() does not. The system call tables of the five architectures are changed accordingly. As an additional benefit, we no longer need the configuration specific definition for ipc_parse_version(), it always does the same thing now, but simply won't get called on architectures with the modern interface. A small downside is that on architectures that do set ARCH_WANT_IPC_PARSE_VERSION, we now have an extra set of entry points that are never called. They only add a few bytes of bloat, so it seems better to keep them compared to adding yet another Kconfig symbol. I considered adding new syscall numbers for the IPC_64 variants for consistency, but decided against that for now. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
* | ipc: introduce ksys_ipc()/compat_ksys_ipc() for s390Arnd Bergmann2019-01-181-4/+16
|/ | | | | | | | | | | | | | | The sys_ipc() and compat_ksys_ipc() functions are meant to only be used from the system call table, not called by another function. Introduce ksys_*() interfaces for this purpose, as we have done for many other system calls. Link: https://lore.kernel.org/lkml/20190116131527.2071570-3-arnd@arndb.de Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> [heiko.carstens@de.ibm.com: compile fix for !CONFIG_COMPAT] Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* ipc: IPCMNI limit check for semmniWaiman Long2018-10-312-1/+31
| | | | | | | | | | | | | | | | | | | | | For SysV semaphores, the semmni value is the last part of the 4-element sem number array. To make semmni behave in a similar way to msgmni and shmmni, we can't directly use the _minmax handler. Instead, a special sem specific handler is added to check the last argument to make sure that it is limited to the [0, IPCMNI] range. An error will be returned if this is not the case. Link: http://lkml.kernel.org/r/1536352137-12003-3-git-send-email-longman@redhat.com Signed-off-by: Waiman Long <longman@redhat.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kees Cook <keescook@chromium.org> Cc: Luis R. Rodriguez <mcgrof@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: IPCMNI limit check for msgmni and shmmniWaiman Long2018-10-311-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "ipc: IPCMNI limit check for *mni & increase that limit", v9. The sysctl parameters msgmni, shmmni and semmni have an inherent limit of IPC_MNI (32k). However, users may not be aware of that because they can write a value much higher than that without getting any error or notification. Reading the parameters back will show the newly written values which are not real. The real IPCMNI limit is now enforced to make sure that users won't put in an unrealistic value. The first 2 patches enforce the limits. There are also users out there requesting increase in the IPCMNI value. The last 2 patches attempt to do that by using a boot kernel parameter "ipcmni_extend" to increase the IPCMNI limit from 32k to 8M if the users really want the extended value. This patch (of 4): A user can write arbitrary integer values to msgmni and shmmni sysctl parameters without getting error, but the actual limit is really IPCMNI (32k). This can mislead users as they think they can get a value that is not real. The right limits are now set for msgmni and shmmni so that the users will become aware if they set a value outside of the acceptable range. Link: http://lkml.kernel.org/r/1536352137-12003-2-git-send-email-longman@redhat.com Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Luis R. Rodriguez <mcgrof@kernel.org> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox <willy@infradead.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'timers-core-for-linus' of ↵Linus Torvalds2018-10-256-17/+17
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timekeeping updates from Thomas Gleixner: "The timers and timekeeping departement provides: - Another large y2038 update with further preparations for providing the y2038 safe timespecs closer to the syscalls. - An overhaul of the SHCMT clocksource driver - SPDX license identifier updates - Small cleanups and fixes all over the place" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits) tick/sched : Remove redundant cpu_online() check clocksource/drivers/dw_apb: Add reset control clocksource: Remove obsolete CLOCKSOURCE_OF_DECLARE clocksource/drivers: Unify the names to timer-* format clocksource/drivers/sh_cmt: Add R-Car gen3 support dt-bindings: timer: renesas: cmt: document R-Car gen3 support clocksource/drivers/sh_cmt: Properly line-wrap sh_cmt_of_table[] initializer clocksource/drivers/sh_cmt: Fix clocksource width for 32-bit machines clocksource/drivers/sh_cmt: Fixup for 64-bit machines clocksource/drivers/sh_tmu: Convert to SPDX identifiers clocksource/drivers/sh_mtu2: Convert to SPDX identifiers clocksource/drivers/sh_cmt: Convert to SPDX identifiers clocksource/drivers/renesas-ostm: Convert to SPDX identifiers clocksource: Convert to using %pOFn instead of device_node.name tick/broadcast: Remove redundant check RISC-V: Request newstat syscalls y2038: signal: Change rt_sigtimedwait to use __kernel_timespec y2038: socket: Change recvmmsg to use __kernel_timespec y2038: sched: Change sched_rr_get_interval to use __kernel_timespec y2038: utimes: Rework #ifdef guards for compat syscalls ...
| * y2038: globally rename compat_time to old_time32Arnd Bergmann2018-08-276-17/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Christoph Hellwig suggested a slightly different path for handling backwards compatibility with the 32-bit time_t based system calls: Rather than simply reusing the compat_sys_* entry points on 32-bit architectures unchanged, we get rid of those entry points and the compat_time types by renaming them to something that makes more sense on 32-bit architectures (which don't have a compat mode otherwise), and then share the entry points under the new name with the 64-bit architectures that use them for implementing the compatibility. The following types and interfaces are renamed here, and moved from linux/compat_time.h to linux/time32.h: old new --- --- compat_time_t old_time32_t struct compat_timeval struct old_timeval32 struct compat_timespec struct old_timespec32 struct compat_itimerspec struct old_itimerspec32 ns_to_compat_timeval() ns_to_old_timeval32() get_compat_itimerspec64() get_old_itimerspec32() put_compat_itimerspec64() put_old_itimerspec32() compat_get_timespec64() get_old_timespec32() compat_put_timespec64() put_old_timespec32() As we already have aliases in place, this patch addresses only the instances that are relevant to the system call interface in particular, not those that occur in device drivers and other modules. Those will get handled separately, while providing the 64-bit version of the respective interfaces. I'm not renaming the timex, rusage and itimerval structures, as we are still debating what the new interface will look like, and whether we will need a replacement at all. This also doesn't change the names of the syscall entry points, which can be done more easily when we actually switch over the 32-bit architectures to use them, at that point we need to change COMPAT_SYSCALL_DEFINEx to SYSCALL_DEFINEx with a new name, e.g. with a _time32 suffix. Suggested-by: Christoph Hellwig <hch@infradead.org> Link: https://lore.kernel.org/lkml/20180705222110.GA5698@infradead.org/ Signed-off-by: Arnd Bergmann <arnd@arndb.de>
* | Merge branch 'siginfo-linus' of ↵Linus Torvalds2018-10-241-1/+1
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull siginfo updates from Eric Biederman: "I have been slowly sorting out siginfo and this is the culmination of that work. The primary result is in several ways the signal infrastructure has been made less error prone. The code has been updated so that manually specifying SEND_SIG_FORCED is never necessary. The conversion to the new siginfo sending functions is now complete, which makes it difficult to send a signal without filling in the proper siginfo fields. At the tail end of the patchset comes the optimization of decreasing the size of struct siginfo in the kernel from 128 bytes to about 48 bytes on 64bit. The fundamental observation that enables this is by definition none of the known ways to use struct siginfo uses the extra bytes. This comes at the cost of a small user space observable difference. For the rare case of siginfo being injected into the kernel only what can be copied into kernel_siginfo is delivered to the destination, the rest of the bytes are set to 0. For cases where the signal and the si_code are known this is safe, because we know those bytes are not used. For cases where the signal and si_code combination is unknown the bits that won't fit into struct kernel_siginfo are tested to verify they are zero, and the send fails if they are not. I made an extensive search through userspace code and I could not find anything that would break because of the above change. If it turns out I did break something it will take just the revert of a single change to restore kernel_siginfo to the same size as userspace siginfo. Testing did reveal dependencies on preferring the signo passed to sigqueueinfo over si->signo, so bit the bullet and added the complexity necessary to handle that case. Testing also revealed bad things can happen if a negative signal number is passed into the system calls. Something no sane application will do but something a malicious program or a fuzzer might do. So I have fixed the code that performs the bounds checks to ensure negative signal numbers are handled" * 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (80 commits) signal: Guard against negative signal numbers in copy_siginfo_from_user32 signal: Guard against negative signal numbers in copy_siginfo_from_user signal: In sigqueueinfo prefer sig not si_signo signal: Use a smaller struct siginfo in the kernel signal: Distinguish between kernel_siginfo and siginfo signal: Introduce copy_siginfo_from_user and use it's return value signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE signal: Fail sigqueueinfo if si_signo != sig signal/sparc: Move EMT_TAGOVF into the generic siginfo.h signal/unicore32: Use force_sig_fault where appropriate signal/unicore32: Generate siginfo in ucs32_notify_die signal/unicore32: Use send_sig_fault where appropriate signal/arc: Use force_sig_fault where appropriate signal/arc: Push siginfo generation into unhandled_exception signal/ia64: Use force_sig_fault where appropriate signal/ia64: Use the force_sig(SIGSEGV,...) in ia64_rt_sigreturn signal/ia64: Use the generic force_sigsegv in setup_frame signal/arm/kvm: Use send_sig_mceerr signal/arm: Use send_sig_fault where appropriate signal/arm: Use force_sig_fault where appropriate ...
| * | signal: Distinguish between kernel_siginfo and siginfoEric W. Biederman2018-10-031-1/+1
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Linus recently observed that if we did not worry about the padding member in struct siginfo it is only about 48 bytes, and 48 bytes is much nicer than 128 bytes for allocating on the stack and copying around in the kernel. The obvious thing of only adding the padding when userspace is including siginfo.h won't work as there are sigframe definitions in the kernel that embed struct siginfo. So split siginfo in two; kernel_siginfo and siginfo. Keeping the traditional name for the userspace definition. While the version that is used internally to the kernel and ultimately will not be padded to 128 bytes is called kernel_siginfo. The definition of struct kernel_siginfo I have put in include/signal_types.h A set of buildtime checks has been added to verify the two structures have the same field offsets. To make it easy to verify the change kernel_siginfo retains the same size as siginfo. The reduction in size comes in a following change. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* | ipc/shm.c: use ERR_CAST() for shm_lock() error returnKees Cook2018-10-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This uses ERR_CAST() instead of an open-coded cast, as it is casting across structure pointers, which upsets __randomize_layout: ipc/shm.c: In function `shm_lock': ipc/shm.c:209:9: note: randstruct: casting between randomized structure pointer types (ssa): `struct shmid_kernel' and `struct kern_ipc_perm' return (void *)ipcp; ^~~~~~~~~~~~ Link: http://lkml.kernel.org/r/20180919180722.GA15073@beast Fixes: 82061c57ce93 ("ipc: drop ipc_lock()") Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | ipc/shm: properly return EIDRM in shm_lock()Davidlohr Bueso2018-09-041-0/+1
|/ | | | | | | | | | | | | | | | When getting rid of the general ipc_lock(), this was missed furthermore, making the comment around the ipc object validity check bogus. Under EIDRM conditions, callers will in turn not see the error and continue with the operation. Link: http://lkml.kernel.org/r/20180824030920.GD3677@linux-r8p5 Link: http://lkml.kernel.org/r/20180823024051.GC13343@shao2-debian Fixes: 82061c57ce9 ("ipc: drop ipc_lock()") Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Reported-by: kernel test robot <rong.a.chen@intel.com> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/util.c: update return value of ipc_getref from int to boolManfred Spraul2018-08-222-2/+2
| | | | | | | | | | | | | | | | | | | | | | ipc_getref has still a return value of type "int", matching the atomic_t interface of atomic_inc_not_zero()/atomic_add_unless(). ipc_getref now uses refcount_inc_not_zero, which has a return value of type "bool". Therefore, update the return code to avoid implicit conversions. Link: http://lkml.kernel.org/r/20180712185241.4017-13-manfred@colorfullife.com Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Kees Cook <keescook@chromium.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/util.c: further variable name cleanupsManfred Spraul2018-08-225-26/+26
| | | | | | | | | | | | | | | | | | | | | | | | The varable names got a mess, thus standardize them again: id: user space id. Called semid, shmid, msgid if the type is known. Most functions use "id" already. idx: "index" for the idr lookup Right now, some functions use lid, ipc_addid() already uses idx as the variable name. seq: sequence number, to avoid quick collisions of the user space id key: user space key, used for the rhash tree Link: http://lkml.kernel.org/r/20180712185241.4017-12-manfred@colorfullife.com Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Kees Cook <keescook@chromium.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: simplify ipc initializationDavidlohr Bueso2018-08-226-54/+30
| | | | | | | | | | | | | | | | | Now that we know that rhashtable_init() will not fail, we can get rid of a lot of the unnecessary cleanup paths when the call errored out. [manfred@colorfullife.com: variable name added to util.h to resolve checkpatch warning] Link: http://lkml.kernel.org/r/20180712185241.4017-11-manfred@colorfullife.com Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Kees Cook <keescook@chromium.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: get rid of ids->tables_initialized hackDavidlohr Bueso2018-08-221-15/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In sysvipc we have an ids->tables_initialized regarding the rhashtable, introduced in 0cfb6aee70bd ("ipc: optimize semget/shmget/msgget for lots of keys") It's there, specifically, to prevent nil pointer dereferences, from using an uninitialized api. Considering how rhashtable_init() can fail (probably due to ENOMEM, if anything), this made the overall ipc initialization capable of failure as well. That alone is ugly, but fine, however I've spotted a few issues regarding the semantics of tables_initialized (however unlikely they may be): - There is inconsistency in what we return to userspace: ipc_addid() returns ENOSPC which is certainly _wrong_, while ipc_obtain_object_idr() returns EINVAL. - After we started using rhashtables, ipc_findkey() can return nil upon !tables_initialized, but the caller expects nil for when the ipc structure isn't found, and can therefore call into ipcget() callbacks. Now that rhashtable initialization cannot fail, we can properly get rid of the hack altogether. [manfred@colorfullife.com: commit id extended to 12 digits] Link: http://lkml.kernel.org/r/20180712185241.4017-10-manfred@colorfullife.com Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Kees Cook <keescook@chromium.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: drop ipc_lock()Davidlohr Bueso2018-08-223-43/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ipc/util.c contains multiple functions to get the ipc object pointer given an id number. There are two sets of function: One set verifies the sequence counter part of the id number, other functions do not check the sequence counter. The standard for function names in ipc/util.c is - ..._check() functions verify the sequence counter - ..._idr() functions do not verify the sequence counter ipc_lock() is an exception: It does not verify the sequence counter value, but this is not obvious from the function name. Furthermore, shm.c is the only user of this helper. Thus, we can simply move the logic into shm_lock() and get rid of the function altogether. [manfred@colorfullife.com: most of changelog] Link: http://lkml.kernel.org/r/20180712185241.4017-7-manfred@colorfullife.com Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Kees Cook <keescook@chromium.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/util.c: correct comment in ipc_obtain_object_checkManfred Spraul2018-08-221-2/+2
| | | | | | | | | | | | | | | | | | | | | | The comment that explains ipc_obtain_object_check is wrong: The function checks the sequence number, not the reference counter. Note that checking the reference counter would be meaningless: The reference counter is decreased without holding any locks, thus an object with kern_ipc_perm.deleted=true may disappear at the end of the next rcu grace period. Link: http://lkml.kernel.org/r/20180712185241.4017-6-manfred@colorfullife.com Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Kees Cook <keescook@chromium.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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