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2009-05-06inotify: use GFP_NOFS in kernel_event() to work around a lockdep false-positiveWu Fengguang
There is what we believe to be a false positive reported by lockdep. inotify_inode_queue_event() => take inotify_mutex => kernel_event() => kmalloc() => SLOB => alloc_pages_node() => page reclaim => slab reclaim => dcache reclaim => inotify_inode_is_dead => take inotify_mutex => deadlock The plan is to fix this via lockdep annotation, but that is proving to be quite involved. The patch flips the allocation over to GFP_NFS to shut the warning up, for the 2.6.30 release. Hopefully we will fix this for real in 2.6.31. I'll queue a patch in -mm to switch it back to GFP_KERNEL so we don't forget. ================================= [ INFO: inconsistent lock state ] 2.6.30-rc2-next-20090417 #203 --------------------------------- inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage. kswapd0/380 [HC0[0]:SC0[0]:HE1:SE1] takes: (&inode->inotify_mutex){+.+.?.}, at: [<ffffffff8112f1b5>] inotify_inode_is_dead+0x35/0xb0 {RECLAIM_FS-ON-W} state was registered at: [<ffffffff81079188>] mark_held_locks+0x68/0x90 [<ffffffff810792a5>] lockdep_trace_alloc+0xf5/0x100 [<ffffffff810f5261>] __kmalloc_node+0x31/0x1e0 [<ffffffff81130652>] kernel_event+0xe2/0x190 [<ffffffff81130826>] inotify_dev_queue_event+0x126/0x230 [<ffffffff8112f096>] inotify_inode_queue_event+0xc6/0x110 [<ffffffff8110444d>] vfs_create+0xcd/0x140 [<ffffffff8110825d>] do_filp_open+0x88d/0xa20 [<ffffffff810f6b68>] do_sys_open+0x98/0x140 [<ffffffff810f6c50>] sys_open+0x20/0x30 [<ffffffff8100c272>] system_call_fastpath+0x16/0x1b [<ffffffffffffffff>] 0xffffffffffffffff irq event stamp: 690455 hardirqs last enabled at (690455): [<ffffffff81564fe4>] _spin_unlock_irqrestore+0x44/0x80 hardirqs last disabled at (690454): [<ffffffff81565372>] _spin_lock_irqsave+0x32/0xa0 softirqs last enabled at (690178): [<ffffffff81052282>] __do_softirq+0x202/0x220 softirqs last disabled at (690157): [<ffffffff8100d50c>] call_softirq+0x1c/0x50 other info that might help us debug this: 2 locks held by kswapd0/380: #0: (shrinker_rwsem){++++..}, at: [<ffffffff810d0bd7>] shrink_slab+0x37/0x180 #1: (&type->s_umount_key#17){++++..}, at: [<ffffffff8110cfbf>] shrink_dcache_memory+0x11f/0x1e0 stack backtrace: Pid: 380, comm: kswapd0 Not tainted 2.6.30-rc2-next-20090417 #203 Call Trace: [<ffffffff810789ef>] print_usage_bug+0x19f/0x200 [<ffffffff81018bff>] ? save_stack_trace+0x2f/0x50 [<ffffffff81078f0b>] mark_lock+0x4bb/0x6d0 [<ffffffff810799e0>] ? check_usage_forwards+0x0/0xc0 [<ffffffff8107b142>] __lock_acquire+0xc62/0x1ae0 [<ffffffff810f478c>] ? slob_free+0x10c/0x370 [<ffffffff8107c0a1>] lock_acquire+0xe1/0x120 [<ffffffff8112f1b5>] ? inotify_inode_is_dead+0x35/0xb0 [<ffffffff81562d43>] mutex_lock_nested+0x63/0x420 [<ffffffff8112f1b5>] ? inotify_inode_is_dead+0x35/0xb0 [<ffffffff8112f1b5>] ? inotify_inode_is_dead+0x35/0xb0 [<ffffffff81012fe9>] ? sched_clock+0x9/0x10 [<ffffffff81077165>] ? lock_release_holdtime+0x35/0x1c0 [<ffffffff8112f1b5>] inotify_inode_is_dead+0x35/0xb0 [<ffffffff8110c9dc>] dentry_iput+0xbc/0xe0 [<ffffffff8110cb23>] d_kill+0x33/0x60 [<ffffffff8110ce23>] __shrink_dcache_sb+0x2d3/0x350 [<ffffffff8110cffa>] shrink_dcache_memory+0x15a/0x1e0 [<ffffffff810d0cc5>] shrink_slab+0x125/0x180 [<ffffffff810d1540>] kswapd+0x560/0x7a0 [<ffffffff810ce160>] ? isolate_pages_global+0x0/0x2c0 [<ffffffff81065a30>] ? autoremove_wake_function+0x0/0x40 [<ffffffff8107953d>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff810d0fe0>] ? kswapd+0x0/0x7a0 [<ffffffff8106555b>] kthread+0x5b/0xa0 [<ffffffff8100d40a>] child_rip+0xa/0x20 [<ffffffff8100cdd0>] ? restore_args+0x0/0x30 [<ffffffff81065500>] ? kthread+0x0/0xa0 [<ffffffff8100d400>] ? child_rip+0x0/0x20 [eparis@redhat.com: fix audit too] Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Matt Mackall <mpm@selenic.com> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Eric Paris <eparis@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-27fs: avoid I_NEW inodesNick Piggin
To be on the safe side, it should be less fragile to exclude I_NEW inodes from inode list scans by default (unless there is an important reason to have them). Normally they will get excluded (eg. by zero refcount or writecount etc), however it is a bit fragile for list walkers to know exactly what parts of the inode state is set up and valid to test when in I_NEW. So along these lines, move I_NEW checks upward as well (sometimes taking I_FREEING etc checks with them too -- this shouldn't be a problem should it?) Signed-off-by: Nick Piggin <npiggin@suse.de> Acked-by: Jan Kara <jack@suse.cz> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-02-18inotify: fix GFP_KERNEL related deadlockIngo Molnar
Enhanced lockdep coverage of __GFP_NOFS turned up this new lockdep assert: [ 1093.677775] [ 1093.677781] ================================= [ 1093.680031] [ INFO: inconsistent lock state ] [ 1093.680031] 2.6.29-rc5-tip-01504-gb49eca1-dirty #1 [ 1093.680031] --------------------------------- [ 1093.680031] inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage. [ 1093.680031] kswapd0/308 [HC0[0]:SC0[0]:HE1:SE1] takes: [ 1093.680031] (&inode->inotify_mutex){+.+.?.}, at: [<c0205942>] inotify_inode_is_dead+0x20/0x80 [ 1093.680031] {RECLAIM_FS-ON-W} state was registered at: [ 1093.680031] [<c01696b9>] mark_held_locks+0x43/0x5b [ 1093.680031] [<c016baa4>] lockdep_trace_alloc+0x6c/0x6e [ 1093.680031] [<c01cf8b0>] kmem_cache_alloc+0x20/0x150 [ 1093.680031] [<c040d0ec>] idr_pre_get+0x27/0x6c [ 1093.680031] [<c02056e3>] inotify_handle_get_wd+0x25/0xad [ 1093.680031] [<c0205f43>] inotify_add_watch+0x7a/0x129 [ 1093.680031] [<c020679e>] sys_inotify_add_watch+0x20f/0x250 [ 1093.680031] [<c010389e>] sysenter_do_call+0x12/0x35 [ 1093.680031] [<ffffffff>] 0xffffffff [ 1093.680031] irq event stamp: 60417 [ 1093.680031] hardirqs last enabled at (60417): [<c018d5f5>] call_rcu+0x53/0x59 [ 1093.680031] hardirqs last disabled at (60416): [<c018d5b9>] call_rcu+0x17/0x59 [ 1093.680031] softirqs last enabled at (59656): [<c0146229>] __do_softirq+0x157/0x16b [ 1093.680031] softirqs last disabled at (59651): [<c0106293>] do_softirq+0x74/0x15d [ 1093.680031] [ 1093.680031] other info that might help us debug this: [ 1093.680031] 2 locks held by kswapd0/308: [ 1093.680031] #0: (shrinker_rwsem){++++..}, at: [<c01b0502>] shrink_slab+0x36/0x189 [ 1093.680031] #1: (&type->s_umount_key#4){+++++.}, at: [<c01e6d77>] shrink_dcache_memory+0x110/0x1fb [ 1093.680031] [ 1093.680031] stack backtrace: [ 1093.680031] Pid: 308, comm: kswapd0 Not tainted 2.6.29-rc5-tip-01504-gb49eca1-dirty #1 [ 1093.680031] Call Trace: [ 1093.680031] [<c016947a>] valid_state+0x12a/0x13d [ 1093.680031] [<c016954e>] mark_lock+0xc1/0x1e9 [ 1093.680031] [<c016a5b4>] ? check_usage_forwards+0x0/0x3f [ 1093.680031] [<c016ab74>] __lock_acquire+0x2c6/0xac8 [ 1093.680031] [<c01688d9>] ? register_lock_class+0x17/0x228 [ 1093.680031] [<c016b3d3>] lock_acquire+0x5d/0x7a [ 1093.680031] [<c0205942>] ? inotify_inode_is_dead+0x20/0x80 [ 1093.680031] [<c08824c4>] __mutex_lock_common+0x3a/0x4cb [ 1093.680031] [<c0205942>] ? inotify_inode_is_dead+0x20/0x80 [ 1093.680031] [<c08829ed>] mutex_lock_nested+0x2e/0x36 [ 1093.680031] [<c0205942>] ? inotify_inode_is_dead+0x20/0x80 [ 1093.680031] [<c0205942>] inotify_inode_is_dead+0x20/0x80 [ 1093.680031] [<c01e6672>] dentry_iput+0x90/0xc2 [ 1093.680031] [<c01e67a3>] d_kill+0x21/0x45 [ 1093.680031] [<c01e6a46>] __shrink_dcache_sb+0x27f/0x355 [ 1093.680031] [<c01e6dc5>] shrink_dcache_memory+0x15e/0x1fb [ 1093.680031] [<c01b05ed>] shrink_slab+0x121/0x189 [ 1093.680031] [<c01b0d12>] kswapd+0x39f/0x561 [ 1093.680031] [<c01ae499>] ? isolate_pages_global+0x0/0x233 [ 1093.680031] [<c0157eae>] ? autoremove_wake_function+0x0/0x43 [ 1093.680031] [<c01b0973>] ? kswapd+0x0/0x561 [ 1093.680031] [<c0157daf>] kthread+0x41/0x82 [ 1093.680031] [<c0157d6e>] ? kthread+0x0/0x82 [ 1093.680031] [<c01043ab>] kernel_thread_helper+0x7/0x10 inotify_handle_get_wd() does idr_pre_get() which does a kmem_cache_alloc() without __GFP_FS - and is hence deadlockable under extreme MM pressure. Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: MinChan Kim <minchan.kim@gmail.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-26inotify: clean up inotify_read and fix locking problemsVegard Nossum
If userspace supplies an invalid pointer to a read() of an inotify instance, the inotify device's event list mutex is unlocked twice. This causes an unbalance which effectively leaves the data structure unprotected, and we can trigger oopses by accessing the inotify instance from different tasks concurrently. The best fix (contributed largely by Linus) is a total rewrite of the function in question: On Thu, Jan 22, 2009 at 7:05 AM, Linus Torvalds wrote: > The thing to notice is that: > > - locking is done in just one place, and there is no question about it > not having an unlock. > > - that whole double-while(1)-loop thing is gone. > > - use multiple functions to make nesting and error handling sane > > - do error testing after doing the things you always need to do, ie do > this: > > mutex_lock(..) > ret = function_call(); > mutex_unlock(..) > > .. test ret here .. > > instead of doing conditional exits with unlocking or freeing. > > So if the code is written in this way, it may still be buggy, but at least > it's not buggy because of subtle "forgot to unlock" or "forgot to free" > issues. > > This _always_ unlocks if it locked, and it always frees if it got a > non-error kevent. Cc: John McCutchan <ttb@tentacle.dhs.org> Cc: Robert Love <rlove@google.com> Cc: <stable@kernel.org> Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-14[CVE-2009-0029] System call wrappers part 29Heiko Carstens
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14[CVE-2009-0029] System call wrappers part 28Heiko Carstens
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-05inotify: fix type errors in interfacesMichael Kerrisk
The problems lie in the types used for some inotify interfaces, both at the kernel level and at the glibc level. This mail addresses the kernel problem. I will follow up with some suggestions for glibc changes. For the sys_inotify_rm_watch() interface, the type of the 'wd' argument is currently 'u32', it should be '__s32' . That is Robert's suggestion, and is consistent with the other declarations of watch descriptors in the kernel source, in particular, the inotify_event structure in include/linux/inotify.h: struct inotify_event { __s32 wd; /* watch descriptor */ __u32 mask; /* watch mask */ __u32 cookie; /* cookie to synchronize two events */ __u32 len; /* length (including nulls) of name */ char name[0]; /* stub for possible name */ }; The patch makes the changes needed for inotify_rm_watch(). Signed-off-by: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: Robert Love <rlove@google.com> Cc: Vegard Nossum <vegard.nossum@gmail.com> Cc: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-12-31filesystem notification: create fs/notify to contain all fs notificationEric Paris
Creating a generic filesystem notification interface, fsnotify, which will be used by inotify, dnotify, and eventually fanotify is really starting to clutter the fs directory. This patch simply moves inotify and dnotify into fs/notify/inotify and fs/notify/dnotify respectively to make both current fs/ and future notification tidier. Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>