Hi, Ingo and Peter. FYI, Before, I reported this problem. http://lkml.org/lkml/2009/2/2/415 But, fs-guy didn't have any response. Let's retry. On Mon, Feb 16, 2009 at 7:34 PM, Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote: > On Mon, 2009-02-16 at 09:13 +0100, Ingo Molnar wrote: > >> From 3023a3e27b909b3b309edac4bc9beb8103f127fa Mon Sep 17 00:00:00 2001 >> From: Ingo Molnar <mingo@xxxxxxx> >> Date: Mon, 16 Feb 2009 09:10:32 +0100 >> Subject: [PATCH] inotify: fix GFP_KERNEL related deadlock >> >> 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@xxxxxxx> > > Looks like a good catch, > > Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> > >> --- >> fs/notify/inotify/inotify.c | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/fs/notify/inotify/inotify.c b/fs/notify/inotify/inotify.c >> index dae3f28..331f2e8 100644 >> --- a/fs/notify/inotify/inotify.c >> +++ b/fs/notify/inotify/inotify.c >> @@ -156,7 +156,7 @@ static int inotify_handle_get_wd(struct inotify_handle *ih, >> int ret; >> >> do { >> - if (unlikely(!idr_pre_get(&ih->idr, GFP_KERNEL))) >> + if (unlikely(!idr_pre_get(&ih->idr, GFP_NOFS))) >> return -ENOSPC; >> ret = idr_get_new_above(&ih->idr, watch, ih->last_wd+1, &watch->wd); >> } while (ret == -EAGAIN); > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- Kinds regards, MinChan Kim -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
