* [PATCH] Fix inconsistent lock state in inotify
@ 2009-04-10 19:25 Luca Tettamanti
2009-04-14 23:13 ` Andrew Morton
0 siblings, 1 reply; 6+ messages in thread
From: Luca Tettamanti @ 2009-04-10 19:25 UTC (permalink / raw)
To: linux-kernel; +Cc: John McCutchan, Robert Love
Hello,
in current -git lockdep generates the following warning:
=================================
[ INFO: inconsistent lock state ]
2.6.30-rc1-kgdb #182
---------------------------------
inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.
kswapd0/419 [HC0[0]:SC0[0]:HE1:SE1] takes:
(&inode->inotify_mutex){+.+.?.}, at: [<ffffffff802c7036>] inotify_inode_is_dead+0x30/0x94
{RECLAIM_FS-ON-W} state was registered at:
[<ffffffff80259621>] mark_held_locks+0x4d/0x6b
[<ffffffff802596e3>] lockdep_trace_alloc+0xa4/0xbd
[<ffffffff8029ac2e>] __kmalloc+0x51/0xe6
[<ffffffff802c7ea2>] kernel_event+0xa7/0x10e
[<ffffffff802c7fdc>] inotify_dev_queue_event+0xd3/0x14b
[<ffffffff802c6f56>] inotify_inode_queue_event+0xab/0xe0
[<ffffffff802a6d83>] vfs_create+0xb1/0xc0
[<ffffffff802a975a>] do_filp_open+0x240/0x842
[<ffffffff8029cb1e>] do_sys_open+0x53/0xda
[<ffffffff802d0a62>] compat_sys_open+0x15/0x17
[<ffffffff80228e14>] sysenter_dispatch+0x7/0x30
[<ffffffffffffffff>] 0xffffffffffffffff
irq event stamp: 30075
hardirqs last enabled at (30075): [<ffffffff802712cf>] call_rcu+0x5d/0x6a
hardirqs last disabled at (30074): [<ffffffff80271296>] call_rcu+0x24/0x6a
softirqs last enabled at (27584): [<ffffffff8023d151>] __do_softirq+0x115/0x124
softirqs last disabled at (27573): [<ffffffff8020c13c>] call_softirq+0x1c/0x28
other info that might help us debug this:
2 locks held by kswapd0/419:
#0: (shrinker_rwsem){++++..}, at: [<ffffffff8027dd86>] shrink_slab+0x38/0x188
#1: (&type->s_umount_key#16){++++..}, at: [<ffffffff802ad8c9>] shrink_dcache_memory+0xb9/0x193
stack backtrace:
Pid: 419, comm: kswapd0 Not tainted 2.6.30-rc1-kgdb #182
Call Trace:
[<ffffffff8025906c>] print_usage_bug+0x1b6/0x1c7
[<ffffffff80259c54>] ? check_usage_forwards+0x0/0xa1
[<ffffffff8025938f>] mark_lock+0x312/0x557
[<ffffffff8025ad03>] __lock_acquire+0x7b7/0x1668
[<ffffffff802c7036>] ? inotify_inode_is_dead+0x30/0x94
[<ffffffff8025bc09>] lock_acquire+0x55/0x71
[<ffffffff802c7036>] ? inotify_inode_is_dead+0x30/0x94
[<ffffffff80442ec8>] mutex_lock_nested+0x5a/0x2fa
[<ffffffff802c7036>] ? inotify_inode_is_dead+0x30/0x94
[<ffffffff80259621>] ? mark_held_locks+0x4d/0x6b
[<ffffffff802712cf>] ? call_rcu+0x5d/0x6a
[<ffffffff802c7036>] inotify_inode_is_dead+0x30/0x94
[<ffffffff802ad3f1>] dentry_iput+0x82/0xc1
[<ffffffff802ad4f9>] d_kill+0x24/0x45
[<ffffffff802ad778>] __shrink_dcache_sb+0x25e/0x2f6
[<ffffffff802ad901>] shrink_dcache_memory+0xf1/0x193
[<ffffffff8027de2d>] shrink_slab+0xdf/0x188
[<ffffffff8027e3be>] kswapd+0x4e8/0x6a3
[<ffffffff80232d0c>] ? finish_task_switch+0x3b/0x10c
[<ffffffff8027bec4>] ? isolate_pages_global+0x0/0x26f
[<ffffffff8024becf>] ? autoremove_wake_function+0x0/0x38
[<ffffffff802598d6>] ? trace_hardirqs_on+0xd/0xf
[<ffffffff80444a41>] ? _spin_unlock_irqrestore+0x4c/0x68
[<ffffffff8027ded6>] ? kswapd+0x0/0x6a3
[<ffffffff8027ded6>] ? kswapd+0x0/0x6a3
[<ffffffff8024bb80>] kthread+0x49/0x76
[<ffffffff8020c03a>] child_rip+0xa/0x20
[<ffffffff8020ba00>] ? restore_args+0x0/0x30
[<ffffffff8024bb37>] ? kthread+0x0/0x76
[<ffffffff8020c030>] ? child_rip+0x0/0x20
The cause is a call to kmalloc with GFP_KERNEL; the following patch
changes the flag to GFP_NOFS, which is also consistent with an earlier
call to kmem_cache_alloc in the same function.
Signed-off-by: Luca Tettamanti <kronos.it@gmail.com>
---
fs/notify/inotify/inotify_user.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index bed766e..1634319 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -220,7 +220,7 @@ static struct inotify_kernel_event * kernel_event(s32 wd, u32 mask, u32 cookie,
rem = 0;
}
- kevent->name = kmalloc(len + rem, GFP_KERNEL);
+ kevent->name = kmalloc(len + rem, GFP_NOFS);
if (unlikely(!kevent->name)) {
kmem_cache_free(event_cachep, kevent);
return NULL;
Luca
--
"La teoria e` quando sappiamo come funzionano le cose ma non funzionano.
La pratica e` quando le cose funzionano ma non sappiamo perche`.
Abbiamo unito la teoria e la pratica: le cose non funzionano piu` e non
sappiamo il perche`." -- A. Einstein
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] Fix inconsistent lock state in inotify
2009-04-10 19:25 [PATCH] Fix inconsistent lock state in inotify Luca Tettamanti
@ 2009-04-14 23:13 ` Andrew Morton
2009-04-15 11:59 ` Luca Tettamanti
0 siblings, 1 reply; 6+ messages in thread
From: Andrew Morton @ 2009-04-14 23:13 UTC (permalink / raw)
To: Luca Tettamanti; +Cc: linux-kernel, john, rlove, Eric Paris
On Fri, 10 Apr 2009 21:25:33 +0200
Luca Tettamanti <kronos.it@gmail.com> wrote:
> Hello,
> in current -git lockdep generates the following warning:
>
> =================================
> [ INFO: inconsistent lock state ]
> 2.6.30-rc1-kgdb #182
> ---------------------------------
> inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.
> kswapd0/419 [HC0[0]:SC0[0]:HE1:SE1] takes:
> (&inode->inotify_mutex){+.+.?.}, at: [<ffffffff802c7036>] inotify_inode_is_dead+0x30/0x94
> {RECLAIM_FS-ON-W} state was registered at:
> [<ffffffff80259621>] mark_held_locks+0x4d/0x6b
> [<ffffffff802596e3>] lockdep_trace_alloc+0xa4/0xbd
> [<ffffffff8029ac2e>] __kmalloc+0x51/0xe6
> [<ffffffff802c7ea2>] kernel_event+0xa7/0x10e
> [<ffffffff802c7fdc>] inotify_dev_queue_event+0xd3/0x14b
> [<ffffffff802c6f56>] inotify_inode_queue_event+0xab/0xe0
> [<ffffffff802a6d83>] vfs_create+0xb1/0xc0
> [<ffffffff802a975a>] do_filp_open+0x240/0x842
> [<ffffffff8029cb1e>] do_sys_open+0x53/0xda
> [<ffffffff802d0a62>] compat_sys_open+0x15/0x17
> [<ffffffff80228e14>] sysenter_dispatch+0x7/0x30
> [<ffffffffffffffff>] 0xffffffffffffffff
> irq event stamp: 30075
> hardirqs last enabled at (30075): [<ffffffff802712cf>] call_rcu+0x5d/0x6a
> hardirqs last disabled at (30074): [<ffffffff80271296>] call_rcu+0x24/0x6a
> softirqs last enabled at (27584): [<ffffffff8023d151>] __do_softirq+0x115/0x124
> softirqs last disabled at (27573): [<ffffffff8020c13c>] call_softirq+0x1c/0x28
>
> other info that might help us debug this:
> 2 locks held by kswapd0/419:
> #0: (shrinker_rwsem){++++..}, at: [<ffffffff8027dd86>] shrink_slab+0x38/0x188
> #1: (&type->s_umount_key#16){++++..}, at: [<ffffffff802ad8c9>] shrink_dcache_memory+0xb9/0x193
>
> stack backtrace:
> Pid: 419, comm: kswapd0 Not tainted 2.6.30-rc1-kgdb #182
> Call Trace:
> [<ffffffff8025906c>] print_usage_bug+0x1b6/0x1c7
> [<ffffffff80259c54>] ? check_usage_forwards+0x0/0xa1
> [<ffffffff8025938f>] mark_lock+0x312/0x557
> [<ffffffff8025ad03>] __lock_acquire+0x7b7/0x1668
> [<ffffffff802c7036>] ? inotify_inode_is_dead+0x30/0x94
> [<ffffffff8025bc09>] lock_acquire+0x55/0x71
> [<ffffffff802c7036>] ? inotify_inode_is_dead+0x30/0x94
> [<ffffffff80442ec8>] mutex_lock_nested+0x5a/0x2fa
> [<ffffffff802c7036>] ? inotify_inode_is_dead+0x30/0x94
> [<ffffffff80259621>] ? mark_held_locks+0x4d/0x6b
> [<ffffffff802712cf>] ? call_rcu+0x5d/0x6a
> [<ffffffff802c7036>] inotify_inode_is_dead+0x30/0x94
> [<ffffffff802ad3f1>] dentry_iput+0x82/0xc1
> [<ffffffff802ad4f9>] d_kill+0x24/0x45
> [<ffffffff802ad778>] __shrink_dcache_sb+0x25e/0x2f6
> [<ffffffff802ad901>] shrink_dcache_memory+0xf1/0x193
> [<ffffffff8027de2d>] shrink_slab+0xdf/0x188
> [<ffffffff8027e3be>] kswapd+0x4e8/0x6a3
> [<ffffffff80232d0c>] ? finish_task_switch+0x3b/0x10c
> [<ffffffff8027bec4>] ? isolate_pages_global+0x0/0x26f
> [<ffffffff8024becf>] ? autoremove_wake_function+0x0/0x38
> [<ffffffff802598d6>] ? trace_hardirqs_on+0xd/0xf
> [<ffffffff80444a41>] ? _spin_unlock_irqrestore+0x4c/0x68
> [<ffffffff8027ded6>] ? kswapd+0x0/0x6a3
> [<ffffffff8027ded6>] ? kswapd+0x0/0x6a3
> [<ffffffff8024bb80>] kthread+0x49/0x76
> [<ffffffff8020c03a>] child_rip+0xa/0x20
> [<ffffffff8020ba00>] ? restore_args+0x0/0x30
> [<ffffffff8024bb37>] ? kthread+0x0/0x76
> [<ffffffff8020c030>] ? child_rip+0x0/0x20
>
> The cause is a call to kmalloc with GFP_KERNEL; the following patch
> changes the flag to GFP_NOFS, which is also consistent with an earlier
> call to kmem_cache_alloc in the same function.
>
> Signed-off-by: Luca Tettamanti <kronos.it@gmail.com>
> ---
>
> fs/notify/inotify/inotify_user.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
> index bed766e..1634319 100644
> --- a/fs/notify/inotify/inotify_user.c
> +++ b/fs/notify/inotify/inotify_user.c
> @@ -220,7 +220,7 @@ static struct inotify_kernel_event * kernel_event(s32 wd, u32 mask, u32 cookie,
> rem = 0;
> }
>
> - kevent->name = kmalloc(len + rem, GFP_KERNEL);
> + kevent->name = kmalloc(len + rem, GFP_NOFS);
> if (unlikely(!kevent->name)) {
> kmem_cache_free(event_cachep, kevent);
> return NULL;
Thanks.
This is in fact a false positive and we plan to fix it via lockdep
annotation.
(where "we" == eparis@redhat.com ;))
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] Fix inconsistent lock state in inotify
2009-04-14 23:13 ` Andrew Morton
@ 2009-04-15 11:59 ` Luca Tettamanti
2009-04-15 19:25 ` Andrew Morton
0 siblings, 1 reply; 6+ messages in thread
From: Luca Tettamanti @ 2009-04-15 11:59 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-kernel, john, rlove, Eric Paris
On Wed, Apr 15, 2009 at 1:13 AM, Andrew Morton
<akpm@linux-foundation.org> wrote:
> On Fri, 10 Apr 2009 21:25:33 +0200
> Luca Tettamanti <kronos.it@gmail.com> wrote:
>
>> Hello,
>> in current -git lockdep generates the following warning:
>>
>> =================================
>> [ INFO: inconsistent lock state ]
>> 2.6.30-rc1-kgdb #182
>> ---------------------------------
>> inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.
>> kswapd0/419 [HC0[0]:SC0[0]:HE1:SE1] takes:
>> (&inode->inotify_mutex){+.+.?.}, at: [<ffffffff802c7036>] inotify_inode_is_dead+0x30/0x94
>> {RECLAIM_FS-ON-W} state was registered at:
>> [<ffffffff80259621>] mark_held_locks+0x4d/0x6b
>> [<ffffffff802596e3>] lockdep_trace_alloc+0xa4/0xbd
>> [<ffffffff8029ac2e>] __kmalloc+0x51/0xe6
>> [<ffffffff802c7ea2>] kernel_event+0xa7/0x10e
>> [<ffffffff802c7fdc>] inotify_dev_queue_event+0xd3/0x14b
>> [<ffffffff802c6f56>] inotify_inode_queue_event+0xab/0xe0
>> [<ffffffff802a6d83>] vfs_create+0xb1/0xc0
>> [<ffffffff802a975a>] do_filp_open+0x240/0x842
>> [<ffffffff8029cb1e>] do_sys_open+0x53/0xda
>> [<ffffffff802d0a62>] compat_sys_open+0x15/0x17
>> [<ffffffff80228e14>] sysenter_dispatch+0x7/0x30
>> [<ffffffffffffffff>] 0xffffffffffffffff
>> irq event stamp: 30075
>> hardirqs last enabled at (30075): [<ffffffff802712cf>] call_rcu+0x5d/0x6a
>> hardirqs last disabled at (30074): [<ffffffff80271296>] call_rcu+0x24/0x6a
>> softirqs last enabled at (27584): [<ffffffff8023d151>] __do_softirq+0x115/0x124
>> softirqs last disabled at (27573): [<ffffffff8020c13c>] call_softirq+0x1c/0x28
>>
>> other info that might help us debug this:
>> 2 locks held by kswapd0/419:
>> #0: (shrinker_rwsem){++++..}, at: [<ffffffff8027dd86>] shrink_slab+0x38/0x188
>> #1: (&type->s_umount_key#16){++++..}, at: [<ffffffff802ad8c9>] shrink_dcache_memory+0xb9/0x193
>>
>> stack backtrace:
>> Pid: 419, comm: kswapd0 Not tainted 2.6.30-rc1-kgdb #182
>> Call Trace:
>> [<ffffffff8025906c>] print_usage_bug+0x1b6/0x1c7
>> [<ffffffff80259c54>] ? check_usage_forwards+0x0/0xa1
>> [<ffffffff8025938f>] mark_lock+0x312/0x557
>> [<ffffffff8025ad03>] __lock_acquire+0x7b7/0x1668
>> [<ffffffff802c7036>] ? inotify_inode_is_dead+0x30/0x94
>> [<ffffffff8025bc09>] lock_acquire+0x55/0x71
>> [<ffffffff802c7036>] ? inotify_inode_is_dead+0x30/0x94
>> [<ffffffff80442ec8>] mutex_lock_nested+0x5a/0x2fa
>> [<ffffffff802c7036>] ? inotify_inode_is_dead+0x30/0x94
>> [<ffffffff80259621>] ? mark_held_locks+0x4d/0x6b
>> [<ffffffff802712cf>] ? call_rcu+0x5d/0x6a
>> [<ffffffff802c7036>] inotify_inode_is_dead+0x30/0x94
>> [<ffffffff802ad3f1>] dentry_iput+0x82/0xc1
>> [<ffffffff802ad4f9>] d_kill+0x24/0x45
>> [<ffffffff802ad778>] __shrink_dcache_sb+0x25e/0x2f6
>> [<ffffffff802ad901>] shrink_dcache_memory+0xf1/0x193
>> [<ffffffff8027de2d>] shrink_slab+0xdf/0x188
>> [<ffffffff8027e3be>] kswapd+0x4e8/0x6a3
>> [<ffffffff80232d0c>] ? finish_task_switch+0x3b/0x10c
>> [<ffffffff8027bec4>] ? isolate_pages_global+0x0/0x26f
>> [<ffffffff8024becf>] ? autoremove_wake_function+0x0/0x38
>> [<ffffffff802598d6>] ? trace_hardirqs_on+0xd/0xf
>> [<ffffffff80444a41>] ? _spin_unlock_irqrestore+0x4c/0x68
>> [<ffffffff8027ded6>] ? kswapd+0x0/0x6a3
>> [<ffffffff8027ded6>] ? kswapd+0x0/0x6a3
>> [<ffffffff8024bb80>] kthread+0x49/0x76
>> [<ffffffff8020c03a>] child_rip+0xa/0x20
>> [<ffffffff8020ba00>] ? restore_args+0x0/0x30
>> [<ffffffff8024bb37>] ? kthread+0x0/0x76
>> [<ffffffff8020c030>] ? child_rip+0x0/0x20
>>
>> The cause is a call to kmalloc with GFP_KERNEL; the following patch
>> changes the flag to GFP_NOFS, which is also consistent with an earlier
>> call to kmem_cache_alloc in the same function.
>>
>> Signed-off-by: Luca Tettamanti <kronos.it@gmail.com>
>> ---
>>
>> fs/notify/inotify/inotify_user.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
>> index bed766e..1634319 100644
>> --- a/fs/notify/inotify/inotify_user.c
>> +++ b/fs/notify/inotify/inotify_user.c
>> @@ -220,7 +220,7 @@ static struct inotify_kernel_event * kernel_event(s32 wd, u32 mask, u32 cookie,
>> rem = 0;
>> }
>>
>> - kevent->name = kmalloc(len + rem, GFP_KERNEL);
>> + kevent->name = kmalloc(len + rem, GFP_NOFS);
>> if (unlikely(!kevent->name)) {
>> kmem_cache_free(event_cachep, kevent);
>> return NULL;
>
> Thanks.
>
> This is in fact a false positive and we plan to fix it via lockdep
> annotation.
Well, I trust you on the "false positive", but a few line before there this:
kevent = kmem_cache_alloc(event_cachep, GFP_NOFS);
so can kmem_cache_alloc also use GFP_KERNEL?
Luca
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] Fix inconsistent lock state in inotify
2009-04-15 11:59 ` Luca Tettamanti
@ 2009-04-15 19:25 ` Andrew Morton
2009-04-15 19:31 ` Eric Paris
0 siblings, 1 reply; 6+ messages in thread
From: Andrew Morton @ 2009-04-15 19:25 UTC (permalink / raw)
To: Luca Tettamanti; +Cc: linux-kernel, john, rlove, eparis
On Wed, 15 Apr 2009 13:59:29 +0200
Luca Tettamanti <kronos.it@gmail.com> wrote:
> >> +++ b/fs/notify/inotify/inotify_user.c
> >> @@ -220,7 +220,7 @@ static struct inotify_kernel_event * kernel_event(s32 wd, u32 mask, u32 cookie,
> >> rem = 0;
> >> }
> >>
> >> - kevent->name = kmalloc(len + rem, GFP_KERNEL);
> >> + kevent->name = kmalloc(len + rem, GFP_NOFS);
> >> if (unlikely(!kevent->name)) {
> >> kmem_cache_free(event_cachep, kevent);
> >> return NULL;
> >
> > Thanks.
> >
> > This is in fact a false positive and we plan to fix it via lockdep
> > annotation.
>
> Well, I trust you on the "false positive", but a few line before there this:
>
> kevent = kmem_cache_alloc(event_cachep, GFP_NOFS);
>
> so can kmem_cache_alloc also use GFP_KERNEL?
Yes, it looks that way.
umm, I think I'll merge your original patch as a reminder-to-self.
If the problem doesn't get fixed in a better way for 2.6.30 then I
might end up going with the GFP_NOFS approach.
But it's bad to weaken the memory allocation mode just to plug a lockdep
warning.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] Fix inconsistent lock state in inotify
2009-04-15 19:25 ` Andrew Morton
@ 2009-04-15 19:31 ` Eric Paris
2009-04-15 20:31 ` Andrew Morton
0 siblings, 1 reply; 6+ messages in thread
From: Eric Paris @ 2009-04-15 19:31 UTC (permalink / raw)
To: Andrew Morton; +Cc: Luca Tettamanti, linux-kernel, john, rlove
On Wed, 2009-04-15 at 12:25 -0700, Andrew Morton wrote:
> On Wed, 15 Apr 2009 13:59:29 +0200
> Luca Tettamanti <kronos.it@gmail.com> wrote:
>
> > >> +++ b/fs/notify/inotify/inotify_user.c
> > >> @@ -220,7 +220,7 @@ static struct inotify_kernel_event * kernel_event(s32 wd, u32 mask, u32 cookie,
> > >> rem = 0;
> > >> }
> > >>
> > >> - kevent->name = kmalloc(len + rem, GFP_KERNEL);
> > >> + kevent->name = kmalloc(len + rem, GFP_NOFS);
> > >> if (unlikely(!kevent->name)) {
> > >> kmem_cache_free(event_cachep, kevent);
> > >> return NULL;
> > >
> > > Thanks.
> > >
> > > This is in fact a false positive and we plan to fix it via lockdep
> > > annotation.
> >
> > Well, I trust you on the "false positive", but a few line before there this:
> >
> > kevent = kmem_cache_alloc(event_cachep, GFP_NOFS);
> >
> > so can kmem_cache_alloc also use GFP_KERNEL?
>
> Yes, it looks that way.
>
> umm, I think I'll merge your original patch as a reminder-to-self.
> If the problem doesn't get fixed in a better way for 2.6.30 then I
> might end up going with the GFP_NOFS approach.
>
> But it's bad to weaken the memory allocation mode just to plug a lockdep
> warning.
I swear, I'm fighting with my machines trying to get one to work so I
can test my lockdep fix today (and found a separate oddity/bug in the
process)
-Eric
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] Fix inconsistent lock state in inotify
2009-04-15 19:31 ` Eric Paris
@ 2009-04-15 20:31 ` Andrew Morton
0 siblings, 0 replies; 6+ messages in thread
From: Andrew Morton @ 2009-04-15 20:31 UTC (permalink / raw)
To: Eric Paris; +Cc: kronos.it, linux-kernel, john, rlove
On Wed, 15 Apr 2009 15:31:35 -0400
Eric Paris <eparis@redhat.com> wrote:
> On Wed, 2009-04-15 at 12:25 -0700, Andrew Morton wrote:
> > On Wed, 15 Apr 2009 13:59:29 +0200
> > Luca Tettamanti <kronos.it@gmail.com> wrote:
> >
> > > >> +++ b/fs/notify/inotify/inotify_user.c
> > > >> @@ -220,7 +220,7 @@ static struct inotify_kernel_event * kernel_event(s32 wd, u32 mask, u32 cookie,
> > > >> rem = 0;
> > > >> }
> > > >>
> > > >> - kevent->name = kmalloc(len + rem, GFP_KERNEL);
> > > >> + kevent->name = kmalloc(len + rem, GFP_NOFS);
> > > >> if (unlikely(!kevent->name)) {
> > > >> kmem_cache_free(event_cachep, kevent);
> > > >> return NULL;
> > > >
> > > > Thanks.
> > > >
> > > > This is in fact a false positive and we plan to fix it via lockdep
> > > > annotation.
> > >
> > > Well, I trust you on the "false positive", but a few line before there this:
> > >
> > > kevent = kmem_cache_alloc(event_cachep, GFP_NOFS);
> > >
> > > so can kmem_cache_alloc also use GFP_KERNEL?
> >
> > Yes, it looks that way.
> >
> > umm, I think I'll merge your original patch as a reminder-to-self.
> > If the problem doesn't get fixed in a better way for 2.6.30 then I
> > might end up going with the GFP_NOFS approach.
> >
> > But it's bad to weaken the memory allocation mode just to plug a lockdep
> > warning.
>
> I swear, I'm fighting with my machines trying to get one to work so I
> can test my lockdep fix today (and found a separate oddity/bug in the
> process)
>
heh, thanks. No rush, it's a tiny problem. Some time this week or
next would be OK.
I get all paranoid about things falling through cracks.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2009-04-15 20:34 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2009-04-10 19:25 [PATCH] Fix inconsistent lock state in inotify Luca Tettamanti
2009-04-14 23:13 ` Andrew Morton
2009-04-15 11:59 ` Luca Tettamanti
2009-04-15 19:25 ` Andrew Morton
2009-04-15 19:31 ` Eric Paris
2009-04-15 20:31 ` Andrew Morton
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