Hi
I've enabled rcu correctness for my todays 2.6.34-rc2 kernel.
I'm getting this INFO: from my kvm guest (which uses host's nfs
exported directory.)
This
===================================================
[ INFO: suspicious rcu_dereference_check() usage. ]
---------------------------------------------------
fs/nfs/delegation.c:348 invoked rcu_dereference_check() without protection!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 0
2 locks held by rm/1820:
#0: (&sb->s_type->i_mutex_key#13/1){+.+.+.}, at:
[<ffffffff81138e1b>] do_unlinkat+0x9b/0x1c0
#1: (&sb->s_type->i_mutex_key#13){+.+.+.}, at: [<ffffffff81136a76>]
vfs_unlink+0x56/0xf0
stack backtrace:
Pid: 1820, comm: rm Not tainted 2.6.34-rc2-00186-ge79a302 #60
Call Trace:
[<ffffffff810819fb>] lockdep_rcu_dereference+0xbb/0xc0
[<ffffffffa0228351>] nfs_inode_return_delegation+0x101/0x110 [nfs]
[<ffffffffa01fd58d>] nfs_unlink+0xad/0x2a0 [nfs]
[<ffffffff81136aba>] vfs_unlink+0x9a/0xf0
[<ffffffff81148365>] ? mnt_want_write+0x65/0xb0
[<ffffffff81138f03>] do_unlinkat+0x183/0x1c0
[<ffffffff8142b66d>] ? retint_swapgs+0xe/0x13
[<ffffffff81083985>] ? trace_hardirqs_on_caller+0x155/0x1a0
[<ffffffff8142a232>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[<ffffffff811390a2>] sys_unlinkat+0x22/0x40
[<ffffffff81031dc8>] sysenter_dispatch+0x7/0x2c
Zdenek
On Thu, 2010-03-25 at 11:48 +0100, Zdenek Kabelac wrote:
> Hi
>
> I've enabled rcu correctness for my todays 2.6.34-rc2 kernel.
>
> I'm getting this INFO: from my kvm guest (which uses host's nfs
> exported directory.)
> This
>
> ===================================================
> [ INFO: suspicious rcu_dereference_check() usage. ]
> ---------------------------------------------------
> fs/nfs/delegation.c:348 invoked rcu_dereference_check() without protection!
>
> other info that might help us debug this:
>
>
> rcu_scheduler_active = 1, debug_locks = 0
> 2 locks held by rm/1820:
> #0: (&sb->s_type->i_mutex_key#13/1){+.+.+.}, at:
> [<ffffffff81138e1b>] do_unlinkat+0x9b/0x1c0
> #1: (&sb->s_type->i_mutex_key#13){+.+.+.}, at: [<ffffffff81136a76>]
> vfs_unlink+0x56/0xf0
>
> stack backtrace:
> Pid: 1820, comm: rm Not tainted 2.6.34-rc2-00186-ge79a302 #60
> Call Trace:
> [<ffffffff810819fb>] lockdep_rcu_dereference+0xbb/0xc0
> [<ffffffffa0228351>] nfs_inode_return_delegation+0x101/0x110 [nfs]
> [<ffffffffa01fd58d>] nfs_unlink+0xad/0x2a0 [nfs]
> [<ffffffff81136aba>] vfs_unlink+0x9a/0xf0
> [<ffffffff81148365>] ? mnt_want_write+0x65/0xb0
> [<ffffffff81138f03>] do_unlinkat+0x183/0x1c0
> [<ffffffff8142b66d>] ? retint_swapgs+0xe/0x13
> [<ffffffff81083985>] ? trace_hardirqs_on_caller+0x155/0x1a0
> [<ffffffff8142a232>] ? trace_hardirqs_on_thunk+0x3a/0x3f
> [<ffffffff811390a2>] sys_unlinkat+0x22/0x40
> [<ffffffff81031dc8>] sysenter_dispatch+0x7/0x2c
>
It is a 100% bogus warning. There are tentative patches floating around
to fix the above warning, but they haven't been merged yet.
In the meantime, please ignore...
Cheers
Trond
On Thu, Mar 25, 2010 at 11:36:40AM -0400, Trond Myklebust wrote:
> On Thu, 2010-03-25 at 11:48 +0100, Zdenek Kabelac wrote:
> > Hi
> >
> > I've enabled rcu correctness for my todays 2.6.34-rc2 kernel.
> >
> > I'm getting this INFO: from my kvm guest (which uses host's nfs
> > exported directory.)
> > This
> >
> > ===================================================
> > [ INFO: suspicious rcu_dereference_check() usage. ]
> > ---------------------------------------------------
> > fs/nfs/delegation.c:348 invoked rcu_dereference_check() without protection!
> >
> > other info that might help us debug this:
> >
> >
> > rcu_scheduler_active = 1, debug_locks = 0
> > 2 locks held by rm/1820:
> > #0: (&sb->s_type->i_mutex_key#13/1){+.+.+.}, at:
> > [<ffffffff81138e1b>] do_unlinkat+0x9b/0x1c0
> > #1: (&sb->s_type->i_mutex_key#13){+.+.+.}, at: [<ffffffff81136a76>]
> > vfs_unlink+0x56/0xf0
> >
> > stack backtrace:
> > Pid: 1820, comm: rm Not tainted 2.6.34-rc2-00186-ge79a302 #60
> > Call Trace:
> > [<ffffffff810819fb>] lockdep_rcu_dereference+0xbb/0xc0
> > [<ffffffffa0228351>] nfs_inode_return_delegation+0x101/0x110 [nfs]
> > [<ffffffffa01fd58d>] nfs_unlink+0xad/0x2a0 [nfs]
> > [<ffffffff81136aba>] vfs_unlink+0x9a/0xf0
> > [<ffffffff81148365>] ? mnt_want_write+0x65/0xb0
> > [<ffffffff81138f03>] do_unlinkat+0x183/0x1c0
> > [<ffffffff8142b66d>] ? retint_swapgs+0xe/0x13
> > [<ffffffff81083985>] ? trace_hardirqs_on_caller+0x155/0x1a0
> > [<ffffffff8142a232>] ? trace_hardirqs_on_thunk+0x3a/0x3f
> > [<ffffffff811390a2>] sys_unlinkat+0x22/0x40
> > [<ffffffff81031dc8>] sysenter_dispatch+0x7/0x2c
> >
>
> It is a 100% bogus warning. There are tentative patches floating around
> to fix the above warning, but they haven't been merged yet.
>
> In the meantime, please ignore...
Did you want to carry these patches, or would you rather that I do so?
(And sorry for the slow response, was on holiday last week.)
Thanx, Paul
On Mon, 2010-03-29 at 08:25 -0700, Paul E. McKenney wrote:
> On Thu, Mar 25, 2010 at 11:36:40AM -0400, Trond Myklebust wrote:
> > On Thu, 2010-03-25 at 11:48 +0100, Zdenek Kabelac wrote:
> > > Hi
> > >
> > > I've enabled rcu correctness for my todays 2.6.34-rc2 kernel.
> > >
> > > I'm getting this INFO: from my kvm guest (which uses host's nfs
> > > exported directory.)
> > > This
> > >
> > > ===================================================
> > > [ INFO: suspicious rcu_dereference_check() usage. ]
> > > ---------------------------------------------------
> > > fs/nfs/delegation.c:348 invoked rcu_dereference_check() without protection!
> > >
> > > other info that might help us debug this:
> > >
> > >
> > > rcu_scheduler_active = 1, debug_locks = 0
> > > 2 locks held by rm/1820:
> > > #0: (&sb->s_type->i_mutex_key#13/1){+.+.+.}, at:
> > > [<ffffffff81138e1b>] do_unlinkat+0x9b/0x1c0
> > > #1: (&sb->s_type->i_mutex_key#13){+.+.+.}, at: [<ffffffff81136a76>]
> > > vfs_unlink+0x56/0xf0
> > >
> > > stack backtrace:
> > > Pid: 1820, comm: rm Not tainted 2.6.34-rc2-00186-ge79a302 #60
> > > Call Trace:
> > > [<ffffffff810819fb>] lockdep_rcu_dereference+0xbb/0xc0
> > > [<ffffffffa0228351>] nfs_inode_return_delegation+0x101/0x110 [nfs]
> > > [<ffffffffa01fd58d>] nfs_unlink+0xad/0x2a0 [nfs]
> > > [<ffffffff81136aba>] vfs_unlink+0x9a/0xf0
> > > [<ffffffff81148365>] ? mnt_want_write+0x65/0xb0
> > > [<ffffffff81138f03>] do_unlinkat+0x183/0x1c0
> > > [<ffffffff8142b66d>] ? retint_swapgs+0xe/0x13
> > > [<ffffffff81083985>] ? trace_hardirqs_on_caller+0x155/0x1a0
> > > [<ffffffff8142a232>] ? trace_hardirqs_on_thunk+0x3a/0x3f
> > > [<ffffffff811390a2>] sys_unlinkat+0x22/0x40
> > > [<ffffffff81031dc8>] sysenter_dispatch+0x7/0x2c
> > >
> >
> > It is a 100% bogus warning. There are tentative patches floating around
> > to fix the above warning, but they haven't been merged yet.
> >
> > In the meantime, please ignore...
>
> Did you want to carry these patches, or would you rather that I do so?
>
> (And sorry for the slow response, was on holiday last week.)
>
> Thanx, Paul
Hi Paul,
I don't mind whether you or I push them to Linus, but IIRC you had a
couple of comments about the last patchset I saw from David, so I was
expecting to see either a reply from him or patch update. Did I miss
that reply? (Ccing: David)
Cheers
Trond