Re: [PATCHSET v2] sysfs: use seq_file and unify regular and bin filehandling

From: Tejun Heo
Date: Mon Oct 14 2013 - 08:47:22 EST


Hello, guys.

Sorry about the delay.

On Fri, Oct 11, 2013 at 12:11:18PM -0700, Yinghai Lu wrote:
> [ 448.189960] ------------[ cut here ]------------
> [ 448.195214] WARNING: CPU: 6 PID: 69219 at fs/sysfs/file.c:79
> sysfs_file_ops+0x59/0x70()

So, that's "lockdep_assert_held(sd);" in sysfs_file_ops().

> [ 448.273805] [<ffffffff81248bd9>] sysfs_file_ops+0x59/0x70
> [ 448.279973] [<ffffffff81249628>] sysfs_open_file+0x88/0x330

Triggering from sysfs_open_file()

> [ 448.366842] ------------[ cut here ]------------
> [ 448.372030] WARNING: CPU: 6 PID: 69219 at fs/sysfs/file.c:79
> sysfs_file_ops+0x59/0x70()
...
> [ 448.457806] [<ffffffff81248cbb>] sysfs_seq_show+0xcb/0x180

and then from sysfs_seq_show(), which is weird because
lockdep_assert_held(sd) checks whether sd's active ref is held and
both do hold them. Hmm.... ah, right, I forgot about
->ignore_lockdep, we need to skip the assertion for files marked with
ignore_lockdep. Will send a patch soon.

Thanks.

--
tejun
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