Bug 526853

Summary: kernel warning at fs/inotify.c:202/set_dentry_child_flags()
Product: Red Hat Enterprise Linux 5 Reporter: Robin Humble <robin.humble+redhat>
Component: kernelAssignee: Red Hat Kernel Manager <kernel-mgr>
Status: CLOSED DUPLICATE QA Contact: Red Hat Kernel QE team <kernel-qe>
Severity: low Docs Contact:
Priority: low    
Version: 5.4CC: cward, eparis, rhn, robin.humble+redhat
Target Milestone: rc   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
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Clone Of: Environment:
Last Closed: 2009-10-19 14:56:08 UTC Type: ---
Regression: --- Mount Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description Robin Humble 2009-10-02 05:27:46 UTC 
Description of problem:

we see these messages from the kernel fairly regularly...

BUG: warning at fs/inotify.c:202/set_dentry_child_flags() (Tainted: G     )

Call Trace:
 [<ffffffff800f05b3>] set_dentry_child_flags+0xef/0x14d
 [<ffffffff800f0649>] remove_watch_no_event+0x38/0x47
 [<ffffffff800f0670>] inotify_remove_watch_locked+0x18/0x3b
 [<ffffffff800f07a8>] inotify_rm_wd+0x8a/0xb3
 [<ffffffff800f0d1e>] sys_inotify_rm_watch+0x46/0x63
 [<ffffffff8005d116>] system_call+0x7e/0x83

Version-Release number of selected component (if applicable):

I'm running 2.6.18-128.7.1.el5, but the same code is in the current 5.4 kernel 2.6.18-164.2.1.el5 so I don't think it's been fixed.

How reproducible:

no idea what causes it. there are 100's of users on the machine and we get multiple flurries daily, each of about a dozen of the warnings at a time.

Steps to Reproduce:
1. have a busy machine with lots of users doing whatever crazy things it is that users do
2. wait
  
Actual results:

the above kernel warnings are seen.

Expected results:

no messages seen.

Additional info:

this was fixed upstream by
  http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=0d71bd5993b630a989d15adc2562a9ffe41cd26d
where it looks like the busted-arsed inotify debug/warning code was simply removed.

this same bug was seen and fixed in fedora
  https://bugzilla.redhat.com/show_bug.cgi?id=248355
and there is someone else reporting RHEL x86_64 has the problem in that bz too.
Comment 1 Sotiris Tsimbonis 2009-10-19 11:45:50 UTC 
I confirm seeing this on a fairly busy mail server, running dovecot with a few thousands of users..

# uname -a
Linux mail 2.6.18-164.2.1.el5 #1 SMP Mon Sep 21 04:37:42 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux

# dmesg | grep -c fs/inotify.c:202/set_dentry_child_flags
302

Ubuntu has a similar report too https://bugs.launchpad.net/ubuntu/+source/linux-source-2.6.20/+bug/104837
Comment 2 Sotiris Tsimbonis 2009-10-19 11:48:31 UTC 
BUG: warning at fs/inotify.c:202/set_dentry_child_flags() (Tainted: PF    )

Call Trace:
 [<ffffffff800f578c>] set_dentry_child_flags+0xef/0x14d
 [<ffffffff800f5822>] remove_watch_no_event+0x38/0x47
 [<ffffffff800f5849>] inotify_remove_watch_locked+0x18/0x3b
 [<ffffffff800f5984>] inotify_rm_wd+0x8d/0xb6
 [<ffffffff800f5efa>] sys_inotify_rm_watch+0x46/0x63
 [<ffffffff8005d116>] system_call+0x7e/0x83
Comment 3 Eric Paris 2009-10-19 14:56:08 UTC 
Marking as a duplicate of the same issue.  I believe the other bug is held up looking for people willing to test and confirm the issue is fixed by a beta kernel release.  If you are willing to test please post so in the other BZ.

*** This bug has been marked as a duplicate of bug 499019 ***
Comment 4 Sotiris Tsimbonis 2009-10-19 19:33:22 UTC 
I am willing to test the fix, but unfortunately I am not authorized to access bug #499019.
Comment 5 Chris Ward 2009-10-20 08:10:04 UTC 
@ Sotiris,

I'm working to get you access to bug #499019.

In the mean time, could you confirm whether or not you would be able to test the RHEL 5.5 Beta once its available, if we approve this fix for the release?
Comment 6 Sotiris Tsimbonis 2009-10-20 09:32:35 UTC 
Yeap, my RHN subscription is valid :)