Latest working kernel version: 2.6.28 Earliest failing kernel version: 2.6.29-rc3 Distribution: ubuntu gutsy Hardware Environment: thinkpad T60p Software Environment: lockdep enabled Problem Description: after suspend/resume, circular lock dependency warning appears in dmesg output: [ 2108.325226] ACPI: Preparing to enter system sleep state S3 [ 2108.345297] Disabling non-boot CPUs ... [ 2108.345692] [ 2108.345694] ======================================================= [ 2108.345697] [ INFO: possible circular locking dependency detected ] [ 2108.345702] 2.6.29-rc3-mst-debug #94 [ 2108.345705] ------------------------------------------------------- [ 2108.345708] bash/6787 is trying to acquire lock: [ 2108.345712] (&per_cpu(cpu_policy_rwsem, cpu)){----}, at: [<c02c02b1>] lock_policy_rwsem_write+0x31/0x70 [ 2108.345727] [ 2108.345729] but task is already holding lock: [ 2108.345732] (&cpu_hotplug.lock){--..}, at: [<c012d7ea>] cpu_hotplug_begin+0x1a/0x50 [ 2108.345741] [ 2108.345742] which lock already depends on the new lock. [ 2108.345744] Full message and .config will attached. Steps to reproduce: suspend, resume.
Created attachment 20040 [details] full dmesg output including the warning
Created attachment 20041 [details] kernel 2.6.29-rc3 .config with lockdep enabled
References : http://lkml.org/lkml/2009/2/9/205
On Sunday 15 February 2009, Michael S. Tsirkin wrote: > It's still there in -rc5. > > On Sat, Feb 14, 2009 at 10:38 PM, Rafael J. Wysocki <rjw@sisk.pl> wrote: > > This message has been generated automatically as a part of a report > > of recent regressions. > > > > The following bug entry is on the current list of known regressions > > from 2.6.28. Please verify if it still should be listed and let me know > > (either way). > > > > > > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=12574 > > Subject : possible circular locking dependency detected > > Submitter : Michael S. Tsirkin <m.s.tsirkin@gmail.com> > > Date : 2009-01-29 11:35 (17 days old) > > References : http://lkml.org/lkml/2009/2/9/205
On Tuesday 03 March 2009, Michael S. Tsirkin wrote: > On Tue, Mar 3, 2009 at 9:25 PM, Rafael J. Wysocki <rjw@sisk.pl> wrote: > > This message has been generated automatically as a part of a report > > of recent regressions. > > > > The following bug entry is on the current list of known regressions > > from 2.6.28. Please verify if it still should be listed and let me know > > (either way). > > > > > > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=12574 > > Subject : possible circular locking dependency detected > > Submitter : Michael S. Tsirkin <m.s.tsirkin@gmail.com> > > Date : 2009-01-29 11:35 (34 days old) > > References : http://lkml.org/lkml/2009/2/9/205 > > > > > > > > I don't seem to observe this warning in v2.6.29-rc6 anymore.
I see this again in 2.6.29-rc7. Reopening.
as the problem exists in 2.6.29-rc3 while it doesn't in 2.6.28 could you please use git-bisect to see which commit introduces this bug?
> > as the problem exists in 2.6.29-rc3 while it doesn't in 2.6.28 > could you please use git-bisect to see which commit introduces this bug? > Is this really necessary? I am not sure I can get my hands on this machine. It seems pretty clear where the circular dependency is - the real question is IMO what the right fix is. <div dir="ltr"><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">as the problem exists in 2.6.29-rc3 while it doesn't in 2.6.28<br> could you please use git-bisect to see which commit introduces this bug?<br> </blockquote></div><br>Is this really necessary? I am not sure I can get my hands on this machine.<br>It seems pretty clear where the circular dependency is -<br>the real question is IMO what the right fix is.<br><br></div>
On Monday 16 March 2009, Michael S. Tsirkin wrote: > On Sat, Mar 14, 2009 at 08:05:29PM +0100, Rafael J. Wysocki wrote: > > This message has been generated automatically as a part of a report > > of recent regressions. > > > > The following bug entry is on the current list of known regressions > > from 2.6.28. Please verify if it still should be listed and let me know > > (either way). > > > > > > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=12574 > > Subject : possible circular locking dependency detected > > Submitter : Michael S. Tsirkin <m.s.tsirkin@gmail.com> > > Date : 2009-01-29 11:35 (45 days old) > > References : http://lkml.org/lkml/2009/2/9/205 > > > > It's still there in rc8.
It seems we can't proceed any further here. Closing.