On poniedziałek, 5 września 2011 o 11:07:55 Srivatsa S. Bhat wrote: > On 09/01/2011 12:10 AM, Maciej Rutecki wrote: > > On środa, 24 sierpnia 2011 o 15:44:55 Srivatsa S. Bhat wrote: > >> Hi, > >> > >> While running stressful cpu hotplug tests along with kernel compilation > >> running in background, soft-lockups are detected on multiple CPUs. > >> Sometimes this also leads to hard lockups and kernel panic. > >> All the soft-lockups seem to occur at vfsmount_lock_local_cpu() or other > >> VFS callpaths. > >> > >> > >> [37108.410813] BUG: soft lockup - CPU#5 stuck for 22s! [cc1:29669] > >> <snip> > >> [37108.694781] Call Trace: > >> [37108.697306] [<ffffffff81199e70>] ? > >> vfsmount_lock_local_lock_cpu+0x70/0x70 [37108.704258] > >> [<ffffffff81187cb5>] path_init+0x315/0x400 > >> [37108.709558] [<ffffffff8127c398>] ? __raw_spin_lock_init+0x38/0x70 > >> [37108.715812] [<ffffffff8118961c>] path_openat+0x8c/0x3f0 > >> [37108.721203] [<ffffffff81012129>] ? sched_clock+0x9/0x10 > >> [37108.726597] [<ffffffff8109416d>] ? sched_clock_cpu+0xcd/0x110 > >> [37108.732508] [<ffffffff810a178d>] ? trace_hardirqs_off+0xd/0x10 > >> [37108.738498] [<ffffffff8109421f>] ? local_clock+0x6f/0x80 > >> [37108.743970] [<ffffffff81189a99>] do_filp_open+0x49/0xa0 > >> [37108.749362] [<ffffffff811982f3>] ? alloc_fd+0xc3/0x210 > >> [37108.754665] [<ffffffff8152584b>] ? _raw_spin_unlock+0x2b/0x40 > >> [37108.760575] [<ffffffff811982f3>] ? alloc_fd+0xc3/0x210 > >> [37108.765875] [<ffffffff81179607>] do_sys_open+0x107/0x1e0 > >> [37108.771352] [<ffffffff810d610f>] ? audit_syscall_entry+0x1bf/0x1f0 > >> [37108.777695] [<ffffffff81179720>] sys_open+0x20/0x30 > >> [37108.782741] [<ffffffff8152e202>] system_call_fastpath+0x16/0x1b > >> > >> Kernel version: 3.0.1, 3.0.3 > >> Hardware: Dual socket quad-core hyper-threaded Intel x86 machine > >> Scenario: > >> (a) Stressful cpu hotplug tests + kernel compilation > >> > >> (b) IRQ balancing had been disabled and all the IRQs were made to be > >> > >> routed to CPU 0 (except the ones that couldn't be routed). > >> > >> (c) Lockdep was enabled during kernel configuration. > >> > >> Steps (b) and (c) were done to dig deeper into the issue. However the > >> same issue was observed by just doing step (a). > >> > >> Definitely there seems to be a race condition occurring here, because > >> this issue is hit after sometime, after starting the tests. And the > >> time it takes to hit the issue increases as we increase the number of > >> debug print statements. In some cases (especially when the number of > >> debug print statements were quite high), the stress on the machine had > >> to be increased in order to hit the issue within measurable time. In my > >> tests, a maximum of about 2 to 2.5 hours was sufficient, to hit this > >> bug. > >> > >> Please find the console log attached with this mail. > >> > >> Any ideas on how to go about fixing this bug? > > > > It is a regression? > > Hi Maciej, > > Thank you for taking a look. > Yes, it seems to be a regression. I tested out kernel 2.6.39.3 with similar > test cases for quite a long time, and it did not hit any soft-lockup > issues. Thanks for the answer. I create bug entry: https://bugzilla.kernel.org/show_bug.cgi?id=42402 Regards -- Maciej Rutecki http://www.maciek.unixy.pl _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
