Hugh Dickins wrote: [snip] > > BUG: unable to handle kernel paging request at 6b6b6b8b > IP: [<7817078f>] memrlimit_cgroup_uncharge_as+0x18/0x29 > *pde = 00000000 > Oops: 0000 [#1] PREEMPT SMP > last sysfs file: /sys/devices/system/cpu/cpu1/cache/index2/shared_cpu_map > Modules linked in: acpi_cpufreq snd_pcm_oss snd_mixer_oss snd_seq snd_seq_device thermal ac battery button > > Pid: 22500, comm: swapoff Not tainted (2.6.26-rc8-mm1 #7) > EIP: 0060:[<7817078f>] EFLAGS: 00010206 CPU: 0 > EIP is at memrlimit_cgroup_uncharge_as+0x18/0x29 > EAX: 6b6b6b6b EBX: 7963215c ECX: 7c032000 EDX: 0025e000 > ESI: 96902518 EDI: 9fbb1aa0 EBP: 7c033e9c ESP: 7c033e9c > DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 > Process swapoff (pid: 22500, ti=7c032000 task=907e2b70 task.ti=7c032000) > Stack: 7c033edc 78161323 9fbb1aa0 0000025e ffffff77 7c033ecc 96902518 00000000 > ffffffff 7c033ec8 00000000 00000089 7963215c 9fbb1aa0 9fbb1b28 a272f040 > 7c033ef4 781226b1 9fbb1aa0 9fbb1aa0 790fa884 a272f0c8 7c033f80 78165ce3 > Call Trace: > [<78161323>] ? exit_mmap+0xaf/0x133 > [<781226b1>] ? mmput+0x4c/0xba > [<78165ce3>] ? try_to_unuse+0x20b/0x3f5 > [<78371534>] ? _spin_unlock+0x22/0x3c > [<7816636a>] ? sys_swapoff+0x17b/0x37c > [<78102d95>] ? sysenter_past_esp+0x6a/0xa5 > ======================= > Code: 24 0c 00 00 8b 40 20 52 83 c0 0c 50 e8 ad a6 fd ff c9 c3 55 89 e5 8b 45 08 8b 55 0c 8b 80 30 02 00 00 c1 e2 0c 8b 80 24 0c 00 00 <8b> 40 20 52 83 c0 0c 50 e8 e6 a6 fd ff 58 5a c9 c3 55 89 e5 8b > EIP: [<7817078f>] memrlimit_cgroup_uncharge_as+0x18/0x29 SS:ESP 0068:7c033e9c Hi, Hugh, I am unable to reproduce the problem, but I do have an initial hypothesis CPU0 CPU1 try_to_unuse task 1 stars exiting look at mm = task1->mm .. increment mm_users task 1 exits mm->owner needs to be updated, but no new owner is found (mm_users > 1, but no other task has task->mm = task1->mm) mm_update_next_owner() leaves grace period user count drops, call mmput(mm) task 1 freed dereferencing mm->owner fails I do have a potential solution in mind, but I want to make sure my hypothesis is correct. -- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers