Unfortunately I received 2 other kdumps from the same user and it looks like that other 2 kdumps were happening because of a NULL dereference (3.2.0-79). I asked them to test latest 3.2 kernel + the fix I commented above.
User still faced kdumps with latest 3.2 but only with khungtask complaining about soft lockups. A first look into the dumps showed a lock contention: crash> bt ffff883f70c78000 PID: 41940 TASK: ffff883f70c78000 CPU: 13 COMMAND: "java" #0 [ffff883f69093d98] __schedule at ffffffff81666f4a #1 [ffff883f69093e20] schedule at ffffffff816675cf #2 [ffff883f69093e30] rwsem_down_failed_common at ffffffff8166940d #3 [ffff883f69093ea0] rwsem_down_write_failed at ffffffff816694c3 #4 [ffff883f69093eb0] call_rwsem_down_write_failed at ffffffff8131fb43 #5 [ffff883f69093f10] sys_mprotect at ffffffff811488f0 #6 [ffff883f69093f80] system_call_fastpath at ffffffff81671c62 RIP: 00007f1adc172cc7 RSP: 00007f1adcc89c60 RFLAGS: 00010297 RAX: 000000000000000a RBX: ffffffff81671c62 RCX: 00000000ef038c60 RDX: 0000000000000003 RSI: 0000000000002000 RDI: 00007f1ad49bc000 RBP: 0000000000002010 R8: 00000000009be000 R9: 0000000000000000 R10: 00000000009bc000 R11: 0000000000000206 R12: 0000000000000ac0 R13: 00007f1ad49bb540 R14: 0000000000002000 R15: 00007f1ad4000078 ORIG_RAX: 000000000000000a CS: 0033 SS: 002b on the task monitored by khungtask thread. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1534413 Title: Precise: lockup during fadvise syscall with POSIX_FADV_DONTNEED Status in linux package in Ubuntu: In Progress Bug description: It was brought to my knowledge a kernel dump (3.2.0-79) with the following stack trace: """ [14277.952072] usb 3-1: USB disconnect, device number 3 [15388.602790] NOHZ: local_softirq_pending 02 [15404.593795] NOHZ: local_softirq_pending 02 [15436.575787] NOHZ: local_softirq_pending 02 [15452.566802] NOHZ: local_softirq_pending 02 [15456.564528] NOHZ: local_softirq_pending 02 [15564.503842] NOHZ: local_softirq_pending 02 [15584.492538] NOHZ: local_softirq_pending 02 [15588.490302] NOHZ: local_softirq_pending 02 [15632.465563] NOHZ: local_softirq_pending 02 [15659.014629] NOHZ: local_softirq_pending 02 [15956.371298] INFO: task jsvc:57263 blocked for more than 120 seconds. [15956.375347] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [15956.383487] jsvc D ffffffff81806200 0 57263 9495 0x00000000 [15956.383493] ffff883e849c3d08 0000000000000082 ffff883e849c3ca8 000000008104f624 [15956.383502] ffff883e849c3fd8 ffff883e849c3fd8 ffff883e849c3fd8 0000000000012800 [15956.383509] ffff881f72db9700 ffff883e0c4e2e00 ffff883e849c3cf8 7fffffffffffffff [15956.383518] Call Trace: [15956.383534] [<ffffffff81662c0f>] schedule+0x3f/0x60 [15956.383539] [<ffffffff8166324d>] schedule_timeout+0x29d/0x310 [15956.383547] [<ffffffff810388be>] ? physflat_send_IPI_mask+0xe/0x10 [15956.383554] [<ffffffff81032068>] ? native_smp_send_reschedule+0x48/0x60 [15956.383560] [<ffffffff8103ec29>] ? default_spin_lock_flags+0x9/0x10 [15956.383564] [<ffffffff81662a4f>] wait_for_common+0xdf/0x180 [15956.383572] [<ffffffff81060ac0>] ? try_to_wake_up+0x200/0x200 [15956.383576] [<ffffffff81662bcd>] wait_for_completion+0x1d/0x20 [15956.383585] [<ffffffff8108757e>] flush_work+0x2e/0x40 [15956.383589] [<ffffffff810838b0>] ? wake_up_worker+0x30/0x30 [15956.383593] [<ffffffff81087813>] schedule_on_each_cpu+0xc3/0x110 [15956.383602] [<ffffffff81127365>] lru_add_drain_all+0x15/0x20 [15956.383607] [<ffffffff8111e189>] sys_fadvise64_64+0x189/0x270 [15956.383610] [<ffffffff8111e27e>] sys_fadvise64+0xe/0x10 [15956.383619] [<ffffffff8166d2c2>] system_call_fastpath+0x16/0x1b [15956.383622] Kernel panic - not syncing: hung_task: blocked tasks [15956.388083] Pid: 178, comm: khungtaskd Tainted: G W 3.2.0-79-generic #115-Ubuntu [15956.397273] Call Trace: [15956.401783] [<ffffffff8164c005>] panic+0x91/0x1a4 [15956.406527] [<ffffffff810d97c2>] check_hung_task+0xb2/0xc0 [15956.411393] [<ffffffff810d98eb>] check_hung_uninterruptible_tasks+0x11b/0x140 [15956.421117] [<ffffffff810d9910>] ? check_hung_uninterruptible_tasks+0x140/0x140 [15956.431847] [<ffffffff810d995f>] watchdog+0x4f/0x60 [15956.437524] [<ffffffff8108b99c>] kthread+0x8c/0xa0 [15956.443145] [<ffffffff8166f434>] kernel_thread_helper+0x4/0x10 [15956.448830] [<ffffffff8108b910>] ? flush_kthread_worker+0xa0/0xa0 [15956.454700] [<ffffffff8166f430>] ? gs_change+0x13/0x13 """ Analysis being made on the comments... To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1534413/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
