On 09/10/2014 09:40 AM, Mel Gorman wrote: > On Wed, Sep 10, 2014 at 09:12:04AM -0400, Sasha Levin wrote: >> <SNIP, haven't digested the rest> >> >> I've spotted a new trace in overnight fuzzing, it could be related to this issue: >> >> [ 3494.324839] general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC >> [ 3494.332153] Dumping ftrace buffer: >> [ 3494.332153] (ftrace buffer empty) >> [ 3494.332153] Modules linked in: >> [ 3494.332153] CPU: 8 PID: 2727 Comm: trinity-c929 Not tainted 3.17.0-rc4-next-20140909-sasha-00032-gc16d47b #1135 >> [ 3494.332153] task: ffff88047e52b000 ti: ffff8804d491c000 task.ti: ffff8804d491c000 >> [ 3494.332153] RIP: task_numa_work (include/linux/mempolicy.h:177 kernel/sched/fair.c:1956) >> [ 3494.332153] RSP: 0000:ffff8804d491feb8 EFLAGS: 00010206 >> [ 3494.332153] RAX: 0000000000000000 RBX: ffff8804bf4e8000 RCX: 000000000000e8e8 >> [ 3494.343974] RDX: 000000000000000a RSI: 0000000000000000 RDI: ffff8804bd6d4da8 >> [ 3494.343974] RBP: ffff8804d491fef8 R08: ffff8804bf4e84c8 R09: 0000000000000000 >> [ 3494.343974] R10: 00007f53e443c000 R11: 0000000000000001 R12: 00007f53e443c000 >> [ 3494.343974] R13: 000000000000dc51 R14: 006f732e61727478 R15: ffff88047e52b000 >> [ 3494.343974] FS: 00007f53e463f700(0000) GS:ffff880277e00000(0000) knlGS:0000000000000000 >> [ 3494.343974] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b >> [ 3494.369895] CR2: 0000000001670fa8 CR3: 0000000283562000 CR4: 00000000000006a0 >> [ 3494.369895] DR0: 00000000006f0000 DR1: 0000000000000000 DR2: 0000000000000000 >> [ 3494.369895] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 >> [ 3494.380081] Stack: >> [ 3494.380081] ffff8804bf4e80a8 0000000000000014 00007f53e4437000 0000000000000000 >> [ 3494.380081] ffffffff9b976e70 ffff88047e52bbd8 ffff88047e52b000 0000000000000000 >> [ 3494.380081] ffff8804d491ff28 ffffffff95193d84 0000000000000002 ffff8804d491ff58 >> [ 3494.380081] Call Trace: >> [ 3494.380081] task_work_run (kernel/task_work.c:125 (discriminator 1)) >> [ 3494.380081] do_notify_resume (include/linux/tracehook.h:190 arch/x86/kernel/signal.c:758) >> [ 3494.380081] retint_signal (arch/x86/kernel/entry_64.S:918) >> [ 3494.380081] Code: e8 1e e5 01 00 48 89 df 4c 89 e6 e8 a3 2d 13 00 49 89 c6 48 85 c0 0f 84 07 02 00 00 48 c7 45 c8 00 00 00 00 0f 1f 80 00 00 00 00 <49> f7 46 50 00 44 00 00 0f 85 42 01 00 00 49 8b 86 a0 00 00 00 > > Shot in dark, can you test this please? Pagetable teardown can schedule > and I'm wondering if we are trying to add hinting faults to an address > space that is in the process of going away. The TASK_DEAD check is bogus > so replacing it. Mel, I ran today's -next with both of your patches, but the issue still remains: [ 3114.540976] kernel BUG at include/asm-generic/pgtable.h:724! [ 3114.541857] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC [ 3114.543112] Dumping ftrace buffer: [ 3114.544056] (ftrace buffer empty) [ 3114.545000] Modules linked in: [ 3114.545717] CPU: 18 PID: 30217 Comm: trinity-c617 Tainted: G W 3.17.0-rc4-next-20140910-sasha-00032-g6825fb5-dirty #1137 [ 3114.548058] task: ffff880415050000 ti: ffff88076f584000 task.ti: ffff88076f584000 [ 3114.549284] RIP: 0010:[<ffffffff952e527a>] [<ffffffff952e527a>] change_pte_range+0x4ea/0x4f0 [ 3114.550028] RSP: 0000:ffff88076f587d68 EFLAGS: 00010246 [ 3114.550028] RAX: 0000000314625900 RBX: 0000000041218000 RCX: 0000000000000100 [ 3114.550028] RDX: 0000000314625900 RSI: 0000000041218000 RDI: 0000000314625900 [ 3114.550028] RBP: ffff88076f587dc8 R08: ffff8802cf973600 R09: 0000000000b50000 [ 3114.550028] R10: 0000000000032c01 R11: 0000000000000008 R12: ffff8802a81070c0 [ 3114.550028] R13: 8000000000000025 R14: 0000000041343000 R15: ffffc00000000fff [ 3114.550028] FS: 00007fabb91c8700(0000) GS:ffff88025ec00000(0000) knlGS:0000000000000000 [ 3114.550028] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 3114.550028] CR2: 00007fffdb7678e8 CR3: 0000000713935000 CR4: 00000000000006a0 [ 3114.550028] DR0: 00000000006f0000 DR1: 0000000000000000 DR2: 0000000000000000 [ 3114.550028] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000050602 [ 3114.550028] Stack: [ 3114.550028] 0000000000000001 0000000314625900 0000000000000018 ffff8802685f2260 [ 3114.550028] 0000000016840000 ffff8802cf973600 ffff880616840000 0000000041343000 [ 3114.550028] ffff880108805048 0000000041005000 0000000041200000 0000000041343000 [ 3114.550028] Call Trace: [ 3114.550028] [<ffffffff952e5534>] change_protection+0x2b4/0x4e0 [ 3114.550028] [<ffffffff952ff24b>] change_prot_numa+0x1b/0x40 [ 3114.550028] [<ffffffff951adf16>] task_numa_work+0x1f6/0x330 [ 3114.550028] [<ffffffff95193de4>] task_work_run+0xc4/0xf0 [ 3114.550028] [<ffffffff95071477>] do_notify_resume+0x97/0xb0 [ 3114.550028] [<ffffffff9850f06a>] int_signal+0x12/0x17 [ 3114.550028] Code: 66 90 48 8b 7d b8 e8 e6 88 22 03 48 8b 45 b0 e9 6f ff ff ff 0f 1f 44 00 00 0f 0b 66 0f 1f 44 00 00 0f 0b 66 0f 1f 44 00 00 0f 0b <0f> 0b 0f 0b 0f 0b 66 66 66 66 90 55 48 89 e5 41 57 49 89 d7 41 [ 3114.550028] RIP [<ffffffff952e527a>] change_pte_range+0x4ea/0x4f0 [ 3114.550028] RSP <ffff88076f587d68> Thanks, Sasha -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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