On 02/28/2014 12:20 PM, Sasha Levin wrote: > On 02/21/2014 08:10 PM, Sasha Levin wrote: >> On 02/21/2014 06:51 PM, Kirill A. Shutemov wrote: >>> On Fri, Feb 21, 2014 at 05:46:36PM -0500, Sasha Levin wrote: >>>> >Hi all, >>>> > >>>> >While fuzzing with trinity inside a KVM tools guest running latest -next >>>> >kernel I've stumbled on the following (now with pretty line numbers!) spew: >>>> > >>>> >[ 746.125099] kernel BUG at mm/huge_memory.c:1371! >>> It "VM_BUG_ON_PAGE(!PageHead(page), page);", correct? >>> I don't see dump_page() output. >> >> Right. However, I'm not seeing the dump_page() output in the log. >> >> I see that dump_page() has been modified not long ago, I'm looking into it. > > Alright, here we go: > > [ 3323.062742] page:ffffea00080f0000 count:3 mapcount:0 mapping:ffff8802292ee0e1 index:0x7fa2e6800 > [ 3323.065978] page flags: 0x16fffff80090018(uptodate|dirty|swapcache|swapbacked) > [ 3323.068535] ------------[ cut here ]------------ > [ 3323.069669] kernel BUG at mm/huge_memory.c:1371! > [ 3323.070961] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC > [ 3323.071028] Dumping ftrace buffer: > [ 3323.071028] (ftrace buffer empty) > [ 3323.071028] Modules linked in: > [ 3323.071028] CPU: 101 PID: 48284 Comm: trinity-c101 Tainted: G W 3.14.0-rc4-next-20140228-sasha-00011-g4077c67 #25 > [ 3323.071028] task: ffff8800c2718000 ti: ffff8800c26ec000 task.ti: ffff8800c26ec000 > [ 3323.071028] RIP: 0010:[<ffffffff812c083a>] [<ffffffff812c083a>] zap_huge_pmd+0x17a/0x200 > [ 3323.071028] RSP: 0018:ffff8800c26edc78 EFLAGS: 00010246 > [ 3323.071028] RAX: ffff88022febc000 RBX: ffff8800c26edde8 RCX: 0000000000000040 > [ 3323.071028] RDX: 0000000000000000 RSI: ffff8800c2718cc0 RDI: 000000000203c000 > [ 3323.071028] RBP: ffff8800c26edcb8 R08: 0000000000000000 R09: 0000000000000000 > [ 3323.071028] R10: 0000000000000001 R11: 0000000000000001 R12: ffffea0008b9e240 > [ 3323.071028] R13: ffffea00080f0000 R14: 00007fa2e6800000 R15: 00007fa2ffffffff > [ 3323.071028] FS: 00007fa31e1b8700(0000) GS:ffff880230600000(0000) knlGS:0000000000000000 > [ 3323.071028] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > [ 3323.071028] CR2: 00007fa31e1e8990 CR3: 0000000005c25000 CR4: 00000000000006e0 > [ 3323.071028] DR0: 0000000000698000 DR1: 0000000000698000 DR2: 0000000000698000 > [ 3323.071028] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 > [ 3323.071028] Stack: > [ 3323.071028] 00000000000004de ffff88022e2139d0 ffff8800c26edcb8 ffff88021b7ef9a0 > [ 3323.071028] 00007fa2e6800000 00007fa300000000 ffff8800c26edde8 00007fa2ffffffff > [ 3323.071028] ffff8800c26edd48 ffffffff812800c6 ffffea0008454540 00007fa2e6a00000 > [ 3323.071028] Call Trace: > [ 3323.071028] [<ffffffff812800c6>] unmap_page_range+0x2c6/0x410 > [ 3323.071028] [<ffffffff81280301>] unmap_single_vma+0xf1/0x110 > [ 3323.071028] [<ffffffff81280381>] unmap_vmas+0x61/0xa0 > [ 3323.071028] [<ffffffff812875e0>] exit_mmap+0xd0/0x170 > [ 3323.071028] [<ffffffff811387a7>] mmput+0x77/0xe0 > [ 3323.071028] [<ffffffff8113c80d>] exit_mm+0x18d/0x1a0 > [ 3323.071028] [<ffffffff811ecea5>] ? acct_collect+0x175/0x1b0 > [ 3323.071028] [<ffffffff8113ec1a>] do_exit+0x26a/0x510 > [ 3323.071028] [<ffffffff8113ef61>] do_group_exit+0xa1/0xe0 > [ 3323.071028] [<ffffffff8113efb2>] SyS_exit_group+0x12/0x20 > [ 3323.071028] [<ffffffff8439f720>] tracesys+0xdd/0xe2 > [ 3323.071028] Code: 00 eb fe 66 0f 1f 44 00 00 48 8b 03 f0 48 81 80 60 03 00 00 00 fe ff ff 49 8b 45 00 f6 c4 40 75 18 31 f6 4c 89 ef e8 f6 1f f9 ff <0f> 0b 0f 1f 40 00 eb fe 66 0f 1f 44 00 00 48 8b 03 f0 48 ff 48 > [ 3323.071028] RIP [<ffffffff812c083a>] zap_huge_pmd+0x17a/0x200 > [ 3323.071028] RSP <ffff8800c26edc78> This is still happening in -next. Anything else I can provide that'll be useful? Thanks, Sasha -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>