On Mon, Dec 23, 2013 at 02:30:54PM -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 spew. > > page = pmd_page(orig_pmd); > page_remove_rmap(page); > VM_BUG_ON(page_mapcount(page) < 0); > add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); > VM_BUG_ON(!PageHead(page)); <=== HERE > atomic_long_dec(&tlb->mm->nr_ptes); > spin_unlock(ptl); > tlb_remove_page(tlb, page); > > [ 265.474585] kernel BUG at mm/huge_memory.c:1440! Could you dump_page() on the bug? > [ 265.475129] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC > [ 265.476684] Dumping ftrace buffer: > [ 265.477144] (ftrace buffer empty) > [ 265.478398] Modules linked in: > [ 265.478807] CPU: 8 PID: 11344 Comm: trinity-c206 Tainted: G W 3.13.0-rc5-ne > xt-20131223-sasha-00015-gec22156-dirty #8 > [ 265.480172] task: ffff8801cb573000 ti: ffff8801cbd3a000 task.ti: ffff8801cbd3a000 > [ 265.480172] RIP: 0010:[<ffffffff812c7f70>] [<ffffffff812c7f70>] zap_huge_pmd+0x170/0 > x1f0 > [ 265.480172] RSP: 0000:ffff8801cbd3bc78 EFLAGS: 00010246 > [ 265.480172] RAX: 015fffff80090018 RBX: ffff8801cbd3bde8 RCX: ffffffffffffff9c > [ 265.480172] RDX: ffffffffffffffff RSI: 0000000000000008 RDI: ffff8800bffd2000 > [ 265.480172] RBP: ffff8801cbd3bcb8 R08: 0000000000000000 R09: 0000000000000000 > [ 265.480172] R10: 0000000000000001 R11: 0000000000000000 R12: ffffea0002856740 > [ 265.480172] R13: ffffea0002d50000 R14: 00007ff915000000 R15: 00007ff930e48fff > [ 265.480172] FS: 00007ff934899700(0000) GS:ffff88014d400000(0000) knlGS:0000000000000 > 000 > [ 265.480172] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > [ 265.480172] CR2: 00007ff93428a000 CR3: 000000010babe000 CR4: 00000000000006e0 > [ 265.480172] Stack: > [ 265.480172] 00000000000004dd ffff8801ccbfbb60 ffff8801cbd3bcb8 ffff8801cbb15540 > [ 265.480172] 00007ff915000000 00007ff930e49000 ffff8801cbd3bde8 00007ff930e48fff > [ 265.480172] ffff8801cbd3bd48 ffffffff812885b6 ffff88005f5d20c0 00007ff915200000 > [ 265.480172] Call Trace: > [ 265.480172] [<ffffffff812885b6>] unmap_page_range+0x2c6/0x410 > [ 265.480172] [<ffffffff81288801>] unmap_single_vma+0x101/0x120 > [ 265.480172] [<ffffffff81288881>] unmap_vmas+0x61/0xa0 > [ 265.480172] [<ffffffff8128f730>] exit_mmap+0xd0/0x170 > [ 265.480172] [<ffffffff81138860>] mmput+0x70/0xe0 > [ 265.480172] [<ffffffff8113c89d>] exit_mm+0x18d/0x1a0 > [ 265.480172] [<ffffffff811ea355>] ? acct_collect+0x175/0x1b0 > [ 265.480172] [<ffffffff8113ed0f>] do_exit+0x26f/0x520 > [ 265.480172] [<ffffffff8113f069>] do_group_exit+0xa9/0xe0 > [ 265.480172] [<ffffffff8113f0b7>] SyS_exit_group+0x17/0x20 > [ 265.480172] [<ffffffff845f10d0>] tracesys+0xdd/0xe2 > [ 265.480172] Code: 0f 0b 66 0f 1f 84 00 00 00 00 00 eb fe 66 0f 1f 44 00 > 00 48 8b 03 f0 48 81 80 50 03 00 00 00 fe ff ff 49 8b 45 00 f6 c4 40 75 10 > <0f> 0b 66 0f 1f 44 00 00 eb fe 66 0f 1f 44 00 00 48 8b 03 f0 48 > [ 265.480172] RIP [<ffffffff812c7f70>] zap_huge_pmd+0x170/0x1f0 > [ 265.480172] RSP <ffff8801cbd3bc78> > > > Thanks, > Sasha > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- Kirill A. Shutemov -- 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>