BUG at /usr/src/linux-2.6/mm/filemap.c:202 (was: perf: use after free in perf_remove_from_context)

[Peter Zijlstra]

On Thu, May 15, 2014 at 08:11:02PM +0200, Peter Zijlstra wrote:
> On Mon, May 12, 2014 at 11:42:33AM -0400, Sasha Levin wrote:
> > Hi all,
> > 
> > While fuzzing with trinity inside a KVM tools guest running the latest -next
> > kernel I've stumbled on the following spew. Maybe related to the very recent
> > change in freeing on task exit?
> > 
> 
> While fuzzing to reproduce; I hit this one, is it a known one or should
> I go poke the right people about it?
> 
> ---
> [ 5823.689985] ------------[ cut here ]------------
> [ 5823.690004] WARNING: CPU: 3 PID: 2508 at /usr/src/linux-2.6/lib/list_debug.c:59 __list_del_entry+0xa1/0xd0()
> [ 5823.690004] list_del corruption. prev->next should be ffff880131111de0, but was 6b6b6b6b6b6b6b6b
> [ 5823.690004] Modules linked in:
> [ 5823.690004] CPU: 3 PID: 2508 Comm: trinity-main Not tainted 3.15.0-rc5-01700-g505011124ad0-dirty #1072
> [ 5823.690004] Hardware name: Supermicro X8DTN/X8DTN, BIOS 4.6.3 01/08/2010
> [ 5823.690004]  0000000000000009 ffff880432709ca8 ffffffff81681aa2 ffff880432709cf0
> [ 5823.690004]  ffff880432709ce0 ffffffff8109807c ffff880131111de0 ffff880131111dc8
> [ 5823.690004]  0000000000000286 ffff8800b9dd5618 ffff88023699b720 ffff880432709d40
> [ 5823.690004] Call Trace:
> [ 5823.690004]  [<ffffffff81681aa2>] dump_stack+0x4e/0x7a
> [ 5823.690004]  [<ffffffff8109807c>] warn_slowpath_common+0x8c/0xc0
> [ 5823.690004]  [<ffffffff8109816c>] warn_slowpath_fmt+0x4c/0x50
> [ 5823.690004]  [<ffffffff810ec8bf>] ? do_raw_spin_lock+0x13f/0x160
> [ 5823.690004]  [<ffffffff8138c661>] __list_del_entry+0xa1/0xd0
> [ 5823.690004]  [<ffffffff8138c69d>] list_del+0xd/0x30
> [ 5823.690004]  [<ffffffff810dfa71>] remove_wait_queue+0x31/0x50
> [ 5823.690004]  [<ffffffff812152aa>] ep_unregister_pollwait.isra.9+0x6a/0xb0
> [ 5823.690004]  [<ffffffff81215268>] ? ep_unregister_pollwait.isra.9+0x28/0xb0
> [ 5823.690004]  [<ffffffff8121531f>] ep_remove+0x2f/0xe0
> [ 5823.690004]  [<ffffffff81215705>] eventpoll_release_file+0x65/0xa0
> [ 5823.690004]  [<ffffffff811cf259>] __fput+0x1d9/0x1e0
> [ 5823.690004]  [<ffffffff811cf2ae>] ____fput+0xe/0x10
> [ 5823.690004]  [<ffffffff810b91f4>] task_work_run+0xc4/0xe0
> [ 5823.690004]  [<ffffffff8109a544>] do_exit+0x2d4/0xa90
> [ 5823.690004]  [<ffffffff813825c4>] ? lockdep_sys_exit_thunk+0x35/0x67
> [ 5823.690004]  [<ffffffff8109ae2c>] do_group_exit+0x4c/0xc0
> [ 5823.690004]  [<ffffffff8109aeb7>] SyS_exit_group+0x17/0x20
> [ 5823.690004]  [<ffffffff8168a2c2>] system_call_fastpath+0x16/0x1b
> [ 5823.690004] ---[ end trace 515b7fa3169c0906 ]---

I just hit this one, which is somewhat similar:

---
[ 4003.295259] ------------[ cut here ]------------
[ 4003.297195] kernel BUG at /usr/src/linux-2.6/mm/filemap.c:202!
[ 4003.297195] invalid opcode: 0000 [#1] PREEMPT SMP 
[ 4003.297195] Modules linked in:
[ 4003.297195] CPU: 0 PID: 9360 Comm: trinity-c92 Not tainted 3.15.0-rc5-01700-g505011124ad0-dirty #1081
[ 4003.297195] Hardware name: Supermicro X8DTN/X8DTN, BIOS 4.6.3 01/08/2010
[ 4003.297195] task: ffff88042a9db900 ti: ffff88042aa7a000 task.ti: ffff88042aa7a000
[ 4003.297195] RIP: 0010:[<ffffffff81174af1>]  [<ffffffff81174af1>] __delete_from_page_cache+0x2a1/0x2b0
[ 4003.297195] RSP: 0018:ffff88042aa7bb30  EFLAGS: 00010046
[ 4003.297195] RAX: 0000000000000000 RBX: 0000000000000003 RCX: ffff88019dcd46a0
[ 4003.297195] RDX: 0000000000000146 RSI: ffffffff81a651f7 RDI: ffffffff81a2e091
[ 4003.297195] RBP: ffff88042aa7bb78 R08: 000000000000004e R09: ffff8801c4efd138
[ 4003.297195] R10: 0000000000000012 R11: ffff88042aa7bb48 R12: ffffea000828c280
[ 4003.297195] R13: ffff8801bc9a0890 R14: 0000000000000000 R15: ffff8801bc9a0898
[ 4003.297195] FS:  00007f984ad54700(0000) GS:ffff880237c00000(0000) knlGS:0000000000000000
[ 4003.297195] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 4003.297195] CR2: 00007f9847813000 CR3: 0000000001c0e000 CR4: 00000000000007f0
[ 4003.297195] Stack:
[ 4003.297195]  ffff8801bc9a08a8 ffff8801bc9a08a8 ffff8801c4efd138 ffff8801c4efd1d0
[ 4003.297195]  ffffea000828c280 ffff8801bc9a08a8 0000000000000000 ffffffffffffffff
[ 4003.297195]  000000000000004e ffff88042aa7bba0 ffffffff81174c98 ffffea000828c280
[ 4003.297195] Call Trace:
[ 4003.297195]  [<ffffffff81174c98>] delete_from_page_cache+0x48/0x80
[ 4003.297195]  [<ffffffff81182d6b>] truncate_inode_page+0x5b/0x90
[ 4003.297195]  [<ffffffff8118d06a>] shmem_undo_range+0x2fa/0x6e0
[ 4003.297195]  [<ffffffff8118d464>] shmem_truncate_range+0x14/0x30
[ 4003.297195]  [<ffffffff8118d67d>] shmem_evict_inode+0xed/0x150
[ 4003.297195]  [<ffffffff811ea377>] evict+0xa7/0x170
[ 4003.297195]  [<ffffffff811eaaa5>] iput+0x105/0x190
[ 4003.297195]  [<ffffffff811e51c8>] dentry_kill+0x268/0x2e0
[ 4003.297195]  [<ffffffff811e54e9>] dput+0x69/0x110
[ 4003.297195]  [<ffffffff811cf66c>] __fput+0x16c/0x1e0
[ 4003.297195]  [<ffffffff811cf72e>] ____fput+0xe/0x10
[ 4003.297195]  [<ffffffff810b91e7>] task_work_run+0xa7/0xe0
[ 4003.297195]  [<ffffffff8109a554>] do_exit+0x2d4/0xa90
[ 4003.297195]  [<ffffffff8168b351>] ? retint_swapgs+0xe/0x13
[ 4003.297195]  [<ffffffff8109ae3c>] do_group_exit+0x4c/0xc0
[ 4003.297195]  [<ffffffff8109aec7>] SyS_exit_group+0x17/0x20
[ 4003.297195]  [<ffffffff8168a742>] system_call_fastpath+0x16/0x1b
[ 4003.297195] Code: 45 d0 75 29 4c 89 30 e9 b0 fe ff ff 66 0f 1f 44 00 00 48 8b 75 c8 4c 89 ff e8 0c 71 20 00 84 c0 0f 85 96 fe ff ff e9 79 fe ff ff <0f> 0b e8 fe a7 50 00 0f 1f 84 00 00 00 00 00 66 66 66 66 90 55 
[ 4003.297195] RIP  [<ffffffff81174af1>] __delete_from_page_cache+0x2a1/0x2b0
[ 4003.297195]  RSP <ffff88042aa7bb30>
[ 4003.297195] ---[ end trace 2530b701678d4601 ]---

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