On Fri, Apr 26, 2013 at 07:40:20PM +0200, Sedat Dilek wrote: > Oops, NULL-pointer-deref [ __queue_work() ] > > [ 25.974932] BUG: unable to handle kernel NULL pointer dereference > at 0000000000000100 > [ 25.974944] IP: [<ffffffff81077502>] __queue_work+0x32/0x3d0 So, 0x100 deref near the top of the function. ... > [ 25.975037] RIP: 0010:[<ffffffff81077502>] [<ffffffff81077502>] > __queue_work+0x32/0x3d0 > [ 25.975047] RSP: 0018:ffff88008fed5c48 EFLAGS: 00010046 > [ 25.975052] RAX: 0000000000000096 RBX: 0000000000000292 RCX: 0000000000000000 > [ 25.975058] RDX: ffff880095281850 RSI: 0000000000000000 RDI: 0000000000000100 > [ 25.975063] RBP: ffff88008fed5c88 R08: 0000000000000000 R09: 0000000000000300 > [ 25.975069] R10: ffff880094981a00 R11: 0000000000000000 R12: ffff880095281850 > [ 25.975074] R13: 0000000000000000 R14: 0000000000000100 R15: 00000000000009c4 > [ 25.975081] FS: 00007f2f61707740(0000) GS:ffff88011fac0000(0000) > knlGS:0000000000000000 > [ 25.975088] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 25.975093] CR2: 0000000000000100 CR3: 000000009101f000 CR4: 00000000000407e0 > [ 25.975099] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [ 25.975104] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 ... > [ 25.975143] Call Trace: > [ 25.975151] [<ffffffff81077be5>] queue_work_on+0x45/0x50 > [ 25.975165] [<ffffffffa016e8ff>] hci_req_run+0xbf/0xf0 [bluetooth] > [ 25.975188] [<ffffffffa016ea06>] __hci_req_sync+0xd6/0x1c0 [bluetooth] > [ 25.975217] [<ffffffffa016fad5>] hci_dev_open+0x275/0x2e0 [bluetooth] > [ 25.975230] [<ffffffffa0182752>] hci_sock_ioctl+0x1f2/0x3f0 [bluetooth] > [ 25.975238] [<ffffffff815c6050>] sock_do_ioctl+0x30/0x70 > [ 25.975245] [<ffffffff815c75f9>] sock_ioctl+0x79/0x2f0 > [ 25.975254] [<ffffffff811a8046>] do_vfs_ioctl+0x96/0x560 > [ 25.975262] [<ffffffff811a85a1>] SyS_ioctl+0x91/0xb0 > [ 25.975271] [<ffffffff816d989d>] system_call_fastpath+0x1a/0x1f > [ 25.975276] Code: 89 e5 41 57 41 56 41 89 fe 41 55 49 89 f5 41 54 > 49 89 d4 53 48 83 ec 18 89 7d c8 9c 58 66 66 90 66 90 f6 c4 02 0f 85 > 56 02 00 00 <41> 8b 85 00 01 00 00 a9 00 00 01 00 0f 85 b0 02 00 00 48 > c7 c2 All code ======== 0: 89 e5 mov %esp,%ebp 2: 41 57 push %r15 4: 41 56 push %r14 6: 41 89 fe mov %edi,%r14d 9: 41 55 push %r13 b: 49 89 f5 mov %rsi,%r13 e: 41 54 push %r12 10: 49 89 d4 mov %rdx,%r12 13: 53 push %rbx 14: 48 83 ec 18 sub $0x18,%rsp 18: 89 7d c8 mov %edi,-0x38(%rbp) 1b: 9c pushfq 1c: 58 pop %rax 1d: 66 66 90 data32 xchg %ax,%ax 20: 66 90 xchg %ax,%ax 22: f6 c4 02 test $0x2,%ah 25: 0f 85 56 02 00 00 jne 0x281 2b:* 41 8b 85 00 01 00 00 mov 0x100(%r13),%eax <-- trapping instruction 32: a9 00 00 01 00 test $0x10000,%eax 37: 0f 85 b0 02 00 00 jne 0x2ed 3d: 48 rex.W 3e: c7 .byte 0xc7 3f: c2 .byte 0xc2 The second argument %rsi is zero, which got transferred to %r13 and then offset deref on it trapped. The second argument is @wq and the oopsing code is the wq->flags deref in the following if condition. /* if dying, only works from the same workqueue are allowed */ if (unlikely(wq->flags & __WQ_DRAINING) && WARN_ON_ONCE(!is_chained_work(wq))) return; So, umm, don't pass in NULL as @wq. :) -- tejun
