Description of problem: I've found this in log/messages this morning : Sep 16 23:25:24 gruyere kernel: ======================================================= Sep 16 23:25:24 gruyere kernel: [ INFO: possible circular locking dependency detected ] Sep 16 23:25:24 gruyere kernel: 2.6.17-1.2647.fc6 #1 Sep 16 23:25:24 gruyere kernel: ------------------------------------------------------- Sep 16 23:25:24 gruyere kernel: tvtime/3720 is trying to acquire lock: Sep 16 23:25:24 gruyere kernel: (&mm->mmap_sem){----}, at: [<ffffffff88308907>] videobuf_dma_init_user+0xd2/0x17a [ video_buf] Sep 16 23:25:24 gruyere kernel: Sep 16 23:25:24 gruyere kernel: but task is already holding lock: Sep 16 23:25:24 gruyere kernel: (&q->lock#2){--..}, at: [<ffffffff802666ef>] mutex_lock+0x2a/0x2e Sep 16 23:25:24 gruyere kernel: Sep 16 23:25:24 gruyere kernel: which lock already depends on the new lock. Sep 16 23:25:24 gruyere kernel: Sep 16 23:25:24 gruyere kernel: Sep 16 23:25:24 gruyere kernel: the existing dependency chain (in reverse order) is: Sep 16 23:25:24 gruyere kernel: Sep 16 23:25:24 gruyere kernel: -> #1 (&q->lock#2){--..}: Sep 16 23:25:24 gruyere kernel: [<ffffffff802a9742>] lock_acquire+0x4a/0x69 Sep 16 23:25:24 gruyere kernel: [<ffffffff80266548>] __mutex_lock_slowpath+0xe4/0x261 Sep 16 23:25:24 gruyere kernel: [<ffffffff802666ee>] mutex_lock+0x29/0x2e Sep 16 23:25:24 gruyere kernel: [<ffffffff883077ba>] videobuf_mmap_mapper+0x1b/0x23b [video_buf] Sep 16 23:25:24 gruyere kernel: [<ffffffff8831c0aa>] bttv_mmap+0x74/0x7a [bttv] Sep 16 23:25:24 gruyere kernel: [<ffffffff8020e495>] do_mmap_pgoff+0x4cf/0x7b7 Sep 16 23:25:24 gruyere kernel: [<ffffffff80225251>] sys_mmap+0x8e/0xca Sep 16 23:25:24 gruyere kernel: [<ffffffff8026084d>] system_call+0x7d/0x83 Sep 16 23:25:24 gruyere kernel: Sep 16 23:25:24 gruyere kernel: -> #0 (&mm->mmap_sem){----}: Sep 16 23:25:24 gruyere kernel: [<ffffffff802a9742>] lock_acquire+0x4a/0x69 Sep 16 23:25:24 gruyere kernel: [<ffffffff802a621f>] down_read+0x3d/0x4a Sep 16 23:25:24 gruyere kernel: [<ffffffff88308906>] videobuf_dma_init_user+0xd1/0x17a [video_buf] Sep 16 23:25:24 gruyere kernel: [<ffffffff88308c76>] videobuf_iolock+0x91/0xec [video_buf] Sep 16 23:25:25 gruyere kernel: [<ffffffff8831a159>] bttv_prepare_buffer+0x11e/0x16c [bttv] Sep 16 23:25:25 gruyere kernel: [<ffffffff8831a1d4>] buffer_prepare+0x2d/0x30 [bttv] Sep 16 23:25:25 gruyere kernel: [<ffffffff88309303>] videobuf_qbuf+0x247/0x2f4 [video_buf] Sep 16 23:25:25 gruyere kernel: [<ffffffff8831d59d>] bttv_do_ioctl+0x128c/0x1b2b [bttv] Sep 16 23:25:25 gruyere kernel: [<ffffffff8827aa78>] video_usercopy+0x1d0/0x2a9 [videodev] Sep 16 23:25:25 gruyere kernel: [<ffffffff8831a294>] bttv_ioctl+0x3b/0x41 [bttv] Sep 16 23:25:25 gruyere kernel: [<ffffffff80243c99>] do_ioctl+0x5d/0x77 Sep 16 23:25:25 gruyere kernel: [<ffffffff80232709>] vfs_ioctl+0x259/0x277 Sep 16 23:25:25 gruyere kernel: [<ffffffff8024ebe0>] sys_ioctl+0x5e/0x82 Sep 16 23:25:25 gruyere kernel: [<ffffffff8026084d>] system_call+0x7d/0x83 Sep 16 23:25:25 gruyere kernel: Sep 16 23:25:25 gruyere kernel: other info that might help us debug this: Sep 16 23:25:25 gruyere kernel: Sep 16 23:25:25 gruyere kernel: 1 lock held by tvtime/3720: Sep 16 23:25:25 gruyere kernel: #0: (&q->lock#2){--..}, at: [<ffffffff802666ef>] mutex_lock+0x2a/0x2e Sep 16 23:25:25 gruyere kernel: Sep 16 23:25:25 gruyere kernel: stack backtrace: Sep 16 23:25:25 gruyere kernel: Sep 16 23:25:25 gruyere kernel: Call Trace: Sep 16 23:25:25 gruyere kernel: [<ffffffff8026ebbd>] show_trace+0xae/0x336 Sep 16 23:25:25 gruyere kernel: [<ffffffff8026ee5a>] dump_stack+0x15/0x17 Sep 16 23:25:25 gruyere kernel: [<ffffffff802a7980>] print_circular_bug_tail+0x6c/0x77 Sep 16 23:25:25 gruyere kernel: [<ffffffff802a8f89>] __lock_acquire+0x84d/0xa64 Sep 16 23:25:25 gruyere kernel: [<ffffffff802a9743>] lock_acquire+0x4b/0x69 Sep 16 23:25:25 gruyere kernel: [<ffffffff802a6220>] down_read+0x3e/0x4a Sep 16 23:25:25 gruyere kernel: [<ffffffff88308907>] :video_buf:videobuf_dma_init_user+0xd2/0x17a Sep 16 23:25:25 gruyere kernel: [<ffffffff88308c77>] :video_buf:videobuf_iolock+0x92/0xec Sep 16 23:25:25 gruyere kernel: [<ffffffff8831a15a>] :bttv:bttv_prepare_buffer+0x11f/0x16c Sep 16 23:25:25 gruyere kernel: [<ffffffff8831a1d5>] :bttv:buffer_prepare+0x2e/0x30 Sep 16 23:25:25 gruyere kernel: [<ffffffff88309304>] :video_buf:videobuf_qbuf+0x248/0x2f4 Sep 16 23:25:25 gruyere kernel: [<ffffffff8831d59e>] :bttv:bttv_do_ioctl+0x128d/0x1b2b Sep 16 23:25:25 gruyere kernel: [<ffffffff8827aa79>] :videodev:video_usercopy+0x1d1/0x2a9 Sep 16 23:25:25 gruyere kernel: [<ffffffff8831a295>] :bttv:bttv_ioctl+0x3c/0x41 Sep 16 23:25:25 gruyere kernel: [<ffffffff80243c9a>] do_ioctl+0x5e/0x77 Sep 16 23:25:25 gruyere kernel: [<ffffffff8023270a>] vfs_ioctl+0x25a/0x277 Sep 16 23:25:25 gruyere kernel: [<ffffffff8024ebe1>] sys_ioctl+0x5f/0x82 Sep 16 23:25:25 gruyere kernel: [<ffffffff8026084e>] system_call+0x7e/0x83 Sep 16 23:25:25 gruyere kernel: DWARF2 unwinder stuck at system_call+0x7e/0x83 Sep 16 23:25:25 gruyere kernel: Leftover inexact backtrace: Version-Release number of selected component: 2.6.17-1.2647.fc6 system is fresh fc6 test3 updated to 16th/09 rawhide
Hello, I'm reviewing this bug as part of the kernel bug triage project, an attempt to isolate current bugs in the Fedora kernel. http://fedoraproject.org/wiki/KernelBugTriage I am CC'ing myself to this bug, however this version of Fedora is no longer maintained. Please attempt to reproduce this bug with a current version of Fedora (presently Fedora 8). If the bug no longer exists, please close the bug or I'll do so in a few days if there is no further information lodged. Thanks for using Fedora!
Closing per previous comment. If you can provide the requested information, please feel free to re-open this bug.