fb+drm: possible circular locking dependency detected
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From: Clemens Ladisch on 11 May 2010 07:10 With radeon KMS, after using a program accessing the framebuffer, I started X and got this: ======================================================= [ INFO: possible circular locking dependency detected ] 2.6.34-rc6 #117 ------------------------------------------------------- X/1846 is trying to acquire lock: (&mm->mmap_sem){++++++}, at: [<ffffffff8108d36f>] might_fault+0x57/0xa4 but task is already holding lock: (&dev->mode_config.mutex){+.+.+.}, at: [<ffffffff8125f258>] drm_mode_getresources+0x33/0x54d which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&dev->mode_config.mutex){+.+.+.}: [<ffffffff8105d185>] __lock_acquire+0x1408/0x1747 [<ffffffff8105d51e>] lock_acquire+0x5a/0x71 [<ffffffff8143284a>] mutex_lock_nested+0x58/0x2b1 [<ffffffff8124e1d8>] drm_fb_helper_set_par+0x9c/0xf2 [<ffffffff811de45f>] fb_set_var+0x1de/0x2d9 [<ffffffff811de694>] do_fb_ioctl+0x13a/0x46e [<ffffffff811dede2>] fb_ioctl+0x21/0x23 [<ffffffff810b3c80>] vfs_ioctl+0x2a/0x9e [<ffffffff810b4235>] do_vfs_ioctl+0x4b7/0x4f4 [<ffffffff810b42b4>] sys_ioctl+0x42/0x65 [<ffffffff81001feb>] system_call_fastpath+0x16/0x1b -> #1 (&fb_info->lock){+.+.+.}: [<ffffffff8105d185>] __lock_acquire+0x1408/0x1747 [<ffffffff8105d51e>] lock_acquire+0x5a/0x71 [<ffffffff8143284a>] mutex_lock_nested+0x58/0x2b1 [<ffffffff811dd60a>] fb_release+0x1c/0x54 [<ffffffff810a8585>] __fput+0x120/0x1e3 [<ffffffff810a8660>] fput+0x18/0x1a [<ffffffff81093287>] remove_vma+0x51/0x76 [<ffffffff81094245>] do_munmap+0x30a/0x32e [<ffffffff810942a4>] sys_munmap+0x3b/0x54 [<ffffffff81001feb>] system_call_fastpath+0x16/0x1b -> #0 (&mm->mmap_sem){++++++}: [<ffffffff8105ceaa>] __lock_acquire+0x112d/0x1747 [<ffffffff8105d51e>] lock_acquire+0x5a/0x71 [<ffffffff8108d39c>] might_fault+0x84/0xa4 [<ffffffff8125f4a5>] drm_mode_getresources+0x280/0x54d [<ffffffff8125519f>] drm_ioctl+0x255/0x34b [<ffffffff810b3c80>] vfs_ioctl+0x2a/0x9e [<ffffffff810b4235>] do_vfs_ioctl+0x4b7/0x4f4 [<ffffffff810b42b4>] sys_ioctl+0x42/0x65 [<ffffffff81001feb>] system_call_fastpath+0x16/0x1b other info that might help us debug this: 1 lock held by X/1846: #0: (&dev->mode_config.mutex){+.+.+.}, at: [<ffffffff8125f258>] drm_mode_getresources+0x33/0x54d stack backtrace: Pid: 1846, comm: X Not tainted 2.6.34-rc6 #117 Call Trace: [<ffffffff8105b82f>] print_circular_bug+0xb3/0xc2 [<ffffffff8105ceaa>] __lock_acquire+0x112d/0x1747 [<ffffffff8105aef4>] ? mark_held_locks+0x4d/0x6b [<ffffffff81432a88>] ? mutex_lock_nested+0x296/0x2b1 [<ffffffff8105d51e>] lock_acquire+0x5a/0x71 [<ffffffff8108d36f>] ? might_fault+0x57/0xa4 [<ffffffff8108d39c>] might_fault+0x84/0xa4 [<ffffffff8108d36f>] ? might_fault+0x57/0xa4 [<ffffffff8125f4a5>] drm_mode_getresources+0x280/0x54d [<ffffffff8125519f>] drm_ioctl+0x255/0x34b [<ffffffff8125f225>] ? drm_mode_getresources+0x0/0x54d [<ffffffff8104f629>] ? up_read+0x1e/0x35 [<ffffffff810b3c80>] vfs_ioctl+0x2a/0x9e [<ffffffff810b4235>] do_vfs_ioctl+0x4b7/0x4f4 [<ffffffff8100201c>] ? sysret_check+0x27/0x62 [<ffffffff810b42b4>] sys_ioctl+0x42/0x65 [<ffffffff81001feb>] system_call_fastpath+0x16/0x1b -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |