Hi,
I noticed this while testing the displayport output attached
to the nvidia GPU on a Thinkpad P50 while the intel GPU
was driving the LCD panel (and was the primary GPU according
to Xorg). This was while logging into gnome-3 with Xorg-1.19-rc2,
from gdm (also running on top of Xorg-1.19-rc2).
[ 23.892394] ======================================================
[ 23.892395] [ INFO: possible circular locking dependency detected ]
[ 23.892397] 4.9.0-rc1+ #51 Not tainted
[ 23.892398] -------------------------------------------------------
[ 23.892399] Xorg/1252 is trying to acquire lock:
[ 23.892400] (
[ 23.892401] reservation_ww_class_mutex
[ 23.892402] ){+.+.+.}
[ 23.892403] , at:
[ 23.892429] [<ffffffffc042bac4>]
i915_gem_do_execbuffer.isra.46+0x1654/0x1c10 [i915]
[ 23.892430]
but task is already holding lock:
[ 23.892431] (
[ 23.892432] &dev->struct_mutex
[ 23.892433] ){+.+.+.}
[ 23.892433] , at:
[ 23.892447] [<ffffffffc0436be3>] i915_mutex_lock_interruptible+0x23/0x40
[i915]
[ 23.892448]
which lock already depends on the new lock.
[ 23.892450]
the existing dependency chain (in reverse order) is:
[ 23.892451]
-> #1
[ 23.892451] (
[ 23.892452] &dev->struct_mutex
[ 23.892453] ){+.+.+.}
[ 23.892453] :
[ 23.892454]
[ 23.892458] [<ffffffffaf1127e6>] lock_acquire+0xf6/0x1f0
[ 23.892459]
[ 23.892470] [<ffffffffc0228ba5>]
drm_gem_object_unreference_unlocked+0x45/0xe0 [drm]
[ 23.892471]
[ 23.892502] [<ffffffffc06198d5>] validate_fini_no_ticket+0x85/0xf0 [nouveau]
[ 23.892503]
[ 23.892525] [<ffffffffc061abb2>] nouveau_gem_ioctl_pushbuf+0x312/0x10c0
[nouveau]
[ 23.892526]
[ 23.892533] [<ffffffffc0229f2a>] drm_ioctl+0x37a/0x4e0 [drm]
[ 23.892534]
[ 23.892556] [<ffffffffc0611994>] nouveau_drm_ioctl+0x74/0xc0 [nouveau]
[ 23.892557]
[ 23.892559] [<ffffffffaf2beab3>] do_vfs_ioctl+0xa3/0x6f0
[ 23.892560]
[ 23.892562] [<ffffffffaf2bf179>] SyS_ioctl+0x79/0x90
[ 23.892562]
[ 23.892565] [<ffffffffaf90a941>] entry_SYSCALL_64_fastpath+0x1f/0xc2
[ 23.892566]
-> #0
[ 23.892567] (
[ 23.892567] reservation_ww_class_mutex
[ 23.892568] ){+.+.+.}
[ 23.892569] :
[ 23.892569]
[ 23.892571] [<ffffffffaf1121ee>] __lock_acquire+0x10fe/0x1290
[ 23.892572]
[ 23.892574] [<ffffffffaf1127e6>] lock_acquire+0xf6/0x1f0
[ 23.892574]
[ 23.892576] [<ffffffffaf905e96>] mutex_lock_nested+0x86/0x3f0
[ 23.892577]
[ 23.892592] [<ffffffffc042bac4>]
i915_gem_do_execbuffer.isra.46+0x1654/0x1c10 [i915]
[ 23.892592]
[ 23.892605] [<ffffffffc042c4bf>] i915_gem_execbuffer2+0xcf/0x260 [i915]
[ 23.892606]
[ 23.892613] [<ffffffffc0229f2a>] drm_ioctl+0x37a/0x4e0 [drm]
[ 23.892614]
[ 23.892616] [<ffffffffaf2beab3>] do_vfs_ioctl+0xa3/0x6f0
[ 23.892617]
[ 23.892619] [<ffffffffaf2bf179>] SyS_ioctl+0x79/0x90
[ 23.892619]
[ 23.892621] [<ffffffffaf90a941>] entry_SYSCALL_64_fastpath+0x1f/0xc2
[ 23.892622]
other info that might help us debug this:
[ 23.892624] Possible unsafe locking scenario:
[ 23.892626] CPU0 CPU1
[ 23.892627] ---- ----
[ 23.892628] lock(
[ 23.892629] &dev->struct_mutex
[ 23.892630] );
[ 23.892632] lock(
[ 23.892633] reservation_ww_class_mutex
[ 23.892634] );
[ 23.892634] lock(
[ 23.892635] &dev->struct_mutex
[ 23.892636] );
[ 23.892636] lock(
[ 23.892637] reservation_ww_class_mutex
[ 23.892638] );
[ 23.892639]
*** DEADLOCK ***
[ 23.892641] 1 lock held by Xorg/1252:
[ 23.892641] #0:
[ 23.892642] (
[ 23.892643] &dev->struct_mutex
[ 23.892643] ){+.+.+.}
[ 23.892644] , at:
[ 23.892658] [<ffffffffc0436be3>] i915_mutex_lock_interruptible+0x23/0x40
[i915]
[ 23.892659]
stack backtrace:
[ 23.892661] CPU: 0 PID: 1252 Comm: Xorg Not tainted 4.9.0-rc1+ #51
[ 23.892662] Hardware name: LENOVO 20EQS3R300/20EQS3R300, BIOS N1EET57W (1.30
) 08/03/2016
[ 23.892663] ffff9e02032c79d0 ffffffffaf46b523 ffffffffb0bd6d30
ffffffffb0bd6d30
[ 23.892667] ffff9e02032c7a10 ffffffffaf10f85e 00000000af1f8000
ffff9262af1f8ce0
[ 23.892669] ffff9262af1f8000 ffff9262af1f8ca8 0000000000000001
0000000000000000
[ 23.892672] Call Trace:
[ 23.892675] [<ffffffffaf46b523>] dump_stack+0x86/0xc3
[ 23.892677] [<ffffffffaf10f85e>] print_circular_bug+0x1be/0x210
[ 23.892679] [<ffffffffaf1121ee>] __lock_acquire+0x10fe/0x1290
[ 23.892681] [<ffffffffaf626fe1>] ?
reservation_object_get_fences_rcu+0x201/0x4d0
[ 23.892683] [<ffffffffaf1127e6>] lock_acquire+0xf6/0x1f0
[ 23.892696] [<ffffffffc042bac4>] ?
i915_gem_do_execbuffer.isra.46+0x1654/0x1c10 [i915]
[ 23.892698] [<ffffffffaf905e96>] mutex_lock_nested+0x86/0x3f0
[ 23.892711] [<ffffffffc042bac4>] ?
i915_gem_do_execbuffer.isra.46+0x1654/0x1c10 [i915]
[ 23.892722] [<ffffffffc042bac4>] ?
i915_gem_do_execbuffer.isra.46+0x1654/0x1c10 [i915]
[ 23.892734] [<ffffffffc042a3b2>] ? i915_vma_move_to_active+0x152/0x210
[i915]
[ 23.892745] [<ffffffffc042bac4>]
i915_gem_do_execbuffer.isra.46+0x1654/0x1c10 [i915]
[ 23.892752] [<ffffffffc0228b6a>] ?
drm_gem_object_unreference_unlocked+0xa/0xe0 [drm]
[ 23.892755] [<ffffffffaf23b993>] ? __might_fault+0x43/0xa0
[ 23.892767] [<ffffffffc042c4bf>] i915_gem_execbuffer2+0xcf/0x260 [i915]
[ 23.892774] [<ffffffffc0229f2a>] drm_ioctl+0x37a/0x4e0 [drm]
[ 23.892785] [<ffffffffc042c3f0>] ? i915_gem_execbuffer+0x370/0x370 [i915]
[ 23.892788] [<ffffffffaf2beab3>] do_vfs_ioctl+0xa3/0x6f0
[ 23.892790] [<ffffffffaf2cc3f5>] ? __fget+0x5/0x200
[ 23.892792] [<ffffffffaf2bf179>] SyS_ioctl+0x79/0x90
[ 23.892795] [<ffffffffaf90a941>] entry_SYSCALL_64_fastpath+0x1f/0xc2
I'm attach the entire dmesg in case it is useful. Note I cannot reproduce this
at
will I'm afraid.
Regards,
Hans
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