We need ww mutexes and need to rewrite i915 a bit fo fix this all. I.e. known issue. As long as your userspace isn't nasty nothing bad will ever happen though. -Daniel
On Mon, Oct 13, 2014 at 08:40:33PM +0200, Marcin Ślusarz wrote:
============================================= [ INFO: possible recursive locking detected ] 3.17.0 #50 Not tainted
Xorg/1170 is trying to acquire lock: (&dev->struct_mutex){+.+.+.}, at: [<ffffffffa010ae93>] i915_gem_unmap_dma_buf+0x33/0xc0 [i915]
but task is already holding lock: (&dev->struct_mutex){+.+.+.}, at: [<ffffffffa001cd1a>] drm_gem_object_handle_unreference_unlocked+0xca/0x120 [drm]
other info that might help us debug this: Possible unsafe locking scenario:
CPU0 ----lock(&dev->struct_mutex); lock(&dev->struct_mutex);
*** DEADLOCK ***
May be due to missing lock nesting notation
1 lock held by Xorg/1170: #0: (&dev->struct_mutex){+.+.+.}, at: [<ffffffffa001cd1a>] drm_gem_object_handle_unreference_unlocked+0xca/0x120 [drm]
stack backtrace: CPU: 1 PID: 1170 Comm: Xorg Not tainted 3.17.0 #50 Hardware name: Dell Inc. Inspiron 7720/04M3YM, BIOS A07 08/16/2012 ffffffff82606b80 ffff880136e27b00 ffffffff81707891 ffffffff82606b80 ffff880136e27bb8 ffffffff810e0e4f ffffffff00000000 000202000000c795 0000000000000001 0000000000000000 00000000004ec276 0000000000000300 Call Trace: [<ffffffff81707891>] dump_stack+0x4e/0x7a [<ffffffff810e0e4f>] __lock_acquire+0x194f/0x19e0 [<ffffffff810e1631>] lock_acquire+0x91/0x120 [<ffffffffa010ae93>] ? i915_gem_unmap_dma_buf+0x33/0xc0 [i915] [<ffffffffa010ae93>] ? i915_gem_unmap_dma_buf+0x33/0xc0 [i915] [<ffffffff8170c014>] mutex_lock_nested+0x54/0x3d0 [<ffffffffa010ae93>] ? i915_gem_unmap_dma_buf+0x33/0xc0 [i915] [<ffffffff810df03a>] ? mark_held_locks+0x6a/0x90 [<ffffffffa010ae93>] i915_gem_unmap_dma_buf+0x33/0xc0 [i915] [<ffffffff814c3032>] dma_buf_unmap_attachment+0x22/0x40 [<ffffffffa0034e42>] drm_prime_gem_destroy+0x22/0x40 [drm] [<ffffffffa0299b5b>] nouveau_gem_object_del+0x3b/0x60 [nouveau] [<ffffffffa001c7b7>] drm_gem_object_free+0x27/0x30 [drm] [<ffffffffa001cd34>] drm_gem_object_handle_unreference_unlocked+0xe4/0x120 [drm] [<ffffffffa001ce2a>] drm_gem_handle_delete+0xba/0x110 [drm] [<ffffffffa001d495>] drm_gem_close_ioctl+0x25/0x30 [drm] [<ffffffffa001df0c>] drm_ioctl+0x1ec/0x660 [drm] [<ffffffff8148e4b2>] ? __pm_runtime_resume+0x32/0x60 [<ffffffff817102fd>] ? _raw_spin_unlock_irqrestore+0x5d/0x70 [<ffffffff810df15d>] ? trace_hardirqs_on_caller+0xfd/0x1c0 [<ffffffff810df22d>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff817102e2>] ? _raw_spin_unlock_irqrestore+0x42/0x70 [<ffffffffa0290bd4>] nouveau_drm_ioctl+0x54/0xc0 [nouveau] [<ffffffff812072a0>] do_vfs_ioctl+0x300/0x520 [<ffffffff81211fad>] ? __fget+0xad/0xe0 [<ffffffff81211f05>] ? __fget+0x5/0xe0 [<ffffffff81207541>] SyS_ioctl+0x81/0xa0 [<ffffffff81710ed6>] system_call_fastpath+0x1a/0x1f _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx