[Bug 109665] [CI][DRMTIP]igt at gem_mmap_gtt@forked-* - dmesg-warn - WARNING: possible recursive locking detected
bugzilla-daemon at freedesktop.org
bugzilla-daemon at freedesktop.org
Wed Feb 20 18:48:23 UTC 2019
https://bugs.freedesktop.org/show_bug.cgi?id=109665
Chris Wilson <chris at chris-wilson.co.uk> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|NEW |RESOLVED
--- Comment #5 from Chris Wilson <chris at chris-wilson.co.uk> ---
commit c1d1746f6d4b37518fe3dc4aba99db1f7a155bdb
Author: Chris Wilson <chris at chris-wilson.co.uk>
Date: Tue Feb 19 12:21:54 2019 +0000
drm/i915: Avoid reset lock in writing fence registers
The idea of taking the reset lock around writing the fence register was
to serialise the mmio write we also perform during the reset where those
registers get clobbered. However, the lock is overkill as write tearing
between reset and fence_update() is harmless; the final value of the
fence register is the same. A race between revoke_fences() and
fence_update() is also harmless at this point as on the fault path where
this is necessary, we acquire the reset lock to coordinate ourselves in
the upper layer.
The danger of acquiring the reset lock again in fence_update() is that
we may recurse from the shrinker along the i915_gem_fault() path.
<4> [125.739646] ============================================
<4> [125.739652] WARNING: possible recursive locking detected
<4> [125.739659] 5.0.0-rc6-ga6e4cbf00557-drmtip_223+ #1 Tainted: G U
<4> [125.739666] --------------------------------------------
<4> [125.739672] gem_mmap_gtt/1017 is trying to acquire lock:
<4> [125.739679] 00000000a730190a
(&dev_priv->gpu_error.reset_backoff_srcu){+.+.}, at:
i915_reset_trylock+0x0/0x310 [i915]
<4> [125.739848]
but task is already holding lock:
<4> [125.739854] 00000000a730190a
(&dev_priv->gpu_error.reset_backoff_srcu){+.+.}, at:
i915_reset_trylock+0x192/0x310 [i915]
<4> [125.739918]
other info that might help us debug this:
<4> [125.739925] Possible unsafe locking scenario:
<4> [125.739930] CPU0
<4> [125.739934] ----
<4> [125.739937] lock(&dev_priv->gpu_error.reset_backoff_srcu);
<4> [125.739944] lock(&dev_priv->gpu_error.reset_backoff_srcu);
<4> [125.739950]
*** DEADLOCK ***
<4> [125.739958] May be due to missing lock nesting notation
<4> [125.739966] 5 locks held by gem_mmap_gtt/1017:
<4> [125.739972] #0: 00000000471f682c (&mm->mmap_sem){++++}, at:
__do_page_fault+0x133/0x500
<4> [125.739987] #1: 0000000026542685 (&dev->struct_mutex){+.+.}, at:
i915_gem_fault+0x1f6/0x860 [i915]
<4> [125.740061] #2: 00000000a730190a
(&dev_priv->gpu_error.reset_backoff_srcu){+.+.}, at:
i915_reset_trylock+0x192/0x310 [i915]
<4> [125.740126] #3: 00000000c828eb4f (fs_reclaim){+.+.}, at:
fs_reclaim_acquire.part.25+0x0/0x30
<4> [125.740140] #4: 000000002d360d65 (shrinker_rwsem){++++}, at:
shrink_slab+0x1cb/0x2c0
<4> [125.740151]
stack backtrace:
<4> [125.740159] CPU: 1 PID: 1017 Comm: gem_mmap_gtt Tainted: G U
5.0.0-rc6-ga6e4cbf00557-drmtip_223+ #1
<4> [125.740170] Hardware name: Dell Inc. OptiPlex 745
/0GW726, BIOS 2.3.1 05/21/2007
<4> [125.740180] Call Trace:
<4> [125.740189] dump_stack+0x67/0x9b
<4> [125.740199] __lock_acquire+0xc75/0x1b00
<4> [125.740209] ? arch_tlb_finish_mmu+0x2a/0xa0
<4> [125.740216] ? tlb_finish_mmu+0x1a/0x30
<4> [125.740222] ? zap_page_range_single+0xe2/0x130
<4> [125.740230] ? lock_acquire+0xa6/0x1c0
<4> [125.740237] lock_acquire+0xa6/0x1c0
<4> [125.740296] ? i915_clear_error_registers+0x280/0x280 [i915]
<4> [125.740357] i915_reset_trylock+0x44/0x310 [i915]
<4> [125.740417] ? i915_clear_error_registers+0x280/0x280 [i915]
<4> [125.740426] ? lockdep_hardirqs_on+0xe0/0x1b0
<4> [125.740434] ? _raw_spin_unlock_irqrestore+0x39/0x60
<4> [125.740499] fence_update+0x218/0x470 [i915]
<4> [125.740571] i915_vma_unbind+0xa6/0x550 [i915]
<4> [125.740640] i915_gem_object_unbind+0xfa/0x190 [i915]
<4> [125.740711] i915_gem_shrink+0x2dc/0x590 [i915]
<4> [125.740722] ? ___preempt_schedule+0x16/0x18
<4> [125.740792] ? i915_gem_shrinker_scan+0xc9/0x130 [i915]
<4> [125.740861] i915_gem_shrinker_scan+0xc9/0x130 [i915]
<4> [125.740870] do_shrink_slab+0x143/0x3f0
<4> [125.740878] shrink_slab+0x228/0x2c0
<4> [125.740886] shrink_node+0x167/0x450
<4> [125.740894] do_try_to_free_pages+0xc4/0x340
<4> [125.740902] try_to_free_pages+0xdc/0x2e0
<4> [125.740911] __alloc_pages_nodemask+0x662/0x1110
<4> [125.740921] ? reacquire_held_locks+0xb5/0x1b0
<4> [125.740928] ? reacquire_held_locks+0xb5/0x1b0
<4> [125.740986] ? i915_reset_trylock+0x192/0x310 [i915]
<4> [125.741045] ? i915_memcpy_init_early+0x30/0x30 [i915]
<4> [125.741054] pte_alloc_one+0x12/0x70
<4> [125.741060] __pte_alloc+0x11/0xf0
<4> [125.741067] apply_to_page_range+0x37e/0x440
<4> [125.741127] remap_io_mapping+0x6c/0x100 [i915]
<4> [125.741196] i915_gem_fault+0x5a9/0x860 [i915]
<4> [125.741204] ? ptlock_alloc+0x15/0x30
<4> [125.741212] __do_fault+0x2c/0xb0
<4> [125.741218] __handle_mm_fault+0x8ee/0xfa0
<4> [125.741227] handle_mm_fault+0x196/0x3a0
<4> [125.741235] __do_page_fault+0x246/0x500
<4> [125.741243] ? page_fault+0x8/0x30
<4> [125.741250] page_fault+0x1e/0x30
<4> [125.741256] RIP: 0033:0x55d0cc456e12
<4> [125.741264] Code: b0 df ff ff 89 c2 8b 85 70 df ff ff 01 c2 8b 85 70
df ff ff 48 98 48 8d 0c 85 00 00 00 00 48 8b 85 e0 df ff ff 48 01 c8 f7 d2 <89>
10 83 85 70 df ff ff 01 81 bd 70 df ff ff ff 03 00 00 7e be 48
<4> [125.741280] RSP: 002b:00007ffc1bab7ab0 EFLAGS: 00010206
<4> [125.741287] RAX: 00007fc787cb6000 RBX: 0000000000000000 RCX:
0000000000000000
<4> [125.741295] RDX: 00000000ffffffff RSI: 0000000000005401 RDI:
0000000000000002
<4> [125.741303] RBP: 00007ffc1bab9b70 R08: 00007ffc1bab7920 R09:
000000000000001b
<4> [125.741310] R10: 7165722074736554 R11: 0000000000000246 R12:
000055d0cc454a80
<4> [125.741318] R13: 00007ffc1bab9f60 R14: 0000000000000000 R15:
0000000000000000
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109665
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>
Link:
https://patchwork.freedesktop.org/patch/msgid/20190219122215.8941-4-chris@chris-wilson.co.uk
--
You are receiving this mail because:
You are on the CC list for the bug.
You are the QA Contact for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/intel-gfx-bugs/attachments/20190220/a9b6d012/attachment-0001.html>
More information about the intel-gfx-bugs
mailing list