On 8/6/2021 11:29, Matthew Brost wrote:
On Fri, Aug 06, 2021 at 11:23:06AM -0700, John Harrison wrote:
On 7/30/2021 12:53, Matthew Brost wrote:
A small race exists between intel_gt_retire_requests_timeout and
intel_timeline_exit which could result in the syncmap not getting
free'd. Rather than work to hard to seal this race, simply cleanup the
free'd -> freed
Sure.
syncmap on fini.
unreferenced object 0xffff88813bc53b18 (size 96):
comm "gem_close_race", pid 5410, jiffies 4294917818 (age 1105.600s)
hex dump (first 32 bytes):
01 00 00 00 00 00 00 00 00 00 00 00 0a 00 00 00 ................
00 00 00 00 00 00 00 00 6b 6b 6b 6b 06 00 00 00 ........kkkk....
backtrace:
[<00000000120b863a>] __sync_alloc_leaf+0x1e/0x40 [i915]
[<00000000042f6959>] __sync_set+0x1bb/0x240 [i915]
[<0000000090f0e90f>] i915_request_await_dma_fence+0x1c7/0x400 [i915]
[<0000000056a48219>] i915_request_await_object+0x222/0x360 [i915]
[<00000000aaac4ee3>] i915_gem_do_execbuffer+0x1bd0/0x2250 [i915]
[<000000003c9d830f>] i915_gem_execbuffer2_ioctl+0x405/0xce0 [i915]
[<00000000fd7a8e68>] drm_ioctl_kernel+0xb0/0xf0 [drm]
[<00000000e721ee87>] drm_ioctl+0x305/0x3c0 [drm]
[<000000008b0d8986>] __x64_sys_ioctl+0x71/0xb0
[<0000000076c362a4>] do_syscall_64+0x33/0x80
[<00000000eb7a4831>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
Signed-off-by: Matthew Brost <matthew.br...@intel.com>
Fixes: 531958f6f357 ("drm/i915/gt: Track timeline activeness in enter/exit")
Cc: <sta...@vger.kernel.org>
---
drivers/gpu/drm/i915/gt/intel_timeline.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_timeline.c
b/drivers/gpu/drm/i915/gt/intel_timeline.c
index c4a126c8caef..1257f4f11e66 100644
--- a/drivers/gpu/drm/i915/gt/intel_timeline.c
+++ b/drivers/gpu/drm/i915/gt/intel_timeline.c
@@ -127,6 +127,15 @@ static void intel_timeline_fini(struct rcu_head *rcu)
i915_vma_put(timeline->hwsp_ggtt);
i915_active_fini(&timeline->active);
+
+ /*
+ * A small race exists between intel_gt_retire_requests_timeout and
+ * intel_timeline_exit which could result in the syncmap not getting
+ * free'd. Rather than work to hard to seal this race, simply cleanup
+ * the syncmap on fini.
What is the race? I'm going round in circles just trying to work out how
intel_gt_retire_requests_timeout is supposed to get to intel_timeline_exit
in the first place.
intel_gt_retire_requests_timeout increments tl->active_count, active_count == 2
intel_timeline_exit is called, returns on atomic_add_unless, active_count == 1
intel_gt_retire_requests_timeout decrements tl->active_count, active_count == 0
i915_syncmap_free is never called, memory leak
Matt
Okay. Think I follow it now.
Seems like the syncmap free should have been in timeline_fini instead of
timeline_exit in the first place?
Reviewed-by: John Harrison <john.c.harri...@intel.com>
Also, free'd -> freed.
John.
+ */
+ i915_syncmap_free(&timeline->sync);
+
kfree(timeline);
}
