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.brost@intel.com Fixes: 531958f6f357 ("drm/i915/gt: Track timeline activeness in enter/exit") Cc: stable@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.Harrison@Intel.com
Also, free'd -> freed.
John.
*/- i915_syncmap_free(&timeline->sync);
- kfree(timeline); }