From 60900add85965bf4aba8d945f4766cfc7f81e8a2 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 9 Mar 2020 13:27:26 +0000 Subject: [PATCH] drm/i915: Mark racy read of intel_engine_cs.saturated [ 3783.276728] BUG: KCSAN: data-race in __i915_request_submit [i915] / i915_request_await_dma_fence [i915] [ 3783.276766] [ 3783.276787] write to 0xffff8881f1bc60a0 of 1 bytes by interrupt on cpu 2: [ 3783.277187] __i915_request_submit+0x47e/0x4a0 [i915] [ 3783.277580] __execlists_submission_tasklet+0x997/0x2780 [i915] [ 3783.277973] execlists_submission_tasklet+0xd3/0x170 [i915] [ 3783.278006] tasklet_action_common.isra.0+0x42/0xa0 [ 3783.278035] __do_softirq+0xd7/0x2cd [ 3783.278063] irq_exit+0xbe/0xe0 [ 3783.278089] do_IRQ+0x51/0x100 [ 3783.278114] ret_from_intr+0x0/0x1c [ 3783.278140] finish_task_switch+0x72/0x260 [ 3783.278170] __schedule+0x1e5/0x510 [ 3783.278198] schedule+0x45/0xb0 [ 3783.278226] smpboot_thread_fn+0x23e/0x300 [ 3783.278256] kthread+0x19a/0x1e0 [ 3783.278283] ret_from_fork+0x1f/0x30 [ 3783.278305] [ 3783.278327] read to 0xffff8881f1bc60a0 of 1 bytes by task 19440 on cpu 3: [ 3783.278724] i915_request_await_dma_fence+0x2a6/0x530 [i915] [ 3783.279130] i915_request_await_object+0x2fe/0x470 [i915] [ 3783.279524] i915_gem_do_execbuffer+0x45dc/0x4c20 [i915] [ 3783.279908] i915_gem_execbuffer2_ioctl+0x2c3/0x580 [i915] [ 3783.279940] drm_ioctl_kernel+0xe4/0x120 [ 3783.279968] drm_ioctl+0x297/0x4c7 [ 3783.279996] ksys_ioctl+0x89/0xb0 [ 3783.280021] __x64_sys_ioctl+0x42/0x60 [ 3783.280047] do_syscall_64+0x6e/0x2c0 [ 3783.280074] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Signed-off-by: Chris Wilson Reviewed-by: Mika Kuoppala Link: https://patchwork.freedesktop.org/patch/msgid/20200309132726.28358-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_request.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index 5de3989b6c4f..04b52bf347bf 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -907,7 +907,7 @@ already_busywaiting(struct i915_request *rq) * * See the are-we-too-late? check in __i915_request_submit(). */ - return rq->sched.semaphores | rq->engine->saturated; + return rq->sched.semaphores | READ_ONCE(rq->engine->saturated); } static int -- 2.30.2