From 43c048b2fa01321fec9bad5afb99fc741f6744b7 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Mon, 9 Mar 2020 11:36:23 +0000
Subject: drm/i915/gt: Mark up intel_rps.active for racy reads
Git-commit: ff34527103d2bcd5d98387bce268a8852bb565c5
Patch-mainline: v5.7-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322
We read the current state of intel_rps.active outside of the lock, so
mark up the racy access.
[ 525.037073] BUG: KCSAN: data-race in intel_rps_boost [i915] / intel_rps_park [i915]
[ 525.037091]
[ 525.037103] write to 0xffff8881f145efa1 of 1 bytes by task 192 on cpu 2:
[ 525.037331] intel_rps_park+0x72/0x230 [i915]
[ 525.037552] __gt_park+0x61/0xa0 [i915]
[ 525.037771] ____intel_wakeref_put_last+0x42/0x90 [i915]
[ 525.037991] __intel_wakeref_put_work+0xd3/0xf0 [i915]
[ 525.038008] process_one_work+0x3b1/0x690
[ 525.038022] worker_thread+0x80/0x670
[ 525.038037] kthread+0x19a/0x1e0
[ 525.038051] ret_from_fork+0x1f/0x30
[ 525.038062]
[ 525.038074] read to 0xffff8881f145efa1 of 1 bytes by task 733 on cpu 3:
[ 525.038304] intel_rps_boost+0x67/0x1f0 [i915]
[ 525.038535] i915_request_wait+0x562/0x5d0 [i915]
[ 525.038764] i915_gem_object_wait_fence+0x81/0xa0 [i915]
[ 525.038994] i915_gem_object_wait_reservation+0x489/0x520 [i915]
[ 525.039224] i915_gem_wait_ioctl+0x167/0x2b0 [i915]
[ 525.039241] drm_ioctl_kernel+0xe4/0x120
[ 525.039255] drm_ioctl+0x297/0x4c7
[ 525.039269] ksys_ioctl+0x89/0xb0
[ 525.039282] __x64_sys_ioctl+0x42/0x60
[ 525.039296] do_syscall_64+0x6e/0x2c0
[ 525.039311] entry_SYSCALL_64_after_hwframe+0x44/0xa9
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200309113623.24208-1-chris@chris-wilson.co.uk
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/gt/intel_rps.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c b/drivers/gpu/drm/i915/gt/intel_rps.c
index c22c59ba88f2..506738dede16 100644
--- a/drivers/gpu/drm/i915/gt/intel_rps.c
+++ b/drivers/gpu/drm/i915/gt/intel_rps.c
@@ -727,6 +727,7 @@ void intel_rps_unpark(struct intel_rps *rps)
freq = max(rps->cur_freq, rps->efficient_freq),
freq = clamp(freq, rps->min_freq_softlimit, rps->max_freq_softlimit);
intel_rps_set(rps, freq);
+
rps->last_adj = 0;
mutex_unlock(&rps->lock);
--
2.28.0