In commit 142639a52a01 ("drm/msm/a6xx: fix crashstate capture for A650") we changed a6xx_get_gmu_registers() to read 3 sets of registers. Unfortunately, we didn't change the memory allocation for the array. That leads to a KASAN warning (this was on the chromeos-5.4 kernel, which has the problematic commit backported to it):
BUG: KASAN: slab-out-of-bounds in _a6xx_get_gmu_registers+0x144/0x430 Write of size 8 at addr ffffff80c89432b0 by task A618-worker/209 CPU: 5 PID: 209 Comm: A618-worker Tainted: G W 5.4.156-lockdep #22 Hardware name: Google Lazor Limozeen without Touchscreen (rev5 - rev8) (DT) Call trace: dump_backtrace+0x0/0x248 show_stack+0x20/0x2c dump_stack+0x128/0x1ec print_address_description+0x88/0x4a0 __kasan_report+0xfc/0x120 kasan_report+0x10/0x18 __asan_report_store8_noabort+0x1c/0x24 _a6xx_get_gmu_registers+0x144/0x430 a6xx_gpu_state_get+0x330/0x25d4 msm_gpu_crashstate_capture+0xa0/0x84c recover_worker+0x328/0x838 kthread_worker_fn+0x32c/0x574 kthread+0x2dc/0x39c ret_from_fork+0x10/0x18
Allocated by task 209: __kasan_kmalloc+0xfc/0x1c4 kasan_kmalloc+0xc/0x14 kmem_cache_alloc_trace+0x1f0/0x2a0 a6xx_gpu_state_get+0x164/0x25d4 msm_gpu_crashstate_capture+0xa0/0x84c recover_worker+0x328/0x838 kthread_worker_fn+0x32c/0x574 kthread+0x2dc/0x39c ret_from_fork+0x10/0x18
Fixes: 142639a52a01 ("drm/msm/a6xx: fix crashstate capture for A650") Signed-off-by: Douglas Anderson dianders@chromium.org --- I don't actually know how to trigger a GPU crash. I just happened to trigger one by getting "lucky" and hitting a timeout after being in kdb. Thus this is just compile tested. However, it looks pretty sane to me. ;-)
drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c index 7501849ed15d..6e90209cd543 100644 --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c @@ -777,12 +777,12 @@ static void a6xx_get_gmu_registers(struct msm_gpu *gpu, struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
a6xx_state->gmu_registers = state_kcalloc(a6xx_state, - 2, sizeof(*a6xx_state->gmu_registers)); + 3, sizeof(*a6xx_state->gmu_registers));
if (!a6xx_state->gmu_registers) return;
- a6xx_state->nr_gmu_registers = 2; + a6xx_state->nr_gmu_registers = 3;
/* Get the CX GMU registers from AHB */ _a6xx_get_gmu_registers(gpu, a6xx_state, &a6xx_gmu_reglist[0],