[PATCH] drm/amdgpu: Avoid integer overflow in amdgpu_device_suspend_display_audio

From: Nathan Chancellor <natechancellor@gmail.com>
To: "Alex Deucher" <alexander.deucher@amd.com>,
	"Christian König" <christian.koenig@amd.com>,
	"David (ChunMing) Zhou" <David1.Zhou@amd.com>
Cc: amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
	linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com,
	Nathan Chancellor <natechancellor@gmail.com>
Subject: [PATCH] drm/amdgpu: Avoid integer overflow in amdgpu_device_suspend_display_audio
Date: Fri,  1 May 2020 20:11:41 -0700	[thread overview]
Message-ID: <20200502031141.2732221-1-natechancellor@gmail.com> (raw)

When building with Clang:

drivers/gpu/drm/amd/amdgpu/amdgpu_device.c:4160:53: warning: overflow in
expression; result is -294967296 with type 'long' [-Winteger-overflow]
                expires = ktime_get_mono_fast_ns() + NSEC_PER_SEC * 4L;
                                                                  ^
1 warning generated.

Multiplication happens first due to order of operations and both
NSEC_PER_SEC and 4 are long literals so the expression overflows. To
avoid this, make 4 an unsigned long long literal, which matches the
type of expires (u64).

Fixes: 3f12acc8d6d4 ("drm/amdgpu: put the audio codec into suspend state before gpu reset V3")
Link: https://github.com/ClangBuiltLinux/linux/issues/1017
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 6f93af972b0a..caa38e7d502e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -4157,7 +4157,7 @@ static int amdgpu_device_suspend_display_audio(struct amdgpu_device *adev)
 		 * the audio controller default autosuspend delay setting.
 		 * 4S used here is guaranteed to cover that.
 		 */
-		expires = ktime_get_mono_fast_ns() + NSEC_PER_SEC * 4L;
+		expires = ktime_get_mono_fast_ns() + NSEC_PER_SEC * 4ULL;
 
 	while (!pm_runtime_status_suspended(&(p->dev))) {
 		if (!pm_runtime_suspend(&(p->dev)))

base-commit: fb9d670f57e3f6478602328bbbf71138be06ca4f
-- 
2.26.2

