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| author | Marek Vasut <marex@denx.de> | 2021-09-17 02:59:13 +0200 |
|---|---|---|
| committer | Rob Clark <robdclark@chromium.org> | 2021-10-11 17:30:53 -0700 |
| commit | 171316a68d9a8e0d9e28b7cf4c15afc4c6244a4e (patch) | |
| tree | 84dc8a5115fb439137ee9e9c114dc78fc02fc977 /drivers/gpu | |
| parent | efb8a170a367fa898d7848c4e74c1c20222e0d91 (diff) | |
| download | linux-171316a68d9a8e0d9e28b7cf4c15afc4c6244a4e.tar.bz2 | |
drm/msm: Avoid potential overflow in timeout_to_jiffies()
The return type of ktime_divns() is s64. The timeout_to_jiffies() currently
assigns the result of this ktime_divns() to unsigned long, which on 32 bit
systems may overflow. Furthermore, the result of this function is sometimes
also passed to functions which expect signed long, dma_fence_wait_timeout()
is one such example.
Fix this by adjusting the type of remaining_jiffies to s64, so we do not
suffer overflow there, and return a value limited to range of 0..INT_MAX,
which is safe for all usecases of this timeout.
The above overflow can be triggered if userspace passes in too large timeout
value, larger than INT_MAX / HZ seconds. The kernel detects it and complains
about "schedule_timeout: wrong timeout value %lx" and generates a warning
backtrace.
Note that this fixes commit 6cedb8b377bb ("drm/msm: avoid using 'timespec'"),
because the previously used timespec_to_jiffies() function returned unsigned
long instead of s64:
static inline unsigned long timespec_to_jiffies(const struct timespec *value)
Fixes: 6cedb8b377bb ("drm/msm: avoid using 'timespec'")
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jordan Crouse <jcrouse@codeaurora.org>
Cc: Rob Clark <robdclark@chromium.org>
Cc: stable@vger.kernel.org # 5.6+
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20210917005913.157379-1-marex@denx.de
Signed-off-by: Rob Clark <robdclark@chromium.org>
Diffstat (limited to 'drivers/gpu')
| -rw-r--r-- | drivers/gpu/drm/msm/msm_drv.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h index e99242164076..c552f0c3890c 100644 --- a/drivers/gpu/drm/msm/msm_drv.h +++ b/drivers/gpu/drm/msm/msm_drv.h @@ -504,7 +504,7 @@ static inline int align_pitch(int width, int bpp) static inline unsigned long timeout_to_jiffies(const ktime_t *timeout) { ktime_t now = ktime_get(); - unsigned long remaining_jiffies; + s64 remaining_jiffies; if (ktime_compare(*timeout, now) < 0) { remaining_jiffies = 0; @@ -513,7 +513,7 @@ static inline unsigned long timeout_to_jiffies(const ktime_t *timeout) remaining_jiffies = ktime_divns(rem, NSEC_PER_SEC / HZ); } - return remaining_jiffies; + return clamp(remaining_jiffies, 0LL, (s64)INT_MAX); } #endif /* __MSM_DRV_H__ */ |