drm/msm: Avoid potential overflow in timeout_to_jiffies()
commit 171316a6 upstream. 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 6cedb8b3 ("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: 6cedb8b3 ("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> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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