171316a68d
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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.