From: Marek Vasut <marex@denx.de>
To: linux-arm-msm@vger.kernel.org
Cc: freedreno@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
Marek Vasut <marex@denx.de>, Arnd Bergmann <arnd@arndb.de>,
Jordan Crouse <jcrouse@codeaurora.org>,
Rob Clark <robdclark@chromium.org>,
stable@vger.kernel.org
Subject: [PATCH] drm/msm: Avoid potential overflow in timeout_to_jiffies()
Date: Fri, 17 Sep 2021 02:59:13 +0200 [thread overview]
Message-ID: <20210917005913.157379-1-marex@denx.de> (raw)
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+
---
NOTE: This is related to Mesa MR
https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12886
---
drivers/gpu/drm/msm/msm_drv.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
index 0b2686b060c73..d96b254b8aa46 100644
--- a/drivers/gpu/drm/msm/msm_drv.h
+++ b/drivers/gpu/drm/msm/msm_drv.h
@@ -543,7 +543,7 @@ 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;
@@ -552,7 +552,7 @@ 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__ */
--
2.33.0
next reply other threads:[~2021-09-17 0:59 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-17 0:59 Marek Vasut [this message]
2021-09-17 7:03 ` [PATCH] drm/msm: Avoid potential overflow in timeout_to_jiffies() Arnd Bergmann
2021-10-01 17:17 ` Dmitry Baryshkov
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