Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: - [Medium] Inadequate overflow check in `drm_timeout_rel_to_jiffies` allows `nsecs_to_jiffies64` to wrap around for large timeouts on 64-bit systems. --
--- Patch [2]: [PATCH v2 2/6] drm: Add drm_timeout_rel_to_jiffies() --- commit 8056b58ff81363ebaf4bcf9d659c346706fc5b99 Author: Maíra Canal <[email protected]> drm: Add drm_timeout_rel_to_jiffies() This commit introduces a core helper to convert a relative timeout in nanoseconds to jiffies. It aims to unify similar conversions currently done in drivers like i915 and v3d. > diff --git a/drivers/gpu/drm/drm_timeout.c b/drivers/gpu/drm/drm_timeout.c > index 78e9f65e54779..18c2719d1fe92 100644 > --- a/drivers/gpu/drm/drm_timeout.c > +++ b/drivers/gpu/drm/drm_timeout.c [ ... ] > @@ -45,3 +46,36 @@ signed long drm_timeout_abs_to_jiffies(int64_t > timeout_nsec) > return timeout_jiffies64 + 1; > } > EXPORT_SYMBOL(drm_timeout_abs_to_jiffies); > + > +/** > + * drm_timeout_rel_to_jiffies - calculate jiffies timeout from relative value [ ... ] > +unsigned long drm_timeout_rel_to_jiffies(u64 timeout_nsec) > +{ > + /* make 0 timeout means poll, as for the absolute variant */ > + if (timeout_nsec == 0) > + return 0; > + > + /* nsecs_to_jiffies64() does not guard against overflow */ > + if ((NSEC_PER_SEC % HZ) != 0 && > + div_u64(timeout_nsec, NSEC_PER_SEC) >= MAX_JIFFY_OFFSET / HZ) > + return MAX_JIFFY_OFFSET; [Severity: Medium] Is it possible this overflow guard is ineffective on 64-bit systems? Since MAX_JIFFY_OFFSET is extremely large on 64-bit architectures, and nsecs_to_jiffies64() internally uses a multiplication that can overflow a u64 at roughly 65 years, a very large timeout_nsec might bypass this check. If it bypasses this check, the value could still wrap around during the nsecs_to_jiffies64() conversion, causing the wait to return almost immediately instead of blocking as requested. > + > + return min_t(u64, MAX_JIFFY_OFFSET, nsecs_to_jiffies64(timeout_nsec) + > 1); > +} -- Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=2
