drm/drm_exec: fix up contended obj when num_objects is 0
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 6.6.158, 6.12.111, 6.18.53, 7.2.7
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
In the Linux kernel, the following vulnerability has been resolved: drm/drm_exec: fix up contended obj when num_objects is 0 drm_exec_prepare_array() silently returns success without calling drm_exec_lock_contended() when num_objects is zero. This breaks the invariant upheld by drm_exec_lock_obj(), where every entry point into the locking sequence must first attempt to lock any previously contended object before proceeding. Drivers that chain multiple drm_exec_prepare_array() calls per drm_exec_until_all_locked() iteration (e.g. amdgpu's userq signal/wait ioctls, which prepare separate read and write BO arrays) can pass an empty array for one of the two calls. If contention is hit while preparing the non-empty array, exec->contended is set and the loop retries; on retry, the empty-array call preceding it is a no-op that never clears exec->contended, so drm_exec_retry_on_contention() immediately jumps back to the top of the loop without ever reaching the call that would resolve the contention. This spins forever. Fix it by having drm_exec_prepare_array() call drm_exec_lock_contended() directly when num_objects is zero, so a pending contended object dont loop infinitely.
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From 09593216bff15866f95c8ad406cb7fdcec1ee40a · fixed in 506cfed91e50cc8055799480a2fde5a18f63a21c; From 09593216bff15866f95c8ad406cb7fdcec1ee40a · fixed in 831cd124ce99c3e61266bed30519d52f7c26abed; From 09593216bff15866f95c8ad406cb7fdcec1ee40a · fixed in f3e74866018dab793ebee1fdf0ef34f7271d1f8c; From 09593216bff15866f95c8ad406cb7fdcec1ee40a · fixed in a565022c02f218ec9789c2baf4690792e7a48cbb; From 09593216bff15866f95c8ad406cb7fdcec1ee40a · fixed in 159720704d9d652b64390c11fb971e15b0a78d23
- Linux Linux
6.6
- KernelLinux
From 6.6.0 · fixed in 6.6.158; From 6.7.0 · fixed in 6.12.111; From 6.13.0 · fixed in 6.18.53; From 6.19.0 · fixed in 7.2.7