1.5 KiB
CVE-2025-21853
Description
In the Linux kernel, the following vulnerability has been resolved:bpf: avoid holding freeze_mutex during mmap operationWe use map->freeze_mutex to prevent races between map_freeze() andmemory mapping BPF map contents with writable permissions. The way wenaively do this means we'll hold freeze_mutex for entire duration of allthe mm and VMA manipulations, which is completely unnecessary. This canpotentially also lead to deadlocks, as reported by syzbot in [0].So, instead, hold freeze_mutex only during writeability checks, bump(proactively) "write active" count for the map, unlock the mutex andproceed with mmap logic. And only if something went wrong during mmaplogic, then undo that "write active" counter increment. [0] https://lore.kernel.org/bpf/678dcbc9.050a0220.303755.0066.GAE@google.com/
POC
Reference
No PoCs from references.