CVE-2025-38058

In the Linux kernel, the following vulnerability has been resolved: __legitimize_mnt(): check for MNT_SYNC_UMOUNT should be under mount_lock ... or we risk stealing final mntput from sync umount - raising mnt_count after umount(2) has verified that victim is not busy, but before it has set MNT_SYNC_UMOUNT; in that case __legitimize_mnt() doesn't see that it's safe to quietly undo mnt_count increment and leaves dropping the reference to caller, where it'll be a full-blown mntput(). Check under mount_lock is needed; leaving the current one done before taking that makes no sense - it's nowhere near common enough to bother with.

• linux linux kernel (< 5.4.294) • linux linux kernel (>= 5.5 < 5.10.238) • linux linux kernel (>= 5.11 < 5.15.185) • linux linux kernel (>= 5.16 < 6.1.141) • linux linux kernel (>= 6.2 < 6.6.93) • linux linux kernel (>= 6.7 < 6.12.31) • linux linux kernel (>= 6.13 < 6.14.9) • linux linux kernel 6.15 • debian debian linux 11.0