Description
In the Linux kernel, the following vulnerability has been resolved: mm/damon/sysfs: fix use-after-free in state_show() state_show() reads kdamond->damon_ctx without holding damon_sysfs_lock. This allows a use-after-free race: CPU 0 CPU 1 ----- ----- state_show() damon_sysfs_turn_damon_on() ctx = kdamond->damon_ctx; mutex_lock(&damon_sysfs_lock); damon_destroy_ctx(kdamond->damon_ctx); kdamond->damon_ctx = NULL; mutex_unlock(&damon_sysfs_lock); damon_is_running(ctx); /* ctx is freed */ mutex_lock(&ctx->kdamond_lock); /* UAF */ (The race can also occur with damon_sysfs_kdamonds_rm_dirs() and damon_sysfs_kdamond_release(), which free or replace the context under damon_sysfs_lock.) Fix by taking damon_sysfs_lock before dereferencing the context, mirroring the locking used in pid_show(). The bug has existed since state_show() first accessed kdamond->damon_ctx.
Product status
a61ea561c87139992fe32afdee48a6f6b85d824a (git) before 3858c44341ad49dc7544b19cc9f9ecffaa7cc50e
a61ea561c87139992fe32afdee48a6f6b85d824a (git) before 60d7a3d2b985a395318faa1d88da6915fad11c19
a61ea561c87139992fe32afdee48a6f6b85d824a (git) before 26d29b2ac87a2989071755f9828ebf839b560d4c
a61ea561c87139992fe32afdee48a6f6b85d824a (git) before 4e87f461d61959647464a94d11ae15c011be58ce
a61ea561c87139992fe32afdee48a6f6b85d824a (git) before 3260a3f0828e06f5f13fac69fb1999a6d60d9cff
5.18
Any version before 5.18
6.1.153 (semver)
6.6.107 (semver)
6.12.48 (semver)
6.16.8 (semver)
6.17 (original_commit_for_fix)
References
lists.debian.org/debian-lts-announce/2025/10/msg00008.html
git.kernel.org/...c/3858c44341ad49dc7544b19cc9f9ecffaa7cc50e
git.kernel.org/...c/60d7a3d2b985a395318faa1d88da6915fad11c19
git.kernel.org/...c/26d29b2ac87a2989071755f9828ebf839b560d4c
git.kernel.org/...c/4e87f461d61959647464a94d11ae15c011be58ce
git.kernel.org/...c/3260a3f0828e06f5f13fac69fb1999a6d60d9cff
