Description
In the Linux kernel, the following vulnerability has been resolved: mm/slub: reset KASAN tag in defer_free() before accessing freed memory When CONFIG_SLUB_TINY is enabled, kfree_nolock() calls kasan_slab_free() before defer_free(). On ARM64 with MTE (Memory Tagging Extension), kasan_slab_free() poisons the memory and changes the tag from the original (e.g., 0xf3) to a poison tag (0xfe). When defer_free() then tries to write to the freed object to build the deferred free list via llist_add(), the pointer still has the old tag, causing a tag mismatch and triggering a KASAN use-after-free report: BUG: KASAN: slab-use-after-free in defer_free+0x3c/0xbc mm/slub.c:6537 Write at addr f3f000000854f020 by task kworker/u8:6/983 Pointer tag: [f3], memory tag: [fe] Fix this by calling kasan_reset_tag() before accessing the freed memory. This is safe because defer_free() is part of the allocator itself and is expected to manipulate freed memory for bookkeeping purposes.
Product status
af92793e52c3a99b828ed4bdd277fd3e11c18d08 (git) before 65d4e5af2a2e82f4fc50d8259aee208fbc6b2c1d
af92793e52c3a99b828ed4bdd277fd3e11c18d08 (git) before 53ca00a19d345197a37a1bf552e8d1e7b091666c
6.18
Any version before 6.18
6.18.3 (semver)
6.19-rc2 (original_commit_for_fix)
References
git.kernel.org/...c/65d4e5af2a2e82f4fc50d8259aee208fbc6b2c1d
git.kernel.org/...c/53ca00a19d345197a37a1bf552e8d1e7b091666c