Description
In the Linux kernel, the following vulnerability has been resolved: mm/page_alloc: clear page->private in free_pages_prepare() Several subsystems (slub, shmem, ttm, etc.) use page->private but don't clear it before freeing pages. When these pages are later allocated as high-order pages and split via split_page(), tail pages retain stale page->private values. This causes a use-after-free in the swap subsystem. The swap code uses page->private to track swap count continuations, assuming freshly allocated pages have page->private == 0. When stale values are present, swap_count_continued() incorrectly assumes the continuation list is valid and iterates over uninitialized page->lru containing LIST_POISON values, causing a crash: KASAN: maybe wild-memory-access in range [0xdead000000000100-0xdead000000000107] RIP: 0010:__do_sys_swapoff+0x1151/0x1860 Fix this by clearing page->private in free_pages_prepare(), ensuring all freed pages have clean state regardless of previous use.
Product status
3b8000ae185cb068adbda5f966a3835053c85fd4 (git) before 23b82b7a26182ad840ae67d390d7ec9771e8c00f
3b8000ae185cb068adbda5f966a3835053c85fd4 (git) before d757c793853ec5483eb41ec2942c300b8fa720fb
3b8000ae185cb068adbda5f966a3835053c85fd4 (git) before ac1ea219590c09572ed5992dc233bbf7bb70fef9
5.18
Any version before 5.18
6.18.16 (semver)
6.19.6 (semver)
7.0 (original_commit_for_fix)
References
git.kernel.org/...c/23b82b7a26182ad840ae67d390d7ec9771e8c00f
git.kernel.org/...c/d757c793853ec5483eb41ec2942c300b8fa720fb
git.kernel.org/...c/ac1ea219590c09572ed5992dc233bbf7bb70fef9