Activity log
- Created & dismissed (max. allowed matches exceeded) suggestion
mm/memory-failure: fix hugetlb_lock AA deadlock in get_huge_page_for_hwpoison
In the Linux kernel, the following vulnerability has been resolved: mm/memory-failure: fix hugetlb_lock AA deadlock in get_huge_page_for_hwpoison Two concurrent madvise(MADV_HWPOISON) calls on the same hugetlb page can trigger a recursive spinlock self-deadlock (AA deadlock) on hugetlb_lock when racing with a concurrent unmap: thread#0 thread#1 -------- -------- madvise(folio, MADV_HWPOISON) -> poisons the folio successfully madvise(folio, MADV_HWPOISON) unmap(folio) try_memory_failure_hugetlb get_huge_page_for_hwpoison spin_lock_irq(&hugetlb_lock) <- held __get_huge_page_for_hwpoison hugetlb_update_hwpoison() -> MF_HUGETLB_FOLIO_PRE_POISONED goto out: folio_put() refcount: 1 -> 0 free_huge_folio() spin_lock_irqsave(&hugetlb_lock) -> AA DEADLOCK! The out: path in __get_huge_page_for_hwpoison() calls folio_put() to drop the GUP reference while the hugetlb_lock is still held by the hugetlb.c wrapper get_huge_page_for_hwpoison(). If concurrent unmap has released the page table mapping reference, folio_put() drops the folio refcount to zero, triggering free_huge_folio() which attempts to re-acquire the non-recursive hugetlb_lock. Fix this by moving hugetlb_lock acquisition from the hugetlb.c wrapper into get_huge_page_for_hwpoison(). Place spin_unlock_irq() before the folio_put() at the out: label so the folio is always released outside the lock. [akpm@linux-foundation.org: fix race, rename label per Miaohe]
References
Affected products
- <fc3ff42cb0cbf947e4600ae9761c3783760050e2
- =<6.18.*
- =<6.1.*
- <77b73b54801ae7137479c141fd0473a491c1dc48
- ==5.18
- <dd77a83915b07e2b0205adb284f08b39ae31dc4b
- =<6.6.*
- =<7.0.*
- =<6.12.*
- <bf7ba8f96c258c30393814491930ae4ecdc5fe5e
- <5.16
- <5.18
- <3c2d42b8ee345b17a4ba56b0f6492d1ff4c1178e
- <a33bfed648c10f5a1519981dbfad80841191edc8
- ==62d1655b922958826b7ec22682c3141746f75064
- =<*