diff options
| author | Jinjiang Tu <tujinjiang@huawei.com> | 2025-07-24 17:09:56 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-08-20 18:40:49 +0200 |
| commit | b625883ccbcc2b57808db51d1375b1d7b9bcb3e5 (patch) | |
| tree | ab30306f3f82cb99cc104dd8abe039c9dbf276ba | |
| parent | 55c232d7e0241f1d5120b595e7a9de24c75ed3d8 (diff) | |
mm/smaps: fix race between smaps_hugetlb_range and migration
[ Upstream commit 45d19b4b6c2d422771c29b83462d84afcbb33f01 ]
smaps_hugetlb_range() handles the pte without holdling ptl, and may be
concurrenct with migration, leaing to BUG_ON in pfn_swap_entry_to_page().
The race is as follows.
smaps_hugetlb_range migrate_pages
huge_ptep_get
remove_migration_ptes
folio_unlock
pfn_swap_entry_folio
BUG_ON
To fix it, hold ptl lock in smaps_hugetlb_range().
Link: https://lkml.kernel.org/r/20250724090958.455887-1-tujinjiang@huawei.com
Link: https://lkml.kernel.org/r/20250724090958.455887-2-tujinjiang@huawei.com
Fixes: 25ee01a2fca0 ("mm: hugetlb: proc: add hugetlb-related fields to /proc/PID/smaps")
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Brahmajit Das <brahmajit.xyz@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joern Engel <joern@logfs.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | fs/proc/task_mmu.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 751479eb128f..0102ab3aaec1 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1020,10 +1020,13 @@ static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask, { struct mem_size_stats *mss = walk->private; struct vm_area_struct *vma = walk->vma; - pte_t ptent = huge_ptep_get(walk->mm, addr, pte); struct folio *folio = NULL; bool present = false; + spinlock_t *ptl; + pte_t ptent; + ptl = huge_pte_lock(hstate_vma(vma), walk->mm, pte); + ptent = huge_ptep_get(walk->mm, addr, pte); if (pte_present(ptent)) { folio = page_folio(pte_page(ptent)); present = true; @@ -1042,6 +1045,7 @@ static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask, else mss->private_hugetlb += huge_page_size(hstate_vma(vma)); } + spin_unlock(ptl); return 0; } #else |