diff options
| author | Vishal Moola (Oracle) <vishal.moola@gmail.com> | 2024-09-14 21:41:18 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-09-17 09:58:04 +0200 |
| commit | 2a058ab3286d6475b2082b90c2d2182d2fea4b39 (patch) | |
| tree | e521b1aa290facd3b3dc9d63a662be1520450aca /mm | |
| parent | resource: fix region_intersects() vs add_memory_driver_managed() (diff) | |
| download | linux-2a058ab3286d6475b2082b90c2d2182d2fea4b39.tar.xz linux-2a058ab3286d6475b2082b90c2d2182d2fea4b39.zip | |
mm: change vmf_anon_prepare() to __vmf_anon_prepare()
Some callers of vmf_anon_prepare() may not want us to release the per-VMA
lock ourselves. Rename vmf_anon_prepare() to __vmf_anon_prepare() and let
the callers drop the lock when desired.
Also, make vmf_anon_prepare() a wrapper that releases the per-VMA lock
itself for any callers that don't care.
This is in preparation to fix this bug reported by syzbot:
https://lore.kernel.org/linux-mm/00000000000067c20b06219fbc26@google.com/
Link: https://lkml.kernel.org/r/20240914194243.245-1-vishal.moola@gmail.com
Fixes: 9acad7ba3e25 ("hugetlb: use vmf_anon_prepare() instead of anon_vma_prepare()")
Reported-by: syzbot+2dab93857ee95f2eeb08@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-mm/00000000000067c20b06219fbc26@google.com/
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/internal.h | 11 | ||||
| -rw-r--r-- | mm/memory.c | 8 |
2 files changed, 13 insertions, 6 deletions
diff --git a/mm/internal.h b/mm/internal.h index b4d86436565b..a963f67d3452 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -310,7 +310,16 @@ static inline void wake_throttle_isolated(pg_data_t *pgdat) wake_up(wqh); } -vm_fault_t vmf_anon_prepare(struct vm_fault *vmf); +vm_fault_t __vmf_anon_prepare(struct vm_fault *vmf); +static inline vm_fault_t vmf_anon_prepare(struct vm_fault *vmf) +{ + vm_fault_t ret = __vmf_anon_prepare(vmf); + + if (unlikely(ret & VM_FAULT_RETRY)) + vma_end_read(vmf->vma); + return ret; +} + vm_fault_t do_swap_page(struct vm_fault *vmf); void folio_rotate_reclaimable(struct folio *folio); bool __folio_end_writeback(struct folio *folio); diff --git a/mm/memory.c b/mm/memory.c index 3c01d68065be..95c347ba6305 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3259,7 +3259,7 @@ static inline vm_fault_t vmf_can_call_fault(const struct vm_fault *vmf) } /** - * vmf_anon_prepare - Prepare to handle an anonymous fault. + * __vmf_anon_prepare - Prepare to handle an anonymous fault. * @vmf: The vm_fault descriptor passed from the fault handler. * * When preparing to insert an anonymous page into a VMA from a @@ -3273,7 +3273,7 @@ static inline vm_fault_t vmf_can_call_fault(const struct vm_fault *vmf) * Return: 0 if fault handling can proceed. Any other value should be * returned to the caller. */ -vm_fault_t vmf_anon_prepare(struct vm_fault *vmf) +vm_fault_t __vmf_anon_prepare(struct vm_fault *vmf) { struct vm_area_struct *vma = vmf->vma; vm_fault_t ret = 0; @@ -3281,10 +3281,8 @@ vm_fault_t vmf_anon_prepare(struct vm_fault *vmf) if (likely(vma->anon_vma)) return 0; if (vmf->flags & FAULT_FLAG_VMA_LOCK) { - if (!mmap_read_trylock(vma->vm_mm)) { - vma_end_read(vma); + if (!mmap_read_trylock(vma->vm_mm)) return VM_FAULT_RETRY; - } } if (__anon_vma_prepare(vma)) ret = VM_FAULT_OOM; |