diff options
| author | Jack Wang <jinpu.wang@ionos.com> | 2026-01-20 11:24:56 +0100 |
|---|---|---|
| committer | Yu Kuai <yukuai@fnnas.com> | 2026-01-26 13:36:06 +0800 |
| commit | 46ef85f854dfa9d5226b3c1c46493d79556c9589 (patch) | |
| tree | f6cc2246c97394768c0e9fea605e7161200a5b0c /drivers/md | |
| parent | d119bd2e1643cc023210ff3c6f0657e4f914e71d (diff) | |
md/bitmap: fix GPF in write_page caused by resize race
A General Protection Fault occurs in write_page() during array resize:
RIP: 0010:write_page+0x22b/0x3c0 [md_mod]
This is a use-after-free race between bitmap_daemon_work() and
__bitmap_resize(). The daemon iterates over `bitmap->storage.filemap`
without locking, while the resize path frees that storage via
md_bitmap_file_unmap(). `quiesce()` does not stop the md thread,
allowing concurrent access to freed pages.
Fix by holding `mddev->bitmap_info.mutex` during the bitmap update.
Link: https://lore.kernel.org/linux-raid/20260120102456.25169-1-jinpu.wang@ionos.com
Closes: https://lore.kernel.org/linux-raid/CAMGffE=Mbfp=7xD_hYxXk1PAaCZNSEAVeQGKGy7YF9f2S4=NEA@mail.gmail.com/T/#u
Cc: stable@vger.kernel.org
Fixes: d60b479d177a ("md/bitmap: add bitmap_resize function to allow bitmap resizing.")
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Yu Kuai <yukuai@fnnas.com>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/md-bitmap.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c index dbe4c4b9a1da..1d4a050dab3a 100644 --- a/drivers/md/md-bitmap.c +++ b/drivers/md/md-bitmap.c @@ -2453,6 +2453,7 @@ static int __bitmap_resize(struct bitmap *bitmap, sector_t blocks, memcpy(page_address(store.sb_page), page_address(bitmap->storage.sb_page), sizeof(bitmap_super_t)); + mutex_lock(&bitmap->mddev->bitmap_info.mutex); spin_lock_irq(&bitmap->counts.lock); md_bitmap_file_unmap(&bitmap->storage); bitmap->storage = store; @@ -2560,7 +2561,7 @@ static int __bitmap_resize(struct bitmap *bitmap, sector_t blocks, set_page_attr(bitmap, i, BITMAP_PAGE_DIRTY); } spin_unlock_irq(&bitmap->counts.lock); - + mutex_unlock(&bitmap->mddev->bitmap_info.mutex); if (!init) { __bitmap_unplug(bitmap); bitmap->mddev->pers->quiesce(bitmap->mddev, 0); |