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| author | Jack Wang <jinpu.wang@ionos.com> | 2026-01-20 13:24:56 +0300 |
|---|---|---|
| committer | Sasha Levin <sashal@kernel.org> | 2026-03-04 15:21:16 +0300 |
| commit | 9a6f8cd28bb9bb6ed86a6df19331fb08016dee7f (patch) | |
| tree | ed774517268171748f7e2aa836a9a5a94f1a0ce8 /drivers/md | |
| parent | b04baa848c0543b240b1bd8aecff470382f6f154 (diff) | |
| download | linux-9a6f8cd28bb9bb6ed86a6df19331fb08016dee7f.tar.xz | |
md/bitmap: fix GPF in write_page caused by resize race
[ Upstream commit 46ef85f854dfa9d5226b3c1c46493d79556c9589 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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 84b7e2af6dba..7bb56d0491a2 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); |