linux/drivers/md, branch v6.12

dm-cache: fix warnings about duplicate slab caches

2024-11-11T16:04:39Z

The commit 4c39529663b9 adds a warning about duplicate cache names if CONFIG_DEBUG_VM is selected. These warnings are triggered by the dm-cache code. The dm-cache code allocates a slab cache for each device. This commit changes it to allocate just one slab cache in the module init function. Signed-off-by: Mikulas Patocka Fixes: 4c39529663b9 ("slab: Warn on duplicate cache names when DEBUG_VM=y")

dm-bufio: fix warnings about duplicate slab caches

2024-11-11T16:04:18Z

The commit 4c39529663b9 adds a warning about duplicate cache names if CONFIG_DEBUG_VM is selected. These warnings are triggered by the dm-bufio code. The dm-bufio code allocates a slab cache with each client. It is not possible to preallocate the caches in the module init function because the size of auxiliary per-buffer data is not known at this point. So, this commit changes dm-bufio so that it appends a unique atomic value to the cache name, to avoid the warnings. Signed-off-by: Mikulas Patocka Fixes: 4c39529663b9 ("slab: Warn on duplicate cache names when DEBUG_VM=y")

Merge tag 'for-6.12/dm-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

2024-11-06T17:56:47Z

Pull device mapper fixes from Mikulas Patocka: - fix memory safety bugs in dm-cache - fix restart/panic logic in dm-verity - fix 32-bit unsigned integer overflow in dm-unstriped - fix a device mapper crash if blk_alloc_disk fails * tag 'for-6.12/dm-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: dm cache: fix potential out-of-bounds access on the first resume dm cache: optimize dirty bit checking with find_next_bit when resizing dm cache: fix out-of-bounds access to the dirty bitset when resizing dm cache: fix flushing uninitialized delayed_work on cache_ctr error dm cache: correct the number of origin blocks to match the target length dm-verity: don't crash if panic_on_corruption is not selected dm-unstriped: cast an operand to sector_t to prevent potential uint32_t overflow dm: fix a crash if blk_alloc_disk fails

dm cache: fix potential out-of-bounds access on the first resume

2024-11-04T16:39:31Z

Out-of-bounds access occurs if the fast device is expanded unexpectedly before the first-time resume of the cache table. This happens because expanding the fast device requires reloading the cache table for cache_create to allocate new in-core data structures that fit the new size, and the check in cache_preresume is not performed during the first resume, leading to the issue. Reproduce steps: 1. prepare component devices: dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" dmsetup create cdata --table "0 65536 linear /dev/sdc 8192" dmsetup create corig --table "0 524288 linear /dev/sdc 262144" dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct 2. load a cache table of 512 cache blocks, and deliberately expand the fast device before resuming the cache, making the in-core data structures inadequate. dmsetup create cache --notable dmsetup reload cache --table "0 524288 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" dmsetup reload cdata --table "0 131072 linear /dev/sdc 8192" dmsetup resume cdata dmsetup resume cache 3. suspend the cache to write out the in-core dirty bitset and hint array, leading to out-of-bounds access to the dirty bitset at offset 0x40: dmsetup suspend cache KASAN reports: BUG: KASAN: vmalloc-out-of-bounds in is_dirty_callback+0x2b/0x80 Read of size 8 at addr ffffc90000085040 by task dmsetup/90 (...snip...) The buggy address belongs to the virtual mapping at [ffffc90000085000, ffffc90000087000) created by: cache_ctr+0x176a/0x35f0 (...snip...) Memory state around the buggy address: ffffc90000084f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc90000084f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 >ffffc90000085000: 00 00 00 00 00 00 00 00 f8 f8 f8 f8 f8 f8 f8 f8 ^ ffffc90000085080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc90000085100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 Fix by checking the size change on the first resume. Signed-off-by: Ming-Hung Tsai Fixes: f494a9c6b1b6 ("dm cache: cache shrinking support") Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka Acked-by: Joe Thornber

dm cache: optimize dirty bit checking with find_next_bit when resizing

2024-11-04T16:39:31Z

When shrinking the fast device, dm-cache iteratively searches for a dirty bit among the cache blocks to be dropped, which is less efficient. Use find_next_bit instead, as it is twice as fast as the iterative approach with test_bit. Signed-off-by: Ming-Hung Tsai Fixes: f494a9c6b1b6 ("dm cache: cache shrinking support") Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka Acked-by: Joe Thornber

dm cache: fix out-of-bounds access to the dirty bitset when resizing

2024-11-04T16:39:31Z

dm-cache checks the dirty bits of the cache blocks to be dropped when shrinking the fast device, but an index bug in bitset iteration causes out-of-bounds access. Reproduce steps: 1. create a cache device of 1024 cache blocks (128 bytes dirty bitset) dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" dmsetup create cdata --table "0 131072 linear /dev/sdc 8192" dmsetup create corig --table "0 524288 linear /dev/sdc 262144" dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct dmsetup create cache --table "0 524288 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" 2. shrink the fast device to 512 cache blocks, triggering out-of-bounds access to the dirty bitset (offset 0x80) dmsetup suspend cache dmsetup reload cdata --table "0 65536 linear /dev/sdc 8192" dmsetup resume cdata dmsetup resume cache KASAN reports: BUG: KASAN: vmalloc-out-of-bounds in cache_preresume+0x269/0x7b0 Read of size 8 at addr ffffc900000f3080 by task dmsetup/131 (...snip...) The buggy address belongs to the virtual mapping at [ffffc900000f3000, ffffc900000f5000) created by: cache_ctr+0x176a/0x35f0 (...snip...) Memory state around the buggy address: ffffc900000f2f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc900000f3000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffffc900000f3080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ^ ffffc900000f3100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc900000f3180: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 Fix by making the index post-incremented. Signed-off-by: Ming-Hung Tsai Fixes: f494a9c6b1b6 ("dm cache: cache shrinking support") Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka Acked-by: Joe Thornber

dm cache: fix flushing uninitialized delayed_work on cache_ctr error

2024-11-04T16:39:31Z

An unexpected WARN_ON from flush_work() may occur when cache creation fails, caused by destroying the uninitialized delayed_work waker in the error path of cache_create(). For example, the warning appears on the superblock checksum error. Reproduce steps: dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" dmsetup create cdata --table "0 65536 linear /dev/sdc 8192" dmsetup create corig --table "0 524288 linear /dev/sdc 262144" dd if=/dev/urandom of=/dev/mapper/cmeta bs=4k count=1 oflag=direct dmsetup create cache --table "0 524288 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" Kernel logs: (snip) WARNING: CPU: 0 PID: 84 at kernel/workqueue.c:4178 __flush_work+0x5d4/0x890 Fix by pulling out the cancel_delayed_work_sync() from the constructor's error path. This patch doesn't affect the use-after-free fix for concurrent dm_resume and dm_destroy (commit 6a459d8edbdb ("dm cache: Fix UAF in destroy()")) as cache_dtr is not changed. Signed-off-by: Ming-Hung Tsai Fixes: 6a459d8edbdb ("dm cache: Fix UAF in destroy()") Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka Acked-by: Joe Thornber

dm cache: correct the number of origin blocks to match the target length

2024-11-04T16:39:31Z

When creating a cache device, the actual size of the cache origin might be greater than the specified cache target length. In such case, the number of origin blocks should match the cache target length, not the full size of the origin device, since access beyond the cache target is not possible. This issue occurs when reducing the origin device size using lvm, as lvreduce preloads the new cache table before resuming the cache origin, which can result in incorrect sizes for the discard bitset and smq hotspot blocks. Reproduce steps: 1. create a cache device consists of 4096 origin blocks dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" dmsetup create cdata --table "0 65536 linear /dev/sdc 8192" dmsetup create corig --table "0 524288 linear /dev/sdc 262144" dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct dmsetup create cache --table "0 524288 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" 2. reduce the cache origin to 2048 oblocks, in lvreduce's approach dmsetup reload corig --table "0 262144 linear /dev/sdc 262144" dmsetup reload cache --table "0 262144 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" dmsetup suspend cache dmsetup suspend corig dmsetup suspend cdata dmsetup suspend cmeta dmsetup resume corig dmsetup resume cdata dmsetup resume cmeta dmsetup resume cache 3. shutdown the cache, and check the number of discard blocks in superblock. The value is expected to be 2048, but actually is 4096. dmsetup remove cache corig cdata cmeta dd if=/dev/sdc bs=1c count=8 skip=224 2>/dev/null | hexdump -e '1/8 "%u\n"' Fix by correcting the origin_blocks initialization in cache_create and removing the unused origin_sectors from struct cache_args accordingly. Signed-off-by: Ming-Hung Tsai Fixes: c6b4fcbad044 ("dm: add cache target") Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka Acked-by: Joe Thornber

dm-verity: don't crash if panic_on_corruption is not selected

2024-11-04T16:39:23Z

If the user sets panic_on_error and doesn't set panic_on_corruption, dm-verity should not panic on data mismatch. But, currently it panics, because it treats data mismatch as I/O error. This commit fixes the logic so that if there is data mismatch and panic_on_corruption or restart_on_corruption is not selected, the system won't restart or panic. Signed-off-by: Mikulas Patocka Reviewed-by: Sami Tolvanen Fixes: f811b83879fb ("dm-verity: introduce the options restart_on_error and panic_on_error")

dm-unstriped: cast an operand to sector_t to prevent potential uint32_t overflow

2024-11-04T16:34:56Z

This was found by a static analyzer. There may be a potential integer overflow issue in unstripe_ctr(). uc->unstripe_offset and uc->unstripe_width are defined as "sector_t"(uint64_t), while uc->unstripe, uc->chunk_size and uc->stripes are all defined as "uint32_t". The result of the calculation will be limited to "uint32_t" without correct casting. So, we recommend adding an extra cast to prevent potential integer overflow. Fixes: 18a5bf270532 ("dm: add unstriped target") Signed-off-by: Zichen Xie Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org