kernel/linux.git/drivers/md/dm.c, branch v6.18.42

dm: avoid leaking the caller's thread keyring via the table device file

2026-08-03T09:22:11+00:00

[ Upstream commit 981ccd97f7153d310dfa92a534525bbaf46752c2 ] The refactoring in commit a28d893eb327 ("md: port block device access to file") accidentally causes the caller's thread keyring to be kept alive long beyond the caller's lifetime. As a result, "cryptsetup luksSuspend" silently fails to wipe the LUKS volume key from memory. In detail: "cryptsetup luksOpen" uses its supposedly ephemeral thread keyring to pass the volume key to the kernel. dm-crypt's crypt_set_keyring_key() copies the key material into its own crypt_config structure and then drops its own reference to the key in the keyring with key_put(). With this fix, restoring pre-v6.9 behavior, the copy in the thread keyring is then promptly garbage collected, such that exactly one copy of the volume key remains. This single copy is correctly wiped from memory on "cryptsetup luksSuspend". Without this fix, the thread keyring and the volume key in it remains. This second copy is only freed on "luksClose". "luksSuspend" neither knows about this copy nor has any way to remove it, so the key remains recoverable from RAM after a suspend that is documented to have wiped it. This fix should not introduce new security problems, as the code is anyway gated by CAP_SYS_ADMIN. The device-mapper core, not the calling task, is the legitimate owner of this long-lived file. Fixes: a28d893eb327 ("md: port block device access to file") Closes: https://gitlab.com/cryptsetup/cryptsetup/-/work_items/993 Link: https://www.speicherleck.de/iblech/cryptsetup-luksSuspend-issue-reproduction/ Signed-off-by: Ingo Blechschmidt Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Tested-by: Ondrej Kozina Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

dm: add WQ_PERCPU to alloc_workqueue users

2026-05-23T11:06:23+00:00

[ Upstream commit d4880868670198df321627a949e7b7f2d76cf54e ] This continues the effort to refactor workqueue APIs, which began with the introduction of new workqueues and a new alloc_workqueue flag in: commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq") commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag") The refactoring is going to alter the default behavior of alloc_workqueue() to be unbound by default. With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND), any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND must now use WQ_PERCPU. For more details see the Link tag below. In order to keep alloc_workqueue() behavior identical, explicitly request WQ_PERCPU. Link: https://lore.kernel.org/all/20250221112003.1dSuoGyc@linutronix.de/ Suggested-by: Tejun Heo Signed-off-by: Marco Crivellari Signed-off-by: Mikulas Patocka Stable-dep-of: e4979f4fac4d ("md: remove unused static md_wq workqueue") Signed-off-by: Sasha Levin

dm: use bio_clone_blkg_association

2026-02-26T22:59:18+00:00

[ Upstream commit 2df8b310bcfe76827fd71092f58a2493ee6590b0 ] The origin bio carries blk-cgroup information which could be set from foreground(task_css(css) - wbc->wb->blkcg_css), so the blkcg won't control buffer io since commit ca522482e3eaf ("dm: pass NULL bdev to bio_alloc_clone"). The synchronous io is still under control by blkcg, because 'bio->bi_blkg' is set by io submitting task which has been added into 'cgroup.procs'. Fix it by using bio_clone_blkg_association when submitting a cloned bio. Link: https://bugzilla.kernel.org/show_bug.cgi?id=220985 Fixes: ca522482e3eaf ("dm: pass NULL bdev to bio_alloc_clone") Reported-by: Zhihao Cheng Signed-off-by: Mikulas Patocka Tested-by: Zhihao Cheng Signed-off-by: Sasha Levin

dm: fix failure when empty flush's bi_sector points beyond the device end

2025-11-20T18:50:42+00:00

An empty flush bio can have arbitrary bi_sector. The commit 2b1c6d7a890a introduced a regression that device mapper would fail an empty flush bio with -EIO if the sector pointed beyond the end of the device. The commit introduced an optimization, that optimization would pass flushes to __split_and_process_bio and __split_and_process_bio is not prepared to handle empty bios. Fix this bug by passing only non-empty flushes to __split_and_process_bio - non-empty flushes must have valid bi_sector. Empty bios will go through __send_empty_flush, as they did before the optimization. This problem can be reproduced by running the lvm2 test: make check_local T=lvconvert-thin.sh LVM_TEST_PREFER_BRD=0 Signed-off-by: Mikulas Patocka Fixes: 2b1c6d7a890a ("dm: optimize REQ_PREFLUSH with data when using the linear target") Reported-by: Zdenek Kabelac Reviewed-by: Bart Van Assche

Merge tag 'for-6.18/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

2025-10-04T01:48:02+00:00

Pull device mapper updates from Mikulas Patocka: - a new dm-pcache target for read/write caching on persistent memory - fix typos in docs - misc small refactoring - mark dm-error with DM_TARGET_PASSES_INTEGRITY - dm-request-based: fix NULL pointer dereference and quiesce_depth out of sync - dm-linear: optimize REQ_PREFLUSH - dm-vdo: return error on corrupted metadata - dm-integrity: support asynchronous hash interface * tag 'for-6.18/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (27 commits) dm raid: use proper md_ro_state enumerators dm-integrity: prefer synchronous hash interface dm-integrity: enable asynchronous hash interface dm-integrity: rename internal_hash dm-integrity: add the "offset" argument dm-integrity: allocate the recalculate buffer with kmalloc dm-integrity: introduce integrity_kmap and integrity_kunmap dm-integrity: replace bvec_kmap_local with kmap_local_page dm-integrity: use internal variable for digestsize dm vdo: return error on corrupted metadata in start_restoring_volume functions dm vdo: Update code to use mem_is_zero dm: optimize REQ_PREFLUSH with data when using the linear target dm-pcache: use int type to store negative error codes dm: fix "writen"->"written" dm-pcache: cleanup: fix coding style report by checkpatch.pl dm-pcache: remove ctrl_lock for pcache_cache_segment dm: fix NULL pointer dereference in __dm_suspend() dm: fix queue start/stop imbalance under suspend/load/resume races dm-pcache: add persistent cache target in device-mapper dm error: mark as DM_TARGET_PASSES_INTEGRITY ...

dm: optimize REQ_PREFLUSH with data when using the linear target

2025-09-18T10:58:02+00:00

If the table has only linear targets and there is just one underlying device, we can optimize REQ_PREFLUSH with data - we don't have to split it to two bios - a flush and a write. We can pass it to the linear target directly. Signed-off-by: Mikulas Patocka Tested-by: Bart Van Assche Reviewed-by: Bart Van Assche

dm: fix NULL pointer dereference in __dm_suspend()

2025-08-26T14:46:52+00:00

There is a race condition between dm device suspend and table load that can lead to null pointer dereference. The issue occurs when suspend is invoked before table load completes: BUG: kernel NULL pointer dereference, address: 0000000000000054 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 6 PID: 6798 Comm: dmsetup Not tainted 6.6.0-g7e52f5f0ca9b #62 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 RIP: 0010:blk_mq_wait_quiesce_done+0x0/0x50 Call Trace: blk_mq_quiesce_queue+0x2c/0x50 dm_stop_queue+0xd/0x20 __dm_suspend+0x130/0x330 dm_suspend+0x11a/0x180 dev_suspend+0x27e/0x560 ctl_ioctl+0x4cf/0x850 dm_ctl_ioctl+0xd/0x20 vfs_ioctl+0x1d/0x50 __se_sys_ioctl+0x9b/0xc0 __x64_sys_ioctl+0x19/0x30 x64_sys_call+0x2c4a/0x4620 do_syscall_64+0x9e/0x1b0 The issue can be triggered as below: T1 T2 dm_suspend table_load __dm_suspend dm_setup_md_queue dm_mq_init_request_queue blk_mq_init_allocated_queue => q->mq_ops = set->ops; (1) dm_stop_queue / dm_wait_for_completion => q->tag_set NULL pointer! (2) => q->tag_set = set; (3) Fix this by checking if a valid table (map) exists before performing request-based suspend and waiting for target I/O. When map is NULL, skip these table-dependent suspend steps. Even when map is NULL, no I/O can reach any target because there is no table loaded; I/O submitted in this state will fail early in the DM layer. Skipping the table-dependent suspend logic in this case is safe and avoids NULL pointer dereferences. Fixes: c4576aed8d85 ("dm: fix request-based dm's use of dm_wait_for_completion") Cc: stable@vger.kernel.org Signed-off-by: Zheng Qixing Signed-off-by: Mikulas Patocka

dm: fix queue start/stop imbalance under suspend/load/resume races

2025-08-26T14:46:32+00:00

When suspend and load run concurrently, before q->mq_ops is set in blk_mq_init_allocated_queue(), __dm_suspend() skip dm_stop_queue(). As a result, the queue's quiesce depth is not incremented. Later, once table load has finished and __dm_resume() runs, which triggers q->quiesce_depth ==0 warning in blk_mq_unquiesce_queue(): Call Trace: dm_start_queue+0x16/0x20 [dm_mod] __dm_resume+0xac/0xb0 [dm_mod] dm_resume+0x12d/0x150 [dm_mod] do_resume+0x2c2/0x420 [dm_mod] dev_suspend+0x30/0x130 [dm_mod] ctl_ioctl+0x402/0x570 [dm_mod] dm_ctl_ioctl+0x23/0x30 [dm_mod] Fix this by explicitly tracking whether the request queue was stopped in __dm_suspend() via a new DMF_QUEUE_STOPPED flag. Only call dm_start_queue() in __dm_resume() if the queue was actually stopped. Fixes: e70feb8b3e68 ("blk-mq: support concurrent queue quiesce/unquiesce") Cc: stable@vger.kernel.org Signed-off-by: Zheng Qixing Signed-off-by: Mikulas Patocka

block: switch ->getgeo() to struct gendisk

2025-08-13T06:59:29+00:00

Instances are happier that way and it makes more sense anyway - the only part of the result that is related to partition we are given is the start sector, and that has been filled in by the caller. Everything else is a function of the disk. Only one instance (DASD) is ever looking at anything other than bdev->bd_disk and that one is trivial to adjust. Reviewed-by: Martin K. Petersen Reviewed-by: Christoph Hellwig Acked-by: Jens Axboe Signed-off-by: Al Viro

Merge tag 'for-6.17/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

2025-08-04T15:58:53+00:00

Pull device mapper updates from Mikulas Patocka: - fix checking for request-based stackable devices (dm-table) - fix corrupt_bio_byte setup checks (dm-flakey) - add support for resync w/o metadata devices (dm raid) - small code simplification (dm, dm-mpath, vm-vdo, dm-raid) - remove support for asynchronous hashes (dm-verity) - close smatch warning (dm-zoned-target) - update the documentation and enable inline-crypto passthrough (dm-thin) * tag 'for-6.17/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: dm: set DM_TARGET_PASSES_CRYPTO feature for dm-thin dm-thin: update the documentation dm-raid: do not include dm-core.h vdo: omit need_resched() before cond_resched() md: dm-zoned-target: Initialize return variable r to avoid uninitialized use dm-verity: remove support for asynchronous hashes dm-mpath: don't print the "loaded" message if registering fails dm-mpath: make dm_unregister_path_selector return void dm: ima: avoid extra calls to strlen() dm: Simplify dm_io_complete() dm: Remove unnecessary return in dm_zone_endio() dm raid: add support for resync w/o metadata devices dm-flakey: Fix corrupt_bio_byte setup checks dm-table: fix checking for rq stackable devices