Previously, bcache hijacked the bi_end_io and bi_private fields of
the incoming bio when the backing device was in a detached state.
This is fragile and breaks if the bio is needed to be processed by
other layers.
This patch transitions to using a cloned bio embedded within a private
structure. This ensures the original bio's metadata remains untouched.
Fixes: 53280e3984 ("bcache: fix improper use of bi_end_io")
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Shida Zhang <zhangshida@kylinos.cn>
Acked-by: Coly Li <colyli@fnnas.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_execute_rq() with polling is used in kernel code paths such as
NVMe controller connect. The aggressive spinning in blk_hctx_poll()
can prevent the completion task from getting a chance to run, causing
a lockup.
The spinning with cpu_relax() doesn't yield CPU, so need_resched()
only becomes true on timer tick. This causes unnecessary spinning
while the completion task is already waiting to run.
Before commit f22ecf9c14, the loop would exit early because
task_is_running() was always true. After that commit removed the
check, the loop now spins until need_resched().
Fix this by using BLK_POLL_ONESHOT in blk_rq_poll_completion(). This
causes blk_hctx_poll() to poll once and return immediately, letting
the outer loop's cond_resched() yield CPU so the completion task can
run.
Fixes: f22ecf9c14 ("blk-mq: delete task running check in blk_hctx_poll()")
Cc: Diangang Li <lidiangang@bytedance.com>
Cc: Fengnan Chang <changfengnan@bytedance.com>
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Initialize _evtfd to -1 in struct dev_ctx to prevent garbage output
when running kublk in foreground mode. Without this, _evtfd is
zero-initialized to 0 (stdin), and ublk_send_dev_event() writes
binary data to stdin which appears as garbage on the terminal.
Also fix debug message format string.
Fixes: 6aecda00b7 ("selftests: ublk: add kernel selftests for ublk")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Fix error handling in ublk_start_daemon() when start_dev fails:
1. Call ublk_ctrl_stop_dev() to cancel inflight uring_cmd before
cleanup. Without this, the device deletion may hang waiting for
I/O completion that will never happen.
2. Add fail_start label so that pthread_join() is called on the
error path. This ensures proper thread cleanup when startup fails.
Fixes: 6aecda00b7 ("selftests: ublk: add kernel selftests for ublk")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Include cmd_inflight in ublk_thread_is_done() check. Without this,
the thread may exit before all FETCH commands are completed, which
may cause device deletion to hang.
Fixes: 6aecda00b7 ("selftests: ublk: add kernel selftests for ublk")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The Linux 6.19 merge window added the new BLKREPORTZONESV2 ioctl, and
with it the new BLK_ZONE_REP_CACHED and BLK_ZONE_COND_ACTIVE constants.
The two constants are defined as part of enums, which makes it very
painful for userspace to discover if they are present in the installed
system headers.
Use the #define to the same name trick to make them trivially
discoverable using CPP directives.
Fixes: 0bf0e2e466 ("block: track zone conditions")
Fixes: b30ffcdc0c ("block: introduce BLKREPORTZONESV2 ioctl")
Reported-by: Andrey Albershteyn <aalbersh@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When ublksrv runs inside a pid namespace, START/END_RECOVERY compared
the stored init-ns tgid against the userspace pid (getpid vnr), so the
check failed and control ops could not proceed. Compare against the
caller’s init-ns tgid and store that value, then translate it back to
the caller’s pid namespace when reporting GET_DEV_INFO so ublk list
shows a sensible pid.
Testing: start/recover in a pid namespace; `ublk list` shows
reasonable pid values in init, child, and sibling namespaces.
Fixes: c2c8089f32 ("ublk: validate ublk server pid")
Signed-off-by: Seamus Connor <sconnor@purestorage.com>
Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Any queue_limits_start_update() call must be followed either by a
queue_limits_commit_update() call or by a queue_limits_cancel_update()
call. Make sure that the error path near the start of
disk_update_zone_resources() follows this requirement. Remove the
"goto unfreeze" statement from that error path to make the code easier
to verify.
This was detected by annotating the queue_limits_*() calls with Clang
thread-safety attributes and by building the kernel with thread-safety
checking enabled. Without this patch and with thread-safety checking
enabled, the following error is reported:
block/blk-zoned.c:2020:1: error: mutex 'disk->queue->limits_lock' is not held on every path through here [-Werror,-Wthread-safety-analysis]
2020 | }
| ^
block/blk-zoned.c:1959:8: note: mutex acquired here
1959 | lim = queue_limits_start_update(q);
| ^
Cc: Damien Le Moal <dlemoal@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Fixes: bba4322e3f ("block: freeze queue when updating zone resources")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20260114192803.4171847-3-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
During device unmapping (triggered by module unload or explicit unmap),
a refcount underflow occurs causing a use-after-free warning:
[14747.574913] ------------[ cut here ]------------
[14747.574916] refcount_t: underflow; use-after-free.
[14747.574917] WARNING: lib/refcount.c:28 at refcount_warn_saturate+0x55/0x90, CPU#9: kworker/9:1/378
[14747.574924] Modules linked in: rnbd_client(-) rtrs_client rnbd_server rtrs_server rtrs_core ...
[14747.574998] CPU: 9 UID: 0 PID: 378 Comm: kworker/9:1 Tainted: G O N 6.19.0-rc3lblk-fnext+ #42 PREEMPT(voluntary)
[14747.575005] Workqueue: rnbd_clt_wq unmap_device_work [rnbd_client]
[14747.575010] RIP: 0010:refcount_warn_saturate+0x55/0x90
[14747.575037] Call Trace:
[14747.575038] <TASK>
[14747.575038] rnbd_clt_unmap_device+0x170/0x1d0 [rnbd_client]
[14747.575044] process_one_work+0x211/0x600
[14747.575052] worker_thread+0x184/0x330
[14747.575055] ? __pfx_worker_thread+0x10/0x10
[14747.575058] kthread+0x10d/0x250
[14747.575062] ? __pfx_kthread+0x10/0x10
[14747.575066] ret_from_fork+0x319/0x390
[14747.575069] ? __pfx_kthread+0x10/0x10
[14747.575072] ret_from_fork_asm+0x1a/0x30
[14747.575083] </TASK>
[14747.575096] ---[ end trace 0000000000000000 ]---
Befor this patch :-
The bug is a double kobject_put() on dev->kobj during device cleanup.
Kobject Lifecycle:
kobject_init_and_add() sets kobj.kref = 1 (initialization)
kobject_put() sets kobj.kref = 0 (should be called once)
* Before this patch:
rnbd_clt_unmap_device()
rnbd_destroy_sysfs()
kobject_del(&dev->kobj) [remove from sysfs]
kobject_put(&dev->kobj) PUT #1 (WRONG!)
kref: 1 to 0
rnbd_dev_release()
kfree(dev) [DEVICE FREED!]
rnbd_destroy_gen_disk() [use-after-free!]
rnbd_clt_put_dev()
refcount_dec_and_test(&dev->refcount)
kobject_put(&dev->kobj) PUT #2 (UNDERFLOW!)
kref: 0 to -1 [WARNING!]
The first kobject_put() in rnbd_destroy_sysfs() prematurely frees the
device via rnbd_dev_release(), then the second kobject_put() in
rnbd_clt_put_dev() causes refcount underflow.
* After this patch :-
Remove kobject_put() from rnbd_destroy_sysfs(). This function should
only remove sysfs visibility (kobject_del), not manage object lifetime.
Call Graph (FIXED):
rnbd_clt_unmap_device()
rnbd_destroy_sysfs()
kobject_del(&dev->kobj) [remove from sysfs only]
[kref unchanged: 1]
rnbd_destroy_gen_disk() [device still valid]
rnbd_clt_put_dev()
refcount_dec_and_test(&dev->refcount)
kobject_put(&dev->kobj) ONLY PUT (CORRECT!)
kref: 1 to 0 [BALANCED]
rnbd_dev_release()
kfree(dev) [CLEAN DESTRUCTION]
This follows the kernel pattern where sysfs removal (kobject_del) is
separate from object destruction (kobject_put).
Fixes: 581cf833ca ("block: rnbd: add .release to rnbd_dev_ktype")
Signed-off-by: Chaitanya Kulkarni <ckulkarnilinux@gmail.com>
Acked-by: Jack Wang <jinpu.wang@ionos.com>
Reviewed-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The commit d2fe192348 (“nvme: only allow entering LIVE from CONNECTING
state”) disallows controller state transitions directly from RESETTING
to LIVE. However, the NVMe PCIe subsystem reset path relies on this
transition to recover the controller on PowerPC (PPC) systems.
On PPC systems, issuing a subsystem reset causes a temporary loss of
communication with the NVMe adapter. A subsequent PCIe MMIO read then
triggers EEH recovery, which restores the PCIe link and brings the
controller back online. For EEH recovery to proceed correctly, the
controller must transition back to the LIVE state.
Due to the changes introduced by commit d2fe192348 (“nvme: only allow
entering LIVE from CONNECTING state”), the controller can no longer
transition directly from RESETTING to LIVE. As a result, EEH recovery
exits prematurely, leaving the controller stuck in the RESETTING state.
Fix this by explicitly transitioning the controller state from RESETTING
to CONNECTING and then to LIVE. This satisfies the updated state
transition rules and allows the controller to be successfully recovered
on PPC systems following a PCIe subsystem reset.
Cc: stable@vger.kernel.org
Fixes: d2fe192348 ("nvme: only allow entering LIVE from CONNECTING state")
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Commit edd17206e3 ("nvmet: remove redundant subsysnqn field from
ctrl") replaced ctrl->subsysnqn with ctrl->subsys->subsysnqn. This
change works as expected because both point to strings with the same
data. However, their memory allocation lengths differ. ctrl->subsysnqn
had the fixed size defined as NVMF_NQN_FILED_LEN, while
ctrl->subsys->subsysnqn has variable length determined by kstrndup().
Due to this difference, KASAN slab-out-of-bounds occurs at memcpy() in
nvmet_passthru_override_id_ctrl() after the commit. The failure can be
recreated by running the blktests test case nvme/033. To prevent such
failures, replace memcpy() with strscpy(), which copies only the string
length and avoids overruns.
Fixes: edd17206e3 ("nvmet: remove redundant subsysnqn field from ctrl")
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
When CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION is enabled, the null-blk
driver sets up fault injection support by creating the timeout_inject,
requeue_inject, and init_hctx_fault_inject configfs items as children
of the top-level nullbX configfs group.
However, when the nullbX device is removed, the references taken to
these fault-config configfs items are not released. As a result,
kmemleak reports a memory leak, for example:
unreferenced object 0xc00000021ff25c40 (size 32):
comm "mkdir", pid 10665, jiffies 4322121578
hex dump (first 32 bytes):
69 6e 69 74 5f 68 63 74 78 5f 66 61 75 6c 74 5f init_hctx_fault_
69 6e 6a 65 63 74 00 88 00 00 00 00 00 00 00 00 inject..........
backtrace (crc 1a018c86):
__kmalloc_node_track_caller_noprof+0x494/0xbd8
kvasprintf+0x74/0xf4
config_item_set_name+0xf0/0x104
config_group_init_type_name+0x48/0xfc
fault_config_init+0x48/0xf0
0xc0080000180559e4
configfs_mkdir+0x304/0x814
vfs_mkdir+0x49c/0x604
do_mkdirat+0x314/0x3d0
sys_mkdir+0xa0/0xd8
system_call_exception+0x1b0/0x4f0
system_call_vectored_common+0x15c/0x2ec
Fix this by explicitly releasing the references to the fault-config
configfs items when dropping the reference to the top-level nullbX
configfs group.
Cc: stable@vger.kernel.org
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Fixes: bb4c19e030 ("block: null_blk: make fault-injection dynamically configurable per device")
Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The auto-generated integrity buffer for writes needs to be fully
initialized before being passed to the underlying block device,
otherwise the uninitialized memory can be read back by userspace or
anyone with physical access to the storage device. If protection
information is generated, that portion of the integrity buffer is
already initialized. The integrity data is also zeroed if PI generation
is disabled via sysfs or the PI tuple size is 0. However, this misses
the case where PI is generated and the PI tuple size is nonzero, but the
metadata size is larger than the PI tuple. In this case, the remainder
("opaque") of the metadata is left uninitialized.
Generalize the BLK_INTEGRITY_CSUM_NONE check to cover any case when the
metadata is larger than just the PI tuple.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Fixes: c546d6f438 ("block: only zero non-PI metadata tuples in bio_integrity_prep")
Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
nvme_fabrics creates an NVMe/FC controller in following path:
nvmf_dev_write()
-> nvmf_create_ctrl()
-> nvme_fc_create_ctrl()
-> nvme_fc_init_ctrl()
nvme_fc_init_ctrl() allocates the admin blk-mq resources right after
nvme_add_ctrl() succeeds. If any of the subsequent steps fail (changing
the controller state, scheduling connect work, etc.), we jump to the
fail_ctrl path, which tears down the controller references but never
frees the admin queue/tag set. The leaked blk-mq allocations match the
kmemleak report seen during blktests nvme/fc.
Check ctrl->ctrl.admin_tagset in the fail_ctrl path and call
nvme_remove_admin_tag_set() when it is set so that all admin queue
allocations are reclaimed whenever controller setup aborts.
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Reviewed-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: Chaitanya Kulkarni <ckulkarnilinux@gmail.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Commit efa5630590 ("nvmet-tcp: Fix a kernel panic when host sends an invalid H2C PDU length")
added ttag bounds checking and data_offset
validation in nvmet_tcp_handle_h2c_data_pdu(), but it did not validate
whether the command's data structures (cmd->req.sg and cmd->iov) have
been properly initialized before processing H2C_DATA PDUs.
The nvmet_tcp_build_pdu_iovec() function dereferences these pointers
without NULL checks. This can be triggered by sending H2C_DATA PDU
immediately after the ICREQ/ICRESP handshake, before
sending a CONNECT command or NVMe write command.
Attack vectors that trigger NULL pointer dereferences:
1. H2C_DATA PDU sent before CONNECT → both pointers NULL
2. H2C_DATA PDU for READ command → cmd->req.sg allocated, cmd->iov NULL
3. H2C_DATA PDU for uninitialized command slot → both pointers NULL
The fix validates both cmd->req.sg and cmd->iov before calling
nvmet_tcp_build_pdu_iovec(). Both checks are required because:
- Uninitialized commands: both NULL
- READ commands: cmd->req.sg allocated, cmd->iov NULL
- WRITE commands: both allocated
Fixes: efa5630590 ("nvmet-tcp: Fix a kernel panic when host sends an invalid H2C PDU length")
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Shivam Kumar <kumar.shivam43666@gmail.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
A race condition exists between the async partition scan work and device
teardown that can lead to a use-after-free of ub->ub_disk:
1. ublk_ctrl_start_dev() schedules partition_scan_work after add_disk()
2. ublk_stop_dev() calls ublk_stop_dev_unlocked() which does:
- del_gendisk(ub->ub_disk)
- ublk_detach_disk() sets ub->ub_disk = NULL
- put_disk() which may free the disk
3. The worker ublk_partition_scan_work() then dereferences ub->ub_disk
leading to UAF
Fix this by using ublk_get_disk()/ublk_put_disk() in the worker to hold
a reference to the disk during the partition scan. The spinlock in
ublk_get_disk() synchronizes with ublk_detach_disk() ensuring the worker
either gets a valid reference or sees NULL and exits early.
Also change flush_work() to cancel_work_sync() to avoid running the
partition scan work unnecessarily when the disk is already detached.
Fixes: 7fc4da6a30 ("ublk: scan partition in async way")
Reported-by: Ruikai Peng <ruikai@pwno.io>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
nvme_set_app_tag() uses the app_tag value from the bio_integrity_payload
of the struct request's first bio. This assumes all the request's bios
have the same app_tag. However, it is possible for bios with different
app_tag values to be merged into a single request.
Add a check in blk_integrity_merge_{bio,rq}() to prevent the merging of
bios/requests with different app_tag values if BIP_CHECK_APPTAG is set.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Fixes: 3d8b5a22d4 ("block: add support to pass user meta buffer")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The unlikely() annotations on QUEUE_FLAG_QOS_ENABLED checks are
counterproductive. Writeback throttling (WBT) might be enabled by
default, mainly because CONFIG_BLK_WBT_MQ defaults to 'y'.
Branch profiling on Meta servers, which have WBT enabled, confirms 100%
misprediction rates on these checks.
Remove the unlikely() annotations to let the CPU's branch predictor
learn the actual behavior, potentially improving I/O path performance.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
loop_set_status() is allowed to change the loop device while there
are other openers of the device, even exclusive ones.
In this case, it causes a KASAN: slab-out-of-bounds Read in
ext4_search_dir(), since when looking for an entry in an inlined
directory, e_value_offs is changed underneath the filesystem by
loop_set_status().
Fix the problem by forbidding loop_set_status() from modifying the loop
device while there are exclusive openers of the device. This is similar
to the fix in loop_configure() by commit 33ec3e53e7 ("loop: Don't
change loop device under exclusive opener") alongside commit ecbe6bc000
("block: use bd_prepare_to_claim directly in the loop driver").
Reported-by: syzbot+3ee481e21fd75e14c397@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=3ee481e21fd75e14c397
Tested-by: syzbot+3ee481e21fd75e14c397@syzkaller.appspotmail.com
Tested-by: Yongpeng Yang <yangyongpeng@xiaomi.com>
Signed-off-by: Raphael Pinsonneault-Thibeault <rpthibeault@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The function bfq_bfqq_may_idle() was renamed as bfq_better_to_idle()
in commit 277a4a9b56 ("block, bfq: give a better name to
bfq_bfqq_may_idle"). Update the comment accordingly.
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull MD fixes from Yu Kuai:
"- Fix null-pointer dereference in raid5 sysfs group_thread_cnt store
(Tuo Li)
- Fix possible mempool corruption during raid1 raid_disks update via
sysfs (FengWei Shih)
- Fix logical_block_size configuration being overwritten during
super_1_validate() (Li Nan)
- Fix forward incompatibility with configurable logical block size:
arrays assembled on new kernels could not be assembled on kernels
<=6.18 due to non-zero reserved pad rejection (Li Nan)
- Fix static checker warning about iterator not incremented (Li Nan)"
* tag 'md-6.19-20251231' of gitolite.kernel.org:pub/scm/linux/kernel/git/mdraid/linux:
md: Fix forward incompatibility from configurable logical block size
md: Fix logical_block_size configuration being overwritten
md: suspend array while updating raid_disks via sysfs
md/raid5: fix possible null-pointer dereferences in raid5_store_group_thread_cnt()
md: Fix static checker warning in analyze_sbs
If an hctx has no software ctx mapped, blk_mq_map_swqueue() never
allocates tags and leaves hctx->tags NULL. The CPU hotplug offline
notifier can still run for that hctx, return early since hctx cannot
hold any requests.
Signed-off-by: Cong Zhang <cong.zhang@oss.qualcomm.com>
Fixes: bf0beec060 ("blk-mq: drain I/O when all CPUs in a hctx are offline")
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add header dependencies to kublk build rule so that changes to
kublk.h, ublk_dep.h, or utils.h trigger a rebuild.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add test_generic_15.sh to verify that async partition scan prevents
IO hang when reading partition tables.
The test creates ublk devices with fault_inject target and very large
delay (60s) to simulate blocked partition table reads, then kills the
daemon to verify proper state transitions without hanging:
1. Without recovery support:
- Create device with fault_inject and 60s delay
- Kill daemon while partition scan may be blocked
- Verify device transitions to DEAD state
2. With recovery support (-r 1):
- Create device with fault_inject, 60s delay, and recovery
- Kill daemon while partition scan may be blocked
- Verify device transitions to QUIESCED state
Before the async partition scan fix, killing the daemon during
partition scan would cause deadlock as partition scan held ub->mutex
while waiting for IO. With the async fix, partition scan happens in
a work function and flush_work() ensures proper synchronization.
Add _add_ublk_dev_no_settle() helper function to skip udevadm settle,
which would otherwise hang waiting for partition scan events to
complete when partition table read is delayed.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Implement async partition scan to avoid IO hang when reading partition
tables. Similar to nvme_partition_scan_work(), partition scanning is
deferred to a work queue to prevent deadlocks.
When partition scan happens synchronously during add_disk(), IO errors
can cause the partition scan to wait while holding ub->mutex, which
can deadlock with other operations that need the mutex.
Changes:
- Add partition_scan_work to ublk_device structure
- Implement ublk_partition_scan_work() to perform async scan
- Always suppress sync partition scan during add_disk()
- Schedule async work after add_disk() for trusted daemons
- Add flush_work() in ublk_stop_dev() before grabbing ub->mutex
Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>
Reported-by: Yoav Cohen <yoav@nvidia.com>
Closes: https://lore.kernel.org/linux-block/DM4PR12MB63280C5637917C071C2F0D65A9A8A@DM4PR12MB6328.namprd12.prod.outlook.com/
Fixes: 71f28f3136 ("ublk_drv: add io_uring based userspace block driver")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Route bfqg_stats_add_aux() time accumulation into the destination
stats object instead of the source, aligning with other stat fields.
Reviewed-by: Yu Kuai <yukuai@fnnas.com>
Signed-off-by: shechenglong <shechenglong@xfusion.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In raid1_reshape(), freeze_array() is called before modifying the r1bio
memory pool (conf->r1bio_pool) and conf->raid_disks, and
unfreeze_array() is called after the update is completed.
However, freeze_array() only waits until nr_sync_pending and
(nr_pending - nr_queued) of all buckets reaches zero. When an I/O error
occurs, nr_queued is increased and the corresponding r1bio is queued to
either retry_list or bio_end_io_list. As a result, freeze_array() may
unblock before these r1bios are released.
This can lead to a situation where conf->raid_disks and the mempool have
already been updated while queued r1bios, allocated with the old
raid_disks value, are later released. Consequently, free_r1bio() may
access memory out of bounds in put_all_bios() and release r1bios of the
wrong size to the new mempool, potentially causing issues with the
mempool as well.
Since only normal I/O might increase nr_queued while an I/O error occurs,
suspending the array avoids this issue.
Note: Updating raid_disks via ioctl SET_ARRAY_INFO already suspends
the array. Therefore, we suspend the array when updating raid_disks
via sysfs to avoid this issue too.
Signed-off-by: FengWei Shih <dannyshih@synology.com>
Link: https://lore.kernel.org/linux-raid/20251226101816.4506-1-dannyshih@synology.com
Signed-off-by: Yu Kuai <yukuai@fnnas.com>
The variable mddev->private is first assigned to conf and then checked:
conf = mddev->private;
if (!conf) ...
If conf is NULL, then mddev->private is also NULL. In this case,
null-pointer dereferences can occur when calling raid5_quiesce():
raid5_quiesce(mddev, true);
raid5_quiesce(mddev, false);
since mddev->private is assigned to conf again in raid5_quiesce(), and conf
is dereferenced in several places, for example:
conf->quiesce = 0;
wake_up(&conf->wait_for_quiescent);
To fix this issue, the function should unlock mddev and return before
invoking raid5_quiesce() when conf is NULL, following the existing pattern
in raid5_change_consistency_policy().
Fixes: fa1944bbe6 ("md/raid5: Wait sync io to finish before changing group cnt")
Signed-off-by: Tuo Li <islituo@gmail.com>
Reviewed-by: Xiao Ni <xni@redhat.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Link: https://lore.kernel.org/linux-raid/20251225130326.67780-1-islituo@gmail.com
Signed-off-by: Yu Kuai <yukuai@fnnas.com>
The "dev->clt_device_id" variable is set using ida_alloc_max() which
returns an int and in particular it returns negative error codes.
Change the type from u32 to int to fix the error checking.
Fixes: c9b5645fd8 ("block: rnbd-clt: Fix leaked ID in init_dev()")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If a ublk server process releases a ublk char device file, any requests
dispatched to the ublk server but not yet completed will retain a ref
value of UBLK_REFCOUNT_INIT. Before commit e63d2228ef ("ublk: simplify
aborting ublk request"), __ublk_fail_req() would decrement the reference
count before completing the failed request. However, that commit
optimized __ublk_fail_req() to call __ublk_complete_rq() directly
without decrementing the request reference count.
The leaked reference count incorrectly allows user copy and zero copy
operations on the completed ublk request. It also triggers the
WARN_ON_ONCE(refcount_read(&io->ref)) warnings in ublk_queue_reinit()
and ublk_deinit_queue().
Commit c5c5eb24ed ("ublk: avoid ublk_io_release() called after ublk
char dev is closed") already fixed the issue for ublk devices using
UBLK_F_SUPPORT_ZERO_COPY or UBLK_F_AUTO_BUF_REG. However, the reference
count leak also affects UBLK_F_USER_COPY, the other reference-counted
data copy mode. Fix the condition in ublk_check_and_reset_active_ref()
to include all reference-counted data copy modes. This ensures that any
ublk requests still owned by the ublk server when it exits have their
reference counts reset to 0.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Fixes: e63d2228ef ("ublk: simplify aborting ublk request")
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Various code assumes that the integrity interval is at least 1 sector
and evenly divides the logical block size. Add these checks to
blk_validate_integrity_limits(). This guards against block drivers that
report invalid interval_exp values.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The PI tuple must be contained within the metadata value, so validate
that pi_offset + pi_tuple_size <= metadata_size. This guards against
block drivers that report invalid pi_offset values.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If kstrdup() fails in init_dev(), then the newly allocated ID is lost.
Fixes: 64e8a6ece1 ("block/rnbd-clt: Dynamically alloc buffer for pathname & blk_symlink_name")
Signed-off-by: Thomas Fourier <fourier.thomas@gmail.com>
Acked-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When one process(such as udev) opens ublk block device (e.g., to read
the partition table via bdev_open()), a deadlock[1] can occur:
1. bdev_open() grabs disk->open_mutex
2. The process issues read I/O to ublk backend to read partition table
3. In __ublk_complete_rq(), blk_update_request() or blk_mq_end_request()
runs bio->bi_end_io() callbacks
4. If this triggers fput() on file descriptor of ublk block device, the
work may be deferred to current task's task work (see fput() implementation)
5. This eventually calls blkdev_release() from the same context
6. blkdev_release() tries to grab disk->open_mutex again
7. Deadlock: same task waiting for a mutex it already holds
The fix is to run blk_update_request() and blk_mq_end_request() with bottom
halves disabled. This forces blkdev_release() to run in kernel work-queue
context instead of current task work context, and allows ublk server to make
forward progress, and avoids the deadlock.
Fixes: 71f28f3136 ("ublk_drv: add io_uring based userspace block driver")
Link: https://github.com/ublk-org/ublksrv/issues/170 [1]
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>
[axboe: rewrite comment in ublk]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The "zone_capacity=%umb" option is no longer used. The effective option
is now "zone_capacity_mb=%u", so update the documentation accordingly.
Signed-off-by: Yongpeng Yang <yangyongpeng@xiaomi.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In the queue_rq path, zlo->state is accessed without locking, and direct
access may read stale data. This patch uses READ_ONCE() to read
zlo->state and data_race() to silence code checkers, and changes all
assignments to use WRITE_ONCE().
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Yongpeng Yang <yangyongpeng@xiaomi.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When lo->lo_mutex is not held, direct access may read stale data. This
patch uses READ_ONCE() to read lo->lo_state and data_race() to silence
code checkers, and changes all assignments to use WRITE_ONCE().
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Yongpeng Yang <yangyongpeng@xiaomi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Secondary temperature thresholds (temp2_{min,max}) were not reported
properly on this NVMe SSD. This resulted in an error while attempting to
read these values with sensors(1):
ERROR: Can't get value of subfeature temp2_min: I/O error
ERROR: Can't get value of subfeature temp2_max: I/O error
Add the device to the nvme_id_table with the
NVME_QUIRK_NO_SECONDARY_TEMP_THRESH flag to suppress access to all non-
composite temperature thresholds.
Cc: stable@vger.kernel.org
Tested-by: Wu Haotian <rigoligo03@gmail.com>
Signed-off-by: Ilikara Zheng <ilikara@aosc.io>
Signed-off-by: Keith Busch <kbusch@kernel.org>
When wbt_enable_default() is moved out of queue freezing in elevator_change(),
it can cause the wbt inflight counter to become negative (-1), leading to hung
tasks in the writeback path. Tasks get stuck in wbt_wait() because the counter
is in an inconsistent state.
The issue occurs because wbt_enable_default() could race with IO submission,
allowing the counter to be decremented before proper initialization. This manifests
as:
rq_wait[0]:
inflight: -1
has_waiters: True
rwb_enabled() checks the state, which can be updated exactly between wbt_wait()
(rq_qos_throttle()) and wbt_track()(rq_qos_track()), then the inflight counter
will become negative.
And results in hung task warnings like:
task:kworker/u24:39 state:D stack:0 pid:14767
Call Trace:
rq_qos_wait+0xb4/0x150
wbt_wait+0xa9/0x100
__rq_qos_throttle+0x24/0x40
blk_mq_submit_bio+0x672/0x7b0
...
Fix this by:
1. Splitting wbt_enable_default() into:
- __wbt_enable_default(): Returns true if wbt_init() should be called
- wbt_enable_default(): Wrapper for existing callers (no init)
- wbt_init_enable_default(): New function that checks and inits WBT
2. Using wbt_init_enable_default() in blk_register_queue() to ensure
proper initialization during queue registration
3. Move wbt_init() out of wbt_enable_default() which is only for enabling
disabled wbt from bfq and iocost, and wbt_init() isn't needed. Then the
original lock warning can be avoided.
4. Removing the ELEVATOR_FLAG_ENABLE_WBT_ON_EXIT flag and its handling
code since it's no longer needed
This ensures WBT is properly initialized before any IO can be submitted,
preventing the counter from going negative.
Cc: Nilay Shroff <nilay@linux.ibm.com>
Cc: Yu Kuai <yukuai@fnnas.com>
Cc: Guangwu Zhang <guazhang@redhat.com>
Fixes: 78c271344b ("block: move wbt_enable_default() out of queue freezing from sched ->exit()")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The ublk selftests cover every data copy mode except user copy. Add
tests for user copy based on the existing test suite:
- generic_14 ("basic recover function verification (user copy)") based
on generic_04 and generic_05
- null_03 ("basic IO test with user copy") based on null_01 and null_02
- loop_06 ("write and verify over user copy") based on loop_01 and
loop_03
- loop_07 ("mkfs & mount & umount with user copy") based on loop_02 and
loop_04
- stripe_05 ("write and verify test on user copy") based on stripe_03
- stripe_06 ("mkfs & mount & umount on user copy") based on stripe_02
and stripe_04
- stress_06 ("run IO and remove device (user copy)") based on stress_01
and stress_03
- stress_07 ("run IO and kill ublk server (user copy)") based on
stress_02 and stress_04
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The ublk selftests mock ublk server kublk supports every data copy mode
except user copy. Add support for user copy to kublk, enabled via the
--user_copy (-u) command line argument. On writes, issue pread() calls
to copy the write data into the ublk_io's buffer before dispatching the
write to the target implementation. On reads, issue pwrite() calls to
copy read data from the ublk_io's buffer before committing the request.
Copy in 2 KB chunks to provide some coverage of the offseting logic.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
