kernel/linux.git/drivers/nvme/target/core.c, branch linux-7.0.y

nvmet: avoid recursive nvmet-wq flush in nvmet_ctrl_free

2026-05-14T13:31:14+00:00

commit aade8abd8b868b6ffa9697aadaea28ec7f65bee6 upstream. nvmet_tcp_release_queue_work() runs on nvmet-wq and can drop the final controller reference through nvmet_cq_put(). If that triggers nvmet_ctrl_free(), the teardown path flushes ctrl->async_event_work on the same nvmet-wq. Call chain: nvmet_tcp_schedule_release_queue() kref_put(&queue->kref, nvmet_tcp_release_queue) nvmet_tcp_release_queue() queue_work(nvmet_wq, &queue->release_work) <--- nvmet_wq process_one_work() nvmet_tcp_release_queue_work() nvmet_cq_put(&queue->nvme_cq) nvmet_cq_destroy() nvmet_ctrl_put(cq->ctrl) nvmet_ctrl_free() flush_work(&ctrl->async_event_work) <--- nvmet_wq Previously Scheduled by :- nvmet_add_async_event queue_work(nvmet_wq, &ctrl->async_event_work); This trips lockdep with a possible recursive locking warning. [ 5223.015876] run blktests nvme/003 at 2026-04-07 20:53:55 [ 5223.061801] loop0: detected capacity change from 0 to 2097152 [ 5223.072206] nvmet: adding nsid 1 to subsystem blktests-subsystem-1 [ 5223.088368] nvmet_tcp: enabling port 0 (127.0.0.1:4420) [ 5223.126086] nvmet: Created discovery controller 1 for subsystem nqn.2014-08.org.nvmexpress.discovery for NQN nqn.2014-08.org.nvmexpress:uuid:0f01fb42-9f7f-4856-b0b3-51e60b8de349. [ 5223.128453] nvme nvme1: new ctrl: NQN "nqn.2014-08.org.nvmexpress.discovery", addr 127.0.0.1:4420, hostnqn: nqn.2014-08.org.nvmexpress:uuid:0f01fb42-9f7f-4856-b0b3-51e60b8de349 [ 5233.199447] nvme nvme1: Removing ctrl: NQN "nqn.2014-08.org.nvmexpress.discovery" [ 5233.227718] ============================================ [ 5233.231283] WARNING: possible recursive locking detected [ 5233.234696] 7.0.0-rc3nvme+ #20 Tainted: G O N [ 5233.238434] -------------------------------------------- [ 5233.241852] kworker/u192:6/2413 is trying to acquire lock: [ 5233.245429] ffff888111632548 ((wq_completion)nvmet-wq){+.+.}-{0:0}, at: touch_wq_lockdep_map+0x26/0x90 [ 5233.251438] but task is already holding lock: [ 5233.255254] ffff888111632548 ((wq_completion)nvmet-wq){+.+.}-{0:0}, at: process_one_work+0x5cc/0x6e0 [ 5233.261125] other info that might help us debug this: [ 5233.265333] Possible unsafe locking scenario: [ 5233.269217] CPU0 [ 5233.270795] ---- [ 5233.272436] lock((wq_completion)nvmet-wq); [ 5233.275241] lock((wq_completion)nvmet-wq); [ 5233.278020] *** DEADLOCK *** [ 5233.281793] May be due to missing lock nesting notation [ 5233.286195] 3 locks held by kworker/u192:6/2413: [ 5233.289192] #0: ffff888111632548 ((wq_completion)nvmet-wq){+.+.}-{0:0}, at: process_one_work+0x5cc/0x6e0 [ 5233.294569] #1: ffffc9000e2a7e40 ((work_completion)(&queue->release_work)){+.+.}-{0:0}, at: process_one_work+0x1c5/0x6e0 [ 5233.300128] #2: ffffffff82d7dc40 (rcu_read_lock){....}-{1:3}, at: __flush_work+0x62/0x530 [ 5233.304290] stack backtrace: [ 5233.306520] CPU: 4 UID: 0 PID: 2413 Comm: kworker/u192:6 Tainted: G O N 7.0.0-rc3nvme+ #20 PREEMPT(full) [ 5233.306524] Tainted: [O]=OOT_MODULE, [N]=TEST [ 5233.306525] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 [ 5233.306527] Workqueue: nvmet-wq nvmet_tcp_release_queue_work [nvmet_tcp] [ 5233.306532] Call Trace: [ 5233.306534] [ 5233.306536] dump_stack_lvl+0x73/0xb0 [ 5233.306552] print_deadlock_bug+0x225/0x2f0 [ 5233.306556] __lock_acquire+0x13f0/0x2290 [ 5233.306563] lock_acquire+0xd0/0x300 [ 5233.306565] ? touch_wq_lockdep_map+0x26/0x90 [ 5233.306571] ? __flush_work+0x20b/0x530 [ 5233.306573] ? touch_wq_lockdep_map+0x26/0x90 [ 5233.306577] touch_wq_lockdep_map+0x3b/0x90 [ 5233.306580] ? touch_wq_lockdep_map+0x26/0x90 [ 5233.306583] ? __flush_work+0x20b/0x530 [ 5233.306585] __flush_work+0x268/0x530 [ 5233.306588] ? __pfx_wq_barrier_func+0x10/0x10 [ 5233.306594] ? xen_error_entry+0x30/0x60 [ 5233.306600] nvmet_ctrl_free+0x140/0x310 [nvmet] [ 5233.306617] nvmet_cq_put+0x74/0x90 [nvmet] [ 5233.306629] nvmet_tcp_release_queue_work+0x19f/0x360 [nvmet_tcp] [ 5233.306634] process_one_work+0x206/0x6e0 [ 5233.306640] worker_thread+0x184/0x320 [ 5233.306643] ? __pfx_worker_thread+0x10/0x10 [ 5233.306646] kthread+0xf1/0x130 [ 5233.306648] ? __pfx_kthread+0x10/0x10 [ 5233.306651] ret_from_fork+0x355/0x450 [ 5233.306653] ? __pfx_kthread+0x10/0x10 [ 5233.306656] ret_from_fork_asm+0x1a/0x30 [ 5233.306664] There is also no need to flush async_event_work from controller teardown. The admin queue teardown already fails outstanding AER requests before the final controller put :- nvmet_sq_destroy(admin sq) nvmet_async_events_failall(ctrl) The controller has already been removed from the subsystem list before nvmet_ctrl_free() quiesces outstanding work. Replace flush_work() with cancel_work_sync() so a pending async_event_work item is canceled and a running instance is waited on without recursing into the same workqueue. Fixes: 06406d81a2d7 ("nvmet: cancel fatal error and flush async work before free controller") Cc: stable@vger.kernel.org Reviewed-by: Christoph Hellwig Signed-off-by: Chaitanya Kulkarni Signed-off-by: Keith Busch Signed-off-by: Greg Kroah-Hartman

Merge tag 'block-7.0-20260312' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux

2026-03-13T17:13:06+00:00

Pull block fixes from Jens Axboe: - NVMe pull request via Keith: - Fix nvme-pci IRQ race and slab-out-of-bounds access - Fix recursive workqueue locking for target async events - Various cleanups - Fix a potential NULL pointer dereference in ublk on size setting - ublk automatic partition scanning fix - Two s390 dasd fixes * tag 'block-7.0-20260312' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: nvme: Annotate struct nvme_dhchap_key with __counted_by nvme-core: do not pass empty queue_limits to blk_mq_alloc_queue() nvme-pci: Fix race bug in nvme_poll_irqdisable() nvmet: move async event work off nvmet-wq nvme-pci: Fix slab-out-of-bounds in nvme_dbbuf_set s390/dasd: Copy detected format information to secondary device s390/dasd: Move quiesce state with pprc swap ublk: don't clear GD_SUPPRESS_PART_SCAN for unprivileged daemons ublk: fix NULL pointer dereference in ublk_ctrl_set_size()

nvmet: move async event work off nvmet-wq

2026-03-10T15:20:28+00:00

For target nvmet_ctrl_free() flushes ctrl->async_event_work. If nvmet_ctrl_free() runs on nvmet-wq, the flush re-enters workqueue completion for the same worker:- A. Async event work queued on nvmet-wq (prior to disconnect): nvmet_execute_async_event() queue_work(nvmet_wq, &ctrl->async_event_work) nvmet_add_async_event() queue_work(nvmet_wq, &ctrl->async_event_work) B. Full pre-work chain (RDMA CM path): nvmet_rdma_cm_handler() nvmet_rdma_queue_disconnect() __nvmet_rdma_queue_disconnect() queue_work(nvmet_wq, &queue->release_work) process_one_work() lock((wq_completion)nvmet-wq) <--------- 1st nvmet_rdma_release_queue_work() C. Recursive path (same worker): nvmet_rdma_release_queue_work() nvmet_rdma_free_queue() nvmet_sq_destroy() nvmet_ctrl_put() nvmet_ctrl_free() flush_work(&ctrl->async_event_work) __flush_work() touch_wq_lockdep_map() lock((wq_completion)nvmet-wq) <--------- 2nd Lockdep splat: ============================================ WARNING: possible recursive locking detected 6.19.0-rc3nvme+ #14 Tainted: G N -------------------------------------------- kworker/u192:42/44933 is trying to acquire lock: ffff888118a00948 ((wq_completion)nvmet-wq){+.+.}-{0:0}, at: touch_wq_lockdep_map+0x26/0x90 but task is already holding lock: ffff888118a00948 ((wq_completion)nvmet-wq){+.+.}-{0:0}, at: process_one_work+0x53e/0x660 3 locks held by kworker/u192:42/44933: #0: ffff888118a00948 ((wq_completion)nvmet-wq){+.+.}-{0:0}, at: process_one_work+0x53e/0x660 #1: ffffc9000e6cbe28 ((work_completion)(&queue->release_work)){+.+.}-{0:0}, at: process_one_work+0x1c5/0x660 #2: ffffffff82d4db60 (rcu_read_lock){....}-{1:3}, at: __flush_work+0x62/0x530 Workqueue: nvmet-wq nvmet_rdma_release_queue_work [nvmet_rdma] Call Trace: __flush_work+0x268/0x530 nvmet_ctrl_free+0x140/0x310 [nvmet] nvmet_cq_put+0x74/0x90 [nvmet] nvmet_rdma_free_queue+0x23/0xe0 [nvmet_rdma] nvmet_rdma_release_queue_work+0x19/0x50 [nvmet_rdma] process_one_work+0x206/0x660 worker_thread+0x184/0x320 kthread+0x10c/0x240 ret_from_fork+0x319/0x390 Move async event work to a dedicated nvmet-aen-wq to avoid reentrant flush on nvmet-wq. Reviewed-by: Christoph Hellwig Signed-off-by: Chaitanya Kulkarni Signed-off-by: Keith Busch

Convert more 'alloc_obj' cases to default GFP_KERNEL arguments

2026-02-22T04:03:00+00:00

This converts some of the visually simpler cases that have been split over multiple lines. I only did the ones that are easy to verify the resulting diff by having just that final GFP_KERNEL argument on the next line. Somebody should probably do a proper coccinelle script for this, but for me the trivial script actually resulted in an assertion failure in the middle of the script. I probably had made it a bit _too_ trivial. So after fighting that far a while I decided to just do some of the syntactically simpler cases with variations of the previous 'sed' scripts. The more syntactically complex multi-line cases would mostly really want whitespace cleanup anyway. Signed-off-by: Linus Torvalds

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

kernel.h: drop hex.h and update all hex.h users

2026-01-21T03:44:19+00:00

Remove from and update all users/callers of hex.h interfaces to directly #include as part of the process of putting kernel.h on a diet. Removing hex.h from kernel.h means that 36K C source files don't have to pay the price of parsing hex.h for the roughly 120 C source files that need it. This change has been build-tested with allmodconfig on most ARCHes. Also, all users/callers of in the entire source tree have been updated if needed (if not already #included). Link: https://lkml.kernel.org/r/20251215005206.2362276-1-rdunlap@infradead.org Signed-off-by: Randy Dunlap Reviewed-by: Andy Shevchenko Cc: Ingo Molnar Cc: Yury Norov (NVIDIA) Signed-off-by: Andrew Morton

nvme: fix typo error in nvme target

2025-12-04T22:46:16+00:00

Fix two spelling mistakes. Reviewed-by: Christoph Hellwig Signed-off-by: Chu Guangqing Signed-off-by: Keith Busch

nvmet: remove redundant subsysnqn field from ctrl

2025-12-01T21:45:53+00:00

The subsysnqn field in the nvmet controller structure is redundant, since the subsystem NQN can always be accessed via the controller's subsystem reference. Remove this field to save memory and avoid unnecessary duplication. Signed-off-by: Max Gurtovoy Signed-off-by: Keith Busch

nvmet: add sanity checks when freeing subsystem

2025-12-01T16:53:17+00:00

Add WARN_ON_ONCE checks in nvmet_subsys_free() to ensure that the ctrls and hosts lists are all empty during subsystem release. This helps catch resource leaks. Signed-off-by: Max Gurtovoy Signed-off-by: Keith Busch