kernel/drivers/nvme/host/multipath.c, branch master

nvme-multipath: fix leak on try_module_get failure

2026-02-27T15:35:15Z

We need to fall back to the synchronous removal if we can't get a reference on the module needed for the deferred removal. Fixes: 62188639ec16 ("nvme-multipath: introduce delayed removal of the multipath head node") Reviewed-by: Nilay Shroff Reviewed-by: John Garry Reviewed-by: Christoph Hellwig Signed-off-by: Keith Busch

nvme: correct comment about nvme_ns_remove()

2026-02-06T15:59:25Z

The comment in nvme_mpath_remove_disk() references nvme_remove_ns(), which should be nvme_ns_remove(). Reviewed-by: Christoph Hellwig Signed-off-by: John Garry Signed-off-by: Keith Busch

Merge tag 'for-6.19/block-20251201' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux

2025-12-04T03:26:18Z

Pull block updates from Jens Axboe: - Fix head insertion for mq-deadline, a regression from when priority support was added - Series simplifying and improving the ublk user copy code - Various ublk related cleanups - Fixup REQ_NOWAIT handling in loop/zloop, clearing NOWAIT when the request is punted to a thread for handling - Merge and then later revert loop dio nowait support, as it ended up causing excessive stack usage for when the inline issue code needs to dip back into the full file system code - Improve auto integrity code, making it less deadlock prone - Speedup polled IO handling, but manually managing the hctx lookups - Fixes for blk-throttle for SSD devices - Small series with fixes for the S390 dasd driver - Add support for caching zones, avoiding unnecessary report zone queries - MD pull requests via Yu: - fix null-ptr-dereference regression for dm-raid0 - fix IO hang for raid5 when array is broken with IO inflight - remove legacy 1s delay to speed up system shutdown - change maintainer's email address - data can be lost if array is created with different lbs devices, fix this problem and record lbs of the array in metadata - fix rcu protection for md_thread - fix mddev kobject lifetime regression - enable atomic writes for md-linear - some cleanups - bcache updates via Coly - remove useless discard and cache device code - improve usage of per-cpu workqueues - Reorganize the IO scheduler switching code, fixing some lockdep reports as well - Improve the block layer P2P DMA support - Add support to the block tracing code for zoned devices - Segment calculation improves, and memory alignment flexibility improvements - Set of prep and cleanups patches for ublk batching support. The actual batching hasn't been added yet, but helps shrink down the workload of getting that patchset ready for 6.20 - Fix for how the ps3 block driver handles segments offsets - Improve how block plugging handles batch tag allocations - nbd fixes for use-after-free of the configuration on device clear/put - Set of improvements and fixes for zloop - Add Damien as maintainer of the block zoned device code handling - Various other fixes and cleanups * tag 'for-6.19/block-20251201' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: (162 commits) block/rnbd: correct all kernel-doc complaints blk-mq: use queue_hctx in blk_mq_map_queue_type md: remove legacy 1s delay in md_notify_reboot md/raid5: fix IO hang when array is broken with IO inflight md: warn about updating super block failure md/raid0: fix NULL pointer dereference in create_strip_zones() for dm-raid sbitmap: fix all kernel-doc warnings ublk: add helper of __ublk_fetch() ublk: pass const pointer to ublk_queue_is_zoned() ublk: refactor auto buffer register in ublk_dispatch_req() ublk: add `union ublk_io_buf` with improved naming ublk: add parameter `struct io_uring_cmd *` to ublk_prep_auto_buf_reg() kfifo: add kfifo_alloc_node() helper for NUMA awareness blk-mq: fix potential uaf for 'queue_hw_ctx' blk-mq: use array manage hctx map instead of xarray ublk: prevent invalid access with DEBUG s390/dasd: Use scnprintf() instead of sprintf() s390/dasd: Move device name formatting into separate function s390/dasd: Remove unnecessary debugfs_create() return checks s390/dasd: Fix gendisk parent after copy pair swap ...

nvme-multipath: fix lockdep WARN due to partition scan work

2025-11-17T16:08:00Z

Blktests test cases nvme/014, 057 and 058 fail occasionally due to a lockdep WARN. As reported in the Closes tag URL, the WARN indicates that a deadlock can happen due to the dependency among disk->open_mutex, kblockd workqueue completion and partition_scan_work completion. To avoid the lockdep WARN and the potential deadlock, cut the dependency by running the partition_scan_work not by kblockd workqueue but by nvme_wq. Reported-by: Yi Zhang Closes: https://lore.kernel.org/linux-block/CAHj4cs8mJ+R_GmQm9R8ebResKAWUE8kF5+_WVg0v8zndmqd6BQ@mail.gmail.com/ Link: https://lore.kernel.org/linux-block/oeyzci6ffshpukpfqgztsdeke5ost5hzsuz4rrsjfmvpqcevax@5nhnwbkzbrpa/ Fixes: 1f021341eef4 ("nvme-multipath: defer partition scanning") Signed-off-by: Shin'ichiro Kawasaki Reviewed-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Signed-off-by: Keith Busch

block: introduce disk_report_zone()

2025-11-05T15:07:21Z

Commit b76b840fd933 ("dm: Fix dm-zoned-reclaim zone write pointer alignment") introduced an indirect call for the callback function of a report zones executed with blkdev_report_zones(). This is necessary so that the function disk_zone_wplug_sync_wp_offset() can be called to refresh a zone write plug zone write pointer offset after a write error. However, this solution makes following the path of a zone information harder to understand. Clean this up by introducing the new blk_report_zones_args structure to define a zone report callback and its private data and introduce the helper function disk_report_zone() which calls both disk_zone_wplug_sync_wp_offset() and the zone report user callback function for all zones of a zone report. This helper function must be called by all block device drivers that implement the report zones block operation in order to correctly report a zone information. All block device drivers supporting the report_zones block operation are updated to use this new scheme. Signed-off-by: Damien Le Moal Reviewed-by: Christoph Hellwig Reviewed-by: Johannes Thumshirn Reviewed-by: Chaitanya Kulkarni Reviewed-by: Hannes Reinecke Reviewed-by: Martin K. Petersen Signed-off-by: Jens Axboe

nvme-multipath: Skip nr_active increments in RETRY disposition

2025-10-09T15:07:01Z

For queue-depth I/O policy, this patch fixes unbalanced I/Os across nvme multipaths. Issue Description: The RETRY disposition incorrectly increments ns->ctrl->nr_active counter and reinitializes iostat start-time. In such cases nr_active counter never goes back to zero until that path disconnects and reconnects. Such a path is not chosen for new I/Os if multiple RETRY cases on a given a path cause its queue-depth counter to be artificially higher compared to other paths. This leads to unbalanced I/Os across paths. The patch skips incrementing nr_active if NVME_MPATH_CNT_ACTIVE is already set. And it skips restarting io stats if NVME_MPATH_IO_STATS is already set. base-commit: e989a3da2d371a4b6597ee8dee5c72e407b4db7a Fixes: d4d957b53d91eeb ("nvme-multipath: support io stats on the mpath device") Signed-off-by: Amit Chaudhary Reviewed-by: Randy Jennings Signed-off-by: Keith Busch

Merge tag 'block-6.16-20250704' of git://git.kernel.dk/linux

2025-07-04T16:33:59Z

Pull block fixes from Jens Axboe: - NVMe fixes via Christoph: - fix incorrect cdw15 value in passthru error logging (Alok Tiwari) - fix memory leak of bio integrity in nvmet (Dmitry Bogdanov) - refresh visible attrs after being checked (Eugen Hristev) - fix suspicious RCU usage warning in the multipath code (Geliang Tang) - correctly account for namespace head reference counter (Nilay Shroff) - Fix for a regression introduced in ublk in this cycle, where it would attempt to queue a canceled request. - brd RCU sleeping fix, also introduced in this cycle. Bare bones fix, should be improved upon for the next release. * tag 'block-6.16-20250704' of git://git.kernel.dk/linux: brd: fix sleeping function called from invalid context in brd_insert_page() ublk: don't queue request if the associated uring_cmd is canceled nvme-multipath: fix suspicious RCU usage warning nvme-pci: refresh visible attrs after being checked nvmet: fix memory leak of bio integrity nvme: correctly account for namespace head reference counter nvme: Fix incorrect cdw15 value in passthru error logging

nvme-multipath: fix suspicious RCU usage warning

2025-07-01T06:17:02Z

When I run the NVME over TCP test in virtme-ng, I get the following "suspicious RCU usage" warning in nvme_mpath_add_sysfs_link(): ''' [ 5.024557][ T44] nvmet: Created nvm controller 1 for subsystem nqn.2025-06.org.nvmexpress.mptcp for NQN nqn.2014-08.org.nvmexpress:uuid:f7f6b5e0-ff97-4894-98ac-c85309e0bc77. [ 5.027401][ T183] nvme nvme0: creating 2 I/O queues. [ 5.029017][ T183] nvme nvme0: mapped 2/0/0 default/read/poll queues. [ 5.032587][ T183] nvme nvme0: new ctrl: NQN "nqn.2025-06.org.nvmexpress.mptcp", addr 127.0.0.1:4420, hostnqn: nqn.2014-08.org.nvmexpress:uuid:f7f6b5e0-ff97-4894-98ac-c85309e0bc77 [ 5.042214][ T25] [ 5.042440][ T25] ============================= [ 5.042579][ T25] WARNING: suspicious RCU usage [ 5.042705][ T25] 6.16.0-rc3+ #23 Not tainted [ 5.042812][ T25] ----------------------------- [ 5.042934][ T25] drivers/nvme/host/multipath.c:1203 RCU-list traversed in non-reader section!! [ 5.043111][ T25] [ 5.043111][ T25] other info that might help us debug this: [ 5.043111][ T25] [ 5.043341][ T25] [ 5.043341][ T25] rcu_scheduler_active = 2, debug_locks = 1 [ 5.043502][ T25] 3 locks held by kworker/u9:0/25: [ 5.043615][ T25] #0: ffff888008730948 ((wq_completion)async){+.+.}-{0:0}, at: process_one_work+0x7ed/0x1350 [ 5.043830][ T25] #1: ffffc900001afd40 ((work_completion)(&entry->work)){+.+.}-{0:0}, at: process_one_work+0xcf3/0x1350 [ 5.044084][ T25] #2: ffff888013ee0020 (&head->srcu){.+.+}-{0:0}, at: nvme_mpath_add_sysfs_link.part.0+0xb4/0x3a0 [ 5.044300][ T25] [ 5.044300][ T25] stack backtrace: [ 5.044439][ T25] CPU: 0 UID: 0 PID: 25 Comm: kworker/u9:0 Not tainted 6.16.0-rc3+ #23 PREEMPT(full) [ 5.044441][ T25] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 5.044442][ T25] Workqueue: async async_run_entry_fn [ 5.044445][ T25] Call Trace: [ 5.044446][ T25] [ 5.044449][ T25] dump_stack_lvl+0x6f/0xb0 [ 5.044453][ T25] lockdep_rcu_suspicious.cold+0x4f/0xb1 [ 5.044457][ T25] nvme_mpath_add_sysfs_link.part.0+0x2fb/0x3a0 [ 5.044459][ T25] ? queue_work_on+0x90/0xf0 [ 5.044461][ T25] ? lockdep_hardirqs_on+0x78/0x110 [ 5.044466][ T25] nvme_mpath_set_live+0x1e9/0x4f0 [ 5.044470][ T25] nvme_mpath_add_disk+0x240/0x2f0 [ 5.044472][ T25] ? __pfx_nvme_mpath_add_disk+0x10/0x10 [ 5.044475][ T25] ? add_disk_fwnode+0x361/0x580 [ 5.044480][ T25] nvme_alloc_ns+0x81c/0x17c0 [ 5.044483][ T25] ? kasan_quarantine_put+0x104/0x240 [ 5.044487][ T25] ? __pfx_nvme_alloc_ns+0x10/0x10 [ 5.044495][ T25] ? __pfx_nvme_find_get_ns+0x10/0x10 [ 5.044496][ T25] ? rcu_read_lock_any_held+0x45/0xa0 [ 5.044498][ T25] ? validate_chain+0x232/0x4f0 [ 5.044503][ T25] nvme_scan_ns+0x4c8/0x810 [ 5.044506][ T25] ? __pfx_nvme_scan_ns+0x10/0x10 [ 5.044508][ T25] ? find_held_lock+0x2b/0x80 [ 5.044512][ T25] ? ktime_get+0x16d/0x220 [ 5.044517][ T25] ? kvm_clock_get_cycles+0x18/0x30 [ 5.044520][ T25] ? __pfx_nvme_scan_ns_async+0x10/0x10 [ 5.044522][ T25] async_run_entry_fn+0x97/0x560 [ 5.044523][ T25] ? rcu_is_watching+0x12/0xc0 [ 5.044526][ T25] process_one_work+0xd3c/0x1350 [ 5.044532][ T25] ? __pfx_process_one_work+0x10/0x10 [ 5.044536][ T25] ? assign_work+0x16c/0x240 [ 5.044539][ T25] worker_thread+0x4da/0xd50 [ 5.044545][ T25] ? __pfx_worker_thread+0x10/0x10 [ 5.044546][ T25] kthread+0x356/0x5c0 [ 5.044548][ T25] ? __pfx_kthread+0x10/0x10 [ 5.044549][ T25] ? ret_from_fork+0x1b/0x2e0 [ 5.044552][ T25] ? __lock_release.isra.0+0x5d/0x180 [ 5.044553][ T25] ? ret_from_fork+0x1b/0x2e0 [ 5.044555][ T25] ? rcu_is_watching+0x12/0xc0 [ 5.044557][ T25] ? __pfx_kthread+0x10/0x10 [ 5.044559][ T25] ret_from_fork+0x218/0x2e0 [ 5.044561][ T25] ? __pfx_kthread+0x10/0x10 [ 5.044562][ T25] ret_from_fork_asm+0x1a/0x30 [ 5.044570][ T25] ''' This patch uses sleepable RCU version of helper list_for_each_entry_srcu() instead of list_for_each_entry_rcu() to fix it. Fixes: 4dbd2b2ebe4c ("nvme-multipath: Add visibility for round-robin io-policy") Signed-off-by: Geliang Tang Reviewed-by: Keith Busch Reviewed-by: Hannes Reinecke Reviewed-by: Nilay Shroff Signed-off-by: Christoph Hellwig

nvme: correctly account for namespace head reference counter

2025-06-30T06:31:49Z

The blktests nvme/058 manifests an issue where the NVMe subsystem kobject entry remains stale in sysfs, causing a failure during subsequent NVMe module reloads[1]. Specifically, when attempting to register a new NVMe subsystem, the driver encounters a kobejct name collision because a stale kobject still exists. Though, please note that nvme/058 doesn't report any failure and test case passes and it's only during subsequent NVMe module reloads, the stale nvme sub- system kobject entry in sysfs causes the observed symptom[1]. This issue stems from an imbalance in the get/put usage of the namespace head (nshead) reference counter. The nshead holds a reference to the associated NVMe subsystem. If the nshead reference is not properly released, it prevents the cleanup of the subsystem's kobject, leaving nvme subsystem stale entry behind in sysfs. During the failure case, the last namespace path referencing a nshead is removed, but the nshead reference was not released. This occurs because the release logic currently only puts the nshead reference when its state is LIVE. However, in configurations where ANA (Asymmetric Namespace Access) is enabled, a namespace may be associated with an ANA state that is neither optimized nor non-optimized. In this case, the nshead may never transition to LIVE, and the corresponding nshead reference is then never dropped. In fact nvme/058 associates some of nvme namespaces to an inaccessible ANA state and with that nshead is created but it's state is not transitioned to LIVE. So the current logic would then causes nshead reference to be leaked for non-LIVE states. Another scenario, during namespace allocation, the driver first allocates a nshead and then issues an Identify Namespace command. If this command fails — which can happen in tests like nvme/058 that rapidly enables and disables namespaces — we must release the reference to the newly allocated nshead. However this reference release is currently missing in the failure, causing a nshead reference leak. To fix this, we now unconditionally release the nshead reference when the last nvme path referencing to the nshead is removed, regardless of the head’s state. Also during identify namespace failure case we now properly release the nshead reference. So this ensures proper cleanup of the nshead, and consequently, the NVMe subsystem and its associated kobject. This change prevents stale kobject entries from lingering in sysfs and eliminates the module reload failures observed just after running nvme/058. [1] https://lore.kernel.org/all/CAHj4cs8fOBS-eSjsd5LUBzy7faKXJtgLkCN+mDy_-ezCLLLq+Q@mail.gmail.com/ Reported-by: yi.zhang@redhat.com Closes: https://lore.kernel.org/all/CAHj4cs8fOBS-eSjsd5LUBzy7faKXJtgLkCN+mDy_-ezCLLLq+Q@mail.gmail.com/ Fixes: 62188639ec16 ("nvme-multipath: introduce delayed removal of the multipath head node") Tested-by: yi.zhang@redhat.com Signed-off-by: Nilay Shroff Reviewed-by: Hannes Reinecke Signed-off-by: Christoph Hellwig

Merge tag 'block-6.16-20250626' of git://git.kernel.dk/linux

2025-06-27T16:02:33Z

Pull block fixes from Jens Axboe: - Fixes for ublk: - fix C++ narrowing warnings in the uapi header - update/improve UBLK_F_SUPPORT_ZERO_COPY comment in uapi header - fix for the ublk ->queue_rqs() implementation, limiting a batch to just the specific task AND ring - ublk_get_data() error handling fix - sanity check more arguments in ublk_ctrl_add_dev() - selftest addition - NVMe pull request via Christoph: - reset delayed remove_work after reconnect - fix atomic write size validation - Fix for a warning introduced in bdev_count_inflight_rw() in this merge window * tag 'block-6.16-20250626' of git://git.kernel.dk/linux: block: fix false warning in bdev_count_inflight_rw() ublk: sanity check add_dev input for underflow nvme: fix atomic write size validation nvme: refactor the atomic write unit detection nvme: reset delayed remove_work after reconnect ublk: setup ublk_io correctly in case of ublk_get_data() failure ublk: update UBLK_F_SUPPORT_ZERO_COPY comment in UAPI header ublk: fix narrowing warnings in UAPI header selftests: ublk: don't take same backing file for more than one ublk devices ublk: build batch from IOs in same io_ring_ctx and io task