linux/kernel/trace
Yu Kuai dfe48ea179 blk-mq: use NOIO context to prevent deadlock during debugfs creation
Creating debugfs entries can trigger fs reclaim, which can enter back
into the block layer request_queue. This can cause deadlock if the
queue is frozen.

Previously, a WARN_ON_ONCE check was used in debugfs_create_files()
to detect this condition, but it was racy since the queue can be frozen
from another context at any time.

Introduce blk_debugfs_lock()/blk_debugfs_unlock() helpers that combine
the debugfs_mutex with memalloc_noio_save()/restore() to prevent fs
reclaim from triggering block I/O. Also add blk_debugfs_lock_nomemsave()
and blk_debugfs_unlock_nomemrestore() variants for callers that don't
need NOIO protection (e.g., debugfs removal or read-only operations).

Replace all raw debugfs_mutex lock/unlock pairs with these helpers,
using the _nomemsave/_nomemrestore variants where appropriate.

Reported-by: Yi Zhang <yi.zhang@redhat.com>
Closes: https://lore.kernel.org/all/CAHj4cs9gNKEYAPagD9JADfO5UH+OiCr4P7OO2wjpfOYeM-RV=A@mail.gmail.com/
Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Closes: https://lore.kernel.org/all/aYWQR7CtYdk3K39g@shinmob/
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Yu Kuai <yukuai@fnnas.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-02-16 10:47:25 -07:00
..
rv rv: Convert to use __free 2025-12-02 07:28:32 +01:00
blktrace.c blk-mq: use NOIO context to prevent deadlock during debugfs creation 2026-02-16 10:47:25 -07:00
bpf_trace.c bpf: support fsession for bpf_session_is_return 2026-01-24 18:49:36 -08:00
bpf_trace.h tracing/treewide: Remove second parameter of __assign_str() 2024-05-22 20:14:47 -04:00
error_report-traces.c
fgraph.c tracing: Fix typo in fpgraph.c 2025-12-05 15:43:39 -05:00
fprobe.c tracing fixes for v6.19: 2025-12-06 13:49:40 -08:00
ftrace.c bpf-next-7.0 2026-02-10 11:26:21 -08:00
ftrace_internal.h function_graph: Make fgraph_update_pid_func() a stub for !DYNAMIC_FTRACE 2024-06-10 18:08:23 -04:00
Kconfig bpf,x86: Use single ftrace_ops for direct calls 2026-01-28 11:44:59 -08:00
kprobe_event_gen_test.c tracing: Fix wrong return in kprobe_event_gen_test.c 2023-03-19 12:20:48 -04:00
Makefile ftrace: Allow tracing of some of the tracing code 2025-11-26 15:13:30 -05:00
pid_list.c trace/pid_list: optimize pid_list->lock contention 2025-11-13 15:15:54 -05:00
pid_list.h trace/pid_list: optimize pid_list->lock contention 2025-11-13 15:15:54 -05:00
power-traces.c PM: cpufreq: powernv/tracing: Move powernv_throttle trace event 2025-07-21 16:40:56 -04:00
preemptirq_delay_test.c kernel: trace: preemptirq_delay_test: use offstack cpu mask 2025-07-08 18:17:38 -04:00
rethook.c rethook: honor CONFIG_FTRACE_VALIDATE_RCU_IS_WATCHING in rethook_try_get() 2024-05-01 23:18:48 +09:00
ring_buffer.c ring-buffer: Avoid softlockup in ring_buffer_resize() during memory free 2026-01-07 14:52:22 -05:00
ring_buffer_benchmark.c tracing: Fix typo in ring_buffer_benchmark.c 2025-12-05 15:43:40 -05:00
rpm-traces.c
synth_event_gen_test.c tracing / synthetic: Disable events after testing in synth_event_gen_test_init() 2023-12-21 10:04:45 -05:00
trace.c tracing: Avoid possible signed 64-bit truncation 2026-01-23 13:34:30 -05:00
trace.h tracing: Fix ftrace event field alignments 2026-02-05 09:47:11 -05:00
trace_benchmark.c tracing: Improve benchmark test performance by using do_div() 2024-05-13 20:00:57 -04:00
trace_benchmark.h
trace_boot.c tracing: Allow creating instances with specified system events 2023-12-18 23:14:16 -05:00
trace_branch.c tracing: branch: Use trace_tracing_is_on_cpu() instead of "disabled" field 2025-05-09 15:19:10 -04:00
trace_btf.c tracing/probes: Fix to search structure fields correctly 2024-02-17 21:25:42 +09:00
trace_btf.h tracing/probes: Add a function to search a member of a struct/union 2023-08-23 09:40:16 +09:00
trace_clock.c tracing: Use atomic64_inc_return() in trace_clock_counter() 2024-10-09 19:59:49 -04:00
trace_dynevent.c tracing: Report wrong dynamic event command 2025-11-10 19:26:14 -05:00
trace_dynevent.h tracing: probes: Fix a possible race in trace_probe_log APIs 2025-05-13 22:23:34 +09:00
trace_entries.h tracing: Fix ftrace event field alignments 2026-02-05 09:47:11 -05:00
trace_eprobe.c Probes for v6.19 2025-12-05 10:55:47 -08:00
trace_event_perf.c perf: Remove unnecessary parameter of security check 2025-02-26 14:13:58 -05:00
trace_events.c tracing: Drop unneeded assignment to soft_mode 2026-01-07 14:52:22 -05:00
trace_events_filter.c tracing: Fix typo in trace_events_filter.c 2025-12-05 15:43:40 -05:00
trace_events_filter_test.h
trace_events_hist.c tracing: Fix crash on synthetic stacktrace field usage 2026-01-23 13:34:21 -05:00
trace_events_inject.c tracing: Have format file honor EVENT_FILE_FL_FREED 2024-08-07 18:12:46 -04:00
trace_events_synth.c tracing: Fix crash on synthetic stacktrace field usage 2026-01-23 13:34:21 -05:00
trace_events_trigger.c tracing: Fix typo in trace_events_trigger.c 2025-12-05 15:43:41 -05:00
trace_events_user.c tracing: Fix multiple typos in trace_events_user.c 2025-12-05 15:43:41 -05:00
trace_export.c tracing: Fix ftrace event field alignments 2026-02-05 09:47:11 -05:00
trace_fprobe.c tracing updates for v6.19: 2025-12-05 09:51:37 -08:00
trace_functions.c tracing: Have function tracer define options per instance 2025-11-12 09:59:54 -05:00
trace_functions_graph.c function_graph: Fix args pointer mismatch in print_graph_retval() 2026-01-23 13:34:38 -05:00
trace_hwlat.c tracing: Replace opencoded cpumask_next_wrap() in move_to_next_cpu() 2025-07-08 18:17:29 -04:00
trace_irqsoff.c tracing: Allow tracer to add more than 32 options 2025-11-04 21:44:00 +09:00
trace_kdb.c tracing: Allow tracer to add more than 32 options 2025-11-04 21:44:00 +09:00
trace_kprobe.c tracing: Allow tracer to add more than 32 options 2025-11-04 21:44:00 +09:00
trace_kprobe_selftest.c tracing: arm64: Avoid missing-prototype warnings 2023-07-12 12:06:04 -04:00
trace_kprobe_selftest.h
trace_mmiotrace.c tracing/mmiotrace: Remove reference to unused per CPU data pointer 2025-05-08 09:36:09 -04:00
trace_nop.c
trace_osnoise.c tracing: Fix multiple typos in trace_osnoise.c 2025-12-05 15:43:41 -05:00
trace_output.c tracing updates for v6.19: 2025-12-05 09:51:37 -08:00
trace_output.h tracing: Allow tracer to add more than 32 options 2025-11-04 21:44:00 +09:00
trace_preemptirq.c tracing: Fix archs that still call tracepoints without RCU watching 2024-12-05 09:28:58 -05:00
trace_printk.c
trace_probe.c tracing fixes for v6.19: 2025-12-06 13:49:40 -08:00
trace_probe.h tracing: probes: Use __free() for trace_probe_log 2025-11-01 01:10:28 +09:00
trace_probe_kernel.h tracing/probes: Fix to record 0-length data_loc in fetch_store_string*() if fails 2023-07-14 17:04:58 +09:00
trace_probe_tmpl.h tracing/fprobe: Enable fprobe events with CONFIG_DYNAMIC_FTRACE_WITH_ARGS 2024-12-26 10:50:04 -05:00
trace_recursion_record.c
trace_sched_switch.c tracing: Ensure optimized hashing works 2025-09-30 17:27:58 -04:00
trace_sched_wakeup.c tracing: Allow tracer to add more than 32 options 2025-11-04 21:44:00 +09:00
trace_selftest.c fgraph: Pass ftrace_regs to retfunc 2024-12-26 10:50:03 -05:00
trace_selftest_dynamic.c
trace_seq.c tracing: Fix typo in trace_seq.c 2025-12-05 15:43:41 -05:00
trace_stack.c tracing updates for v6.16: 2025-05-29 21:04:36 -07:00
trace_stat.c tracing: Switch trace_stat.c code over to use guard() 2024-12-26 10:38:37 -05:00
trace_stat.h
trace_synth.h
trace_syscalls.c tracing: Hide __NR_utimensat and _NR_mq_timedsend when not defined 2025-11-10 14:23:53 -05:00
trace_uprobe.c tracing: uprobe: eprobes: Allocate traceprobe_parse_context per probe 2025-11-01 01:10:29 +09:00
tracing_map.c tracing: Use vmalloc_array() to improve code 2025-09-23 09:31:58 -04:00
tracing_map.h tracing: Remove unused extern declaration tracing_map_set_field_descr() 2023-07-23 11:08:14 -04:00