linux/Documentation
Li RongQing e700f5d156 watchdog: softlockup: panic when lockup duration exceeds N thresholds
The softlockup_panic sysctl is currently a binary option: panic
immediately or never panic on soft lockups.

Panicking on any soft lockup, regardless of duration, can be overly
aggressive for brief stalls that may be caused by legitimate operations. 
Conversely, never panicking may allow severe system hangs to persist
undetected.

Extend softlockup_panic to accept an integer threshold, allowing the
kernel to panic only when the normalized lockup duration exceeds N
watchdog threshold periods.  This provides finer-grained control to
distinguish between transient delays and persistent system failures.

The accepted values are:
- 0: Don't panic (unchanged)
- 1: Panic when duration >= 1 * threshold (20s default, original behavior)
- N > 1: Panic when duration >= N * threshold (e.g., 2 = 40s, 3 = 60s.)

The original behavior is preserved for values 0 and 1, maintaining full
backward compatibility while allowing systems to tolerate brief lockups
while still catching severe, persistent hangs.

[lirongqing@baidu.com: v2]
  Link: https://lkml.kernel.org/r/20251218074300.4080-1-lirongqing@baidu.com
Link: https://lkml.kernel.org/r/20251216074521.2796-1-lirongqing@baidu.com
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Song Liu <song@kernel.org>
Cc: Stanislav Fomichev <sdf@fomichev.me>
Cc: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-20 19:44:20 -08:00
..
ABI treewide: Update email address 2026-01-11 06:09:11 -10:00
accel
accounting
admin-guide watchdog: softlockup: panic when lockup duration exceeds N thresholds 2026-01-20 19:44:20 -08:00
arch treewide: Update email address 2026-01-11 06:09:11 -10:00
block
bpf docs: bpf: map_array: Specify BPF_MAP_TYPE_PERCPU_ARRAY value size limit 2025-11-25 14:32:00 -08:00
cdrom
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dev-tools There are no significant series in this small merge. Please see the 2025-12-13 20:55:12 +12:00
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features Apart from the usual small churn, we have 2025-12-05 16:30:56 -08:00
filesystems filelock: allow lease_managers to dictate what qualifies as a conflict 2025-12-15 15:20:33 +01:00
firmware_class
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gpu Extra drm-misc-next for v6.19-rc1: 2025-12-02 18:09:08 +10:00
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hwmon hwmon: (DS620) Update broken Datasheet URL in driver documentation 2025-12-18 09:50:27 -08:00
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mm Docs/mm/allocation-profiling: describe sysctrl limitations in debug mode 2026-01-20 09:34:26 -08:00
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networking Documentation: net: dsa: mention simple HSR offload helpers 2025-12-01 16:51:55 -08:00
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PCI Documentation: PCI: Amend error recovery doc with pci_save_state() rules 2025-11-24 16:59:10 -06:00
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power More power management updates for 6.19-rc1 2025-12-10 06:29:40 +09:00
process Documentation/process: maintainer-soc: Mark 'make' as commands 2026-01-07 17:47:43 +01:00
RCU
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security Landlock update for v6.19-rc1 2025-12-06 09:52:41 -08:00
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usb
userspace-api media: Documentation: mali-c55: Use v4l2-isp version identifier 2026-01-06 10:14:13 +01:00
virt hyperv-next for v6.19 2025-12-09 06:10:17 +09:00
w1
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.gitignore
.renames.txt
atomic_bitops.txt
atomic_t.txt
Changes
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conf.py
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index.rst
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Makefile docs: makefile: move rustdoc check to the build wrapper 2025-11-29 08:42:53 -07:00
memory-barriers.txt
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subsystem-apis.rst