This series introduces a family of helper functions to manage panic state and
updates existing code to use them.
Before this series, panic state helpers were scattered and inconsistent. For
example, panic_in_progress() was defined in printk/printk.c, not in panic.c or
panic.h. As a result, developers had to look in unexpected places to understand
or re-use panic state logic. Other checks were open- coded, duplicating logic
across panic, crash, and watchdog paths.
The new helpers centralize the functionality in panic.c/panic.h:
- panic_try_start()
- panic_reset()
- panic_in_progress()
- panic_on_this_cpu()
- panic_on_other_cpu()
Patches 1–8 add the helpers and convert panic/crash and printk/nbcon code to
use them.
Patch 9 fixes a bug in the watchdog subsystem by skipping checks when a panic
is in progress, avoiding interference with the panic CPU.
Together, this makes panic state handling simpler, more discoverable, and more
robust.
--
Changes from v1:
- The commit messages have been re-formatted based on Baoquan He's
suggestions.
- The panic_in_progress() check has been moved to be the first check in
watchdog_overflow_callback(), as suggested by Yury Norov.
Link to v1:
https://lore.kernel.org/all/20250820091702.512524-1-wangjinchao...@gmail.com/
Jinchao Wang (9):
panic: Introduce helper functions for panic state
fbdev: Use panic_in_progress() helper
crash_core: use panic_try_start() in crash_kexec()
panic: use panic_try_start() in nmi_panic()
panic: use panic_try_start() in vpanic()
printk/nbcon: use panic_on_this_cpu() helper
panic/printk: replace this_cpu_in_panic() with panic_on_this_cpu()
panic/printk: replace other_cpu_in_panic() with panic_on_other_cpu()
watchdog: skip checks when panic is in progress
drivers/video/fbdev/core/fbcon.c | 9 +---
include/linux/panic.h | 6 +++
include/linux/printk.h | 2 -
kernel/crash_core.c | 15 ++-----
kernel/panic.c | 71 +++++++++++++++++++++++++------
kernel/printk/internal.h | 1 -
kernel/printk/nbcon.c | 14 +++---
kernel/printk/printk.c | 37 +++-------------
kernel/printk/printk_ringbuffer.c | 2 +-
kernel/watchdog.c | 6 +++
kernel/watchdog_perf.c | 4 ++
lib/dump_stack.c | 2 +-
12 files changed, 91 insertions(+), 78 deletions(-)
--
2.43.0
