Re: [RFC PATCH v2 1/5] panic, sys_info: Fix duplicate and dropped all-CPU backtraces in panic

[sashiko-bot@kernel.org]

> When sys_info() was factored out of kernel/panic.c by
> commit b76e89e50fc3 ("panic: generalize panic_print's function to show
> sys info"), __sys_info() gained an unconditional call to
> trigger_all_cpu_backtrace() when SYS_INFO_ALL_BT is set, while
> panic_other_cpus_shutdown() retained its own call to
> panic_trigger_all_cpu_backtrace().
> 
> This causes two problems during a kernel panic:
> 
>     1.  vpanic() invokes panic_trigger_all_cpu_backtrace() inside
>         panic_other_cpus_shutdown() before stopping secondary CPUs, and
>         then invokes trigger_all_cpu_backtrace() a second time inside
>         sys_info(panic_print) after secondary CPUs have already been
>         shut down, stalling for up to 10 seconds waiting for offline
>         CPUs to respond to NMIs. Furthermore, if SYS_INFO_ALL_BT is
> [ ... ]
> panic_try_start(), and route SYS_INFO_ALL_BT in __sys_info()
> through panic_trigger_all_cpu_backtrace() on the panicking CPU.
> 
> Fixes: b76e89e50fc3 ("panic: generalize panic_print's function to show sys info")
> Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>

Sashiko has reviewed this patch and found no issues.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261103024453.922373-1-atomlin@atomlin.com?part=1