On 01/14/22 at 03:30pm, Guilherme G. Piccoli wrote:
......
> .../admin-guide/kernel-parameters.txt | 4 ++++
> kernel/panic.c | 22 ++++++++++++++-----
> 2 files changed, 21 insertions(+), 5 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index a069d8fe2fee..0f5cbe141bfd 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -3727,6 +3727,10 @@
> bit 4: print ftrace buffer
> bit 5: print all printk messages in buffer
> bit 6: print all CPUs backtrace (if available in the arch)
> + *Be aware* that this option may print a _lot_ of lines,
> + so there are risks of losing older messages in the log.
> + Use this option carefully, maybe worth to setup a
> + bigger log buffer with "log_buf_len" along with this.
>
> panic_on_taint= Bitmask for conditionally calling panic() in add_taint()
> Format: <hex>[,nousertaint]
> diff --git a/kernel/panic.c b/kernel/panic.c
> index 41ecf9ab824a..4ae712665f75 100644
> --- a/kernel/panic.c
> +++ b/kernel/panic.c
> @@ -148,10 +148,13 @@ void nmi_panic(struct pt_regs *regs, const char *msg)
> }
> EXPORT_SYMBOL(nmi_panic);
>
> -static void panic_print_sys_info(void)
> +static void panic_print_sys_info(bool after_kmsg_dumpers)
> {
> - if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG)
> - console_flush_on_panic(CONSOLE_REPLAY_ALL);
> + if (after_kmsg_dumpers) {
> + if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG)
> + console_flush_on_panic(CONSOLE_REPLAY_ALL);
> + return;
> + }
>
> if (panic_print & PANIC_PRINT_ALL_CPU_BT)
> trigger_all_cpu_backtrace();
> @@ -249,7 +252,7 @@ void panic(const char *fmt, ...)
> * show some extra information on kernel log if it was set...
> */
> if (kexec_crash_loaded())
> - panic_print_sys_info();
> + panic_print_sys_info(false);
Patch can'e be applied on the latest code of linus's tree, can you tell
which branch your code are based on?
>
> /*
> * If we have crashed and we have a crash kernel loaded let it handle
> @@ -283,6 +286,15 @@ void panic(const char *fmt, ...)
> */
> atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
>
> + /*
> + * If kexec_crash_loaded() is true and we still reach this point,
> + * kernel would double print the information from panic_print; so
> + * let's guard against that possibility (it happens if kdump users
> + * also set crash_kexec_post_notifiers in the command-line).
> + */
> + if (!kexec_crash_loaded())
> + panic_print_sys_info(false);
> +
> kmsg_dump(KMSG_DUMP_PANIC);
>
> /*
> @@ -313,7 +325,7 @@ void panic(const char *fmt, ...)
> debug_locks_off();
> console_flush_on_panic(CONSOLE_FLUSH_PENDING);
>
> - panic_print_sys_info();
> + panic_print_sys_info(true);
>
> if (!panic_blink)
> panic_blink = no_blink;
> --
> 2.34.1
>
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