On (04/01/19 18:48), Feng Tang wrote:
> diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
> index 1fd45a8..58d9580 100644
> --- a/arch/powerpc/kernel/traps.c
> +++ b/arch/powerpc/kernel/traps.c
> @@ -179,7 +179,7 @@ extern void panic_flush_kmsg_end(void)
> kmsg_dump(KMSG_DUMP_PANIC);
> bust_spinlocks(0);
> debug_locks_off();
> - console_flush_on_panic();
> + console_flush_on_panic(false);
> }
[..]
> @@ -277,7 +277,7 @@ void panic(const char *fmt, ...)
> * panic() is not being callled from OOPS.
> */
> debug_locks_off();
> - console_flush_on_panic();
> + console_flush_on_panic(false);
[..]
> -void console_flush_on_panic(void)
> +void console_flush_on_panic(bool flush_all)
> {
> /*
> * If someone else is holding the console lock, trylock will fail
> @@ -2539,6 +2540,12 @@ void console_flush_on_panic(void)
> */
> console_trylock();
> console_may_schedule = 0;
> +
> + /* User may want to see all the printk messages on panic */
> + if (flush_all) {
> + console_seq = log_first_seq;
> + console_idx = log_first_idx;
> + }
> console_unlock();
So my first thought was - let's not add a `bool flag', but instead add
an `enum' with clear flag names, e.g. DUMP_ALL/DUMP_PENDING, etc. Something
similar to what ftrace_dump(DUMP_ALL) does. And we already have panic_print
bit-mask and panic_print_sys_info(), which controls what we print when in
panic. So we can move console_flush_on_panic() to panic_print_sys_info()
and handle different types of console_flush_on_panic() there:
---
diff --git a/kernel/panic.c b/kernel/panic.c
index 0ae0d7332f12..e142faaebbcd 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -134,6 +134,11 @@ EXPORT_SYMBOL(nmi_panic);
static void panic_print_sys_info(void)
{
+ if (panic_print & PANIC_PRINT_REPLAY_LOGBUF)
+ console_flush_on_panic(DUMP_ALL);
+ else
+ console_flush_on_panic(DUMP_PENDING);
+
if (panic_print & PANIC_PRINT_TASK_INFO)
show_state();
@@ -277,7 +282,6 @@ void panic(const char *fmt, ...)
* panic() is not being callled from OOPS.
*/
debug_locks_off();
- console_flush_on_panic();
panic_print_sys_info();
---
After looking at this more - DUMP_ALL/DUMP_PENDING clearly depend
on panic_print. So... May be we can move panic_print_sys_info() to
printk.c, and for PANIC_PRINT_REPLAY_LOGBUF case just reset console
seq/idx (console seq/idx are internal to printk) before we
flush_on_panic. This way we would not need to modify
console_flush_on_panic() prototype at all.
Let's hear from people.
-ss
