On Fri 2021-01-08 01:26:06, William Roche wrote: > On 06/01/2021 05:35, Sergey Senozhatsky wrote: > > On (21/01/04 16:15), “William Roche wrote: > >> @@ -271,9 +280,8 @@ void panic(const char *fmt, ...) > >> */ > >> atomic_notifier_call_chain(&panic_notifier_list, 0, buf); > >> > >> - /* Call flush even twice. It tries harder with a single online CPU */ > >> - printk_safe_flush_on_panic(); > >> kmsg_dump(KMSG_DUMP_PANIC); > >> + panic_flush_to_console();
This is wrong. kmsg_dump() flushes the messages into the registered dumpers, e.g. pstore. It handles only messages in the main log buffer. printk_safe_flush_on_panic() must be called before. It moves any pending messages from the temporary per-CPU buffers into the main log buffer so that they are visible for the dumpers. > > Why? > > Here, we are supposed to push the pending messages, as I could verify > that they don't reach the console until the console_unblank(). So I > wanted to push them with panic_flush_to_console() before the possible > upcoming __crash_kexec() call. I do not see how the ordering of printk_safe_flush_on_panic() and kmsg_dump() would change anything for the upcoming __crash_kexec() call. Best Regards, Petr
