Commit 38b91847 authored by Guilherme G. Piccoli's avatar Guilherme G. Piccoli Committed by Kees Cook
Browse files

pstore: Alert on backend write error 



The pstore dump function doesn't alert at all on errors - despite
pstore is usually a last resource and if it fails users won't be
able to read the kernel log, this is not the case for server users
with serial access, for example.

So, let's at least attempt to inform such advanced users on the first
backend writing error detected during the kmsg dump - this is also
very useful for pstore debugging purposes.

Signed-off-by: default avatarGuilherme G. Piccoli <gpiccoli@igalia.com>
Acked-by: default avatarArd Biesheuvel <ardb@kernel.org>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221013210648.137452-2-gpiccoli@igalia.com
parent 7d7eca41

fs/pstore/platform.c

+10 −0
Original line number Diff line number Diff line
@@ -393,6 +393,7 @@ static void pstore_dump(struct kmsg_dumper *dumper, 
	const char	*why;

	unsigned int	part = 1;

	unsigned long	flags = 0;

	int		saved_ret = 0;

	int		ret;



	why = kmsg_dump_reason_str(reason);
@@ -463,12 +464,21 @@ static void pstore_dump(struct kmsg_dumper *dumper, 
		if (ret == 0 && reason == KMSG_DUMP_OOPS) {

			pstore_new_entry = 1;

			pstore_timer_kick();

		} else {

			/* Preserve only the first non-zero returned value. */

			if (!saved_ret)

				saved_ret = ret;

		}



		total += record.size;

		part++;

	}

	spin_unlock_irqrestore(&psinfo->buf_lock, flags);



	if (saved_ret) {

		pr_err_once("backend (%s) writing error (%d)\n", psinfo->name,

			    saved_ret);

	}

}



static struct kmsg_dumper pstore_dumper = {