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Piccoli" To: linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-efi@vger.kernel.org, kernel-dev@igalia.com, kernel@gpiccoli.net, keescook@chromium.org, anton@enomsg.org, ccross@android.com, tony.luck@intel.com, ardb@kernel.org, "Guilherme G. Piccoli" Subject: [PATCH V2 1/3] pstore: Alert on backend write error Date: Thu, 13 Oct 2022 18:06:46 -0300 Message-Id: <20221013210648.137452-2-gpiccoli@igalia.com> X-Mailer: git-send-email 2.38.0 In-Reply-To: <20221013210648.137452-1-gpiccoli@igalia.com> References: <20221013210648.137452-1-gpiccoli@igalia.com> MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1746608485586866808?= X-GMAIL-MSGID: =?utf-8?q?1746608485586866808?= 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: Guilherme G. Piccoli Acked-by: Ard Biesheuvel --- V2: - Show error message late, outside of the critical region (thanks Kees for the idea!). fs/pstore/platform.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c index 06c2c66af332..cbc0b468c1ab 100644 --- a/fs/pstore/platform.c +++ b/fs/pstore/platform.c @@ -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 = {