From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Osipenko Date: Wed, 27 Oct 2021 21:16:35 +0000 Subject: [PATCH v2 05/45] reboot: Warn if restart handler has duplicated priority Message-Id: <20211027211715.12671-6-digetx@gmail.com> List-Id: References: <20211027211715.12671-1-digetx@gmail.com> In-Reply-To: <20211027211715.12671-1-digetx@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Thierry Reding , Jonathan Hunter , Lee Jones , "Rafael J . Wysocki" , Mark Brown , Andrew Morton , Guenter Roeck , Russell King , Daniel Lezcano , Andy Shevchenko , Ulf Hansson Cc: Catalin Marinas , Will Deacon , Guo Ren , Geert Uytterhoeven , Greg Ungerer , Joshua Thompson , Thomas Bogendoerfer , Nick Hu , Greentime Hu , Vincent Chen , "James E.J. Bottomley" , Helge Deller , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Paul Walmsley , Palmer Dabbelt , Albert Ou , Yoshinori Sato , Rich Felker , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Boris Ostrovsky , Juergen Gross , Stefano Stabellini , Len Brown , Santosh Shilimkar , Krzysztof Kozlowski , Linus Walleij , Chen-Yu Tsai , =?UTF-8?q?Jonathan=20Neusch=C3=A4fer?= , Tony Lindgren , Liam Girdwood , Philipp Zabel , Vladimir Zapolskiy , Avi Fishman , Tomer Maimon , Tali Perry , Patrick Venture , Nancy Yuen , Benjamin Fair , Pavel Machek , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-csky@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-sh@vger.kernel.org, xen-devel@lists.xenproject.org, linux-acpi@vger.kernel.org, linux-omap@vger.kernel.org, openbmc@lists.ozlabs.org, linux-tegra@vger.kernel.org, linux-pm@vger.kernel.org Add sanity check which ensures that there are no two restart handlers registered with the same priority. Normally it's a direct sign of a problem if two handlers use the same priority. Signed-off-by: Dmitry Osipenko --- kernel/reboot.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/kernel/reboot.c b/kernel/reboot.c index efb40d095d1e..d39e599c3c99 100644 --- a/kernel/reboot.c +++ b/kernel/reboot.c @@ -182,7 +182,20 @@ static ATOMIC_NOTIFIER_HEAD(restart_handler_list); */ int register_restart_handler(struct notifier_block *nb) { - return atomic_notifier_chain_register(&restart_handler_list, nb); + int ret; + + ret = atomic_notifier_chain_register(&restart_handler_list, nb); + if (ret) + return ret; + + /* + * Handler must have unique priority. Otherwise invocation order is + * determined by the registration order, which is presumed to be + * unreliable. + */ + WARN_ON(!atomic_notifier_has_unique_priority(&restart_handler_list, nb)); + + return 0; } EXPORT_SYMBOL(register_restart_handler); -- 2.33.1