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[157.230.128.187]) by smtp.gmail.com with ESMTPSA id 14sm2700222pfy.38.2020.05.15.14.28.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 15 May 2020 14:28:50 -0700 (PDT) Received: by 42.do-not-panic.com (Postfix, from userid 1000) id 863A040E7B; Fri, 15 May 2020 21:28:49 +0000 (UTC) From: Luis Chamberlain To: jeyu@kernel.org Cc: akpm@linux-foundation.org, arnd@arndb.de, rostedt@goodmis.org, mingo@redhat.com, aquini@redhat.com, cai@lca.pw, dyoung@redhat.com, bhe@redhat.com, peterz@infradead.org, tglx@linutronix.de, gpiccoli@canonical.com, pmladek@suse.com, tiwai@suse.de, schlad@suse.de, andriy.shevchenko@linux.intel.com, keescook@chromium.org, daniel.vetter@ffwll.ch, will@kernel.org, mchehab+samsung@kernel.org, kvalo@codeaurora.org, davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Luis Chamberlain Subject: [PATCH v2 01/15] taint: add module firmware crash taint support Date: Fri, 15 May 2020 21:28:32 +0000 Message-Id: <20200515212846.1347-2-mcgrof@kernel.org> X-Mailer: git-send-email 2.23.0.rc1 In-Reply-To: <20200515212846.1347-1-mcgrof@kernel.org> References: <20200515212846.1347-1-mcgrof@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Device driver firmware can crash, and sometimes, this can leave your system in a state which makes the device or subsystem completely useless. Detecting this by inspecting /proc/sys/kernel/tainted instead of scraping some magical words from the kernel log, which is driver specific, is much easier. So instead provide a helper which lets drivers annotate this. Once this happens, scrapers can easily look for modules taint flags for a firmware crash. This will taint both the kernel and respective calling module. The new helper module_firmware_crashed() uses LOCKDEP_STILL_OK as this fact should in no way shape or form affect lockdep. This taint is device driver specific. Signed-off-by: Luis Chamberlain --- Documentation/admin-guide/tainted-kernels.rst | 6 ++++++ include/linux/kernel.h | 3 ++- include/linux/module.h | 13 +++++++++++++ include/trace/events/module.h | 3 ++- kernel/module.c | 5 +++-- kernel/panic.c | 1 + tools/debugging/kernel-chktaint | 7 +++++++ 7 files changed, 34 insertions(+), 4 deletions(-) diff --git a/Documentation/admin-guide/tainted-kernels.rst b/Documentation/admin-guide/tainted-kernels.rst index 71e9184a9079..92530f1d60ae 100644 --- a/Documentation/admin-guide/tainted-kernels.rst +++ b/Documentation/admin-guide/tainted-kernels.rst @@ -100,6 +100,7 @@ Bit Log Number Reason that got the kernel tainted 15 _/K 32768 kernel has been live patched 16 _/X 65536 auxiliary taint, defined for and used by distros 17 _/T 131072 kernel was built with the struct randomization plugin + 18 _/Q 262144 driver firmware crash annotation === === ====== ======================================================== Note: The character ``_`` is representing a blank in this table to make reading @@ -162,3 +163,8 @@ More detailed explanation for tainting produce extremely unusual kernel structure layouts (even performance pathological ones), which is important to know when debugging. Set at build time. + + 18) ``Q`` used by device drivers to annotate that the device driver's firmware + has crashed and the device's operation has been severely affected. The + device may be left in a crippled state, requiring full driver removal / + addition, system reboot, or it is unclear how long recovery will take. diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 04a5885cec1b..19e1541c82c7 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -601,7 +601,8 @@ extern enum system_states { #define TAINT_LIVEPATCH 15 #define TAINT_AUX 16 #define TAINT_RANDSTRUCT 17 -#define TAINT_FLAGS_COUNT 18 +#define TAINT_FIRMWARE_CRASH 18 +#define TAINT_FLAGS_COUNT 19 struct taint_flag { char c_true; /* character printed when tainted */ diff --git a/include/linux/module.h b/include/linux/module.h index 2c2e988bcf10..221200078180 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -697,6 +697,14 @@ static inline bool is_livepatch_module(struct module *mod) bool is_module_sig_enforced(void); void set_module_sig_enforced(void); +void add_taint_module(struct module *mod, unsigned flag, + enum lockdep_ok lockdep_ok); + +static inline void module_firmware_crashed(void) +{ + add_taint_module(THIS_MODULE, TAINT_FIRMWARE_CRASH, LOCKDEP_STILL_OK); +} + #else /* !CONFIG_MODULES... */ static inline struct module *__module_address(unsigned long addr) @@ -844,6 +852,11 @@ void *dereference_module_function_descriptor(struct module *mod, void *ptr) return ptr; } +static inline void module_firmware_crashed(void) +{ + add_taint(TAINT_FIRMWARE_CRASH, LOCKDEP_STILL_OK); +} + #endif /* CONFIG_MODULES */ #ifdef CONFIG_SYSFS diff --git a/include/trace/events/module.h b/include/trace/events/module.h index 097485c73c01..b749ea25affd 100644 --- a/include/trace/events/module.h +++ b/include/trace/events/module.h @@ -26,7 +26,8 @@ struct module; { (1UL << TAINT_OOT_MODULE), "O" }, \ { (1UL << TAINT_FORCED_MODULE), "F" }, \ { (1UL << TAINT_CRAP), "C" }, \ - { (1UL << TAINT_UNSIGNED_MODULE), "E" }) + { (1UL << TAINT_UNSIGNED_MODULE), "E" }, \ + { (1UL << TAINT_FIRMWARE_CRASH), "Q" }) TRACE_EVENT(module_load, diff --git a/kernel/module.c b/kernel/module.c index 80faaf2116dd..f98e8c25c6b4 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -325,12 +325,13 @@ static inline int strong_try_module_get(struct module *mod) return -ENOENT; } -static inline void add_taint_module(struct module *mod, unsigned flag, - enum lockdep_ok lockdep_ok) +void add_taint_module(struct module *mod, unsigned flag, + enum lockdep_ok lockdep_ok) { add_taint(flag, lockdep_ok); set_bit(flag, &mod->taints); } +EXPORT_SYMBOL_GPL(add_taint_module); /* * A thread that wants to hold a reference to a module only while it diff --git a/kernel/panic.c b/kernel/panic.c index ec6d7d788ce7..504fb926947e 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -384,6 +384,7 @@ const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = { [ TAINT_LIVEPATCH ] = { 'K', ' ', true }, [ TAINT_AUX ] = { 'X', ' ', true }, [ TAINT_RANDSTRUCT ] = { 'T', ' ', true }, + [ TAINT_FIRMWARE_CRASH ] = { 'Q', ' ', true }, }; /** diff --git a/tools/debugging/kernel-chktaint b/tools/debugging/kernel-chktaint index 2240cb56e6e5..c397c6aabea7 100755 --- a/tools/debugging/kernel-chktaint +++ b/tools/debugging/kernel-chktaint @@ -194,6 +194,13 @@ else addout "T" echo " * kernel was built with the struct randomization plugin (#17)" fi +T=`expr $T / 2` +if [ `expr $T % 2` -eq 0 ]; then + addout " " +else + addout "Q" + echo " * a device driver's firmware has crashed (#18)" +fi echo "For a more detailed explanation of the various taint flags see" echo " Documentation/admin-guide/tainted-kernels.rst in the the Linux kernel sources" -- 2.26.2