[PATCH 01/15] taint: add module firmware crash taint support
From: Luis Chamberlain <mcgrof@kernel.org>
Date: 2020-05-09 04:36:08
Also in:
lkml
Subsystem:
module support, the rest, tracing · Maintainers:
Luis Chamberlain, Petr Pavlu, Daniel Gomez, Sami Tolvanen, Linus Torvalds, Steven Rostedt, Masami Hiramatsu
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 <mcgrof@kernel.org> --- include/linux/kernel.h | 3 ++- include/linux/module.h | 13 +++++++++++++ include/trace/events/module.h | 3 ++- kernel/module.c | 5 +++-- kernel/panic.c | 1 + 5 files changed, 21 insertions(+), 4 deletions(-)
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 }, }; /**
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2.25.1