From 2f183c68345a26213e5e7f798399bee68d1c4a97 Mon Sep 17 00:00:00 2001 From: Jani Nikula Date: Fri, 31 May 2024 12:04:57 +0300 Subject: [PATCH] kernel/panic: add verbose logging of kernel taints in backtraces With nearly 20 taint flags and respective characters, it's getting a bit difficult to remember what each taint flag character means. Add verbose logging of the set taints in the format: Tainted: [P]=PROPRIETARY_MODULE, [W]=WARN in dump_stack_print_info() when there are taints. Note that the "negative flag" G is not included. Link: https://lkml.kernel.org/r/7321e306166cb2ca2807ab8639e665baa2462e9c.1717146197.git.jani.nikula@intel.com Signed-off-by: Jani Nikula Reviewed-by: Greg Kroah-Hartman Signed-off-by: Andrew Morton --- include/linux/panic.h | 8 +++++--- kernel/panic.c | 45 ++++++++++++++++++++++++++++++++----------- lib/dump_stack.c | 3 +++ 3 files changed, 42 insertions(+), 14 deletions(-) diff --git a/include/linux/panic.h b/include/linux/panic.h index 6717b15e798c..3130e0b5116b 100644 --- a/include/linux/panic.h +++ b/include/linux/panic.h @@ -77,9 +77,10 @@ static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout) #define TAINT_FLAGS_MAX ((1UL << TAINT_FLAGS_COUNT) - 1) struct taint_flag { - char c_true; /* character printed when tainted */ - char c_false; /* character printed when not tainted */ - bool module; /* also show as a per-module taint flag */ + char c_true; /* character printed when tainted */ + char c_false; /* character printed when not tainted */ + bool module; /* also show as a per-module taint flag */ + const char *desc; /* verbose description of the set taint flag */ }; extern const struct taint_flag taint_flags[TAINT_FLAGS_COUNT]; @@ -90,6 +91,7 @@ enum lockdep_ok { }; extern const char *print_tainted(void); +extern const char *print_tainted_verbose(void); extern void add_taint(unsigned flag, enum lockdep_ok); extern int test_taint(unsigned flag); extern unsigned long get_taint(void); diff --git a/kernel/panic.c b/kernel/panic.c index 21975497bfa4..f861bedc1925 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -475,6 +475,7 @@ EXPORT_SYMBOL(panic); [ TAINT_##taint ] = { \ .c_true = _c_true, .c_false = _c_false, \ .module = _module, \ + .desc = #taint, \ } /* @@ -505,8 +506,9 @@ const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = { #undef TAINT_FLAG -static void print_tainted_seq(struct seq_buf *s) +static void print_tainted_seq(struct seq_buf *s, bool verbose) { + const char *sep = ""; int i; if (!tainted_mask) { @@ -520,10 +522,32 @@ static void print_tainted_seq(struct seq_buf *s) bool is_set = test_bit(i, &tainted_mask); char c = is_set ? t->c_true : t->c_false; - seq_buf_putc(s, c); + if (verbose) { + if (is_set) { + seq_buf_printf(s, "%s[%c]=%s", sep, c, t->desc); + sep = ", "; + } + } else { + seq_buf_putc(s, c); + } } } +static const char *_print_tainted(bool verbose) +{ + /* FIXME: what should the size be? */ + static char buf[sizeof(taint_flags)]; + struct seq_buf s; + + BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT); + + seq_buf_init(&s, buf, sizeof(buf)); + + print_tainted_seq(&s, verbose); + + return seq_buf_str(&s); +} + /** * print_tainted - return a string to represent the kernel taint state. * @@ -534,16 +558,15 @@ static void print_tainted_seq(struct seq_buf *s) */ const char *print_tainted(void) { - static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")]; - struct seq_buf s; + return _print_tainted(false); +} - BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT); - - seq_buf_init(&s, buf, sizeof(buf)); - - print_tainted_seq(&s); - - return seq_buf_str(&s); +/** + * print_tainted_verbose - A more verbose version of print_tainted() + */ +const char *print_tainted_verbose(void) +{ + return _print_tainted(true); } int test_taint(unsigned flag) diff --git a/lib/dump_stack.c b/lib/dump_stack.c index 222c6d6c8281..8b6b70eaf949 100644 --- a/lib/dump_stack.c +++ b/lib/dump_stack.c @@ -62,6 +62,9 @@ void dump_stack_print_info(const char *log_lvl) (int)strcspn(init_utsname()->version, " "), init_utsname()->version, BUILD_ID_VAL); + if (get_taint()) + printk("%s%s\n", log_lvl, print_tainted_verbose()); + if (dump_stack_arch_desc_str[0] != '\0') printk("%sHardware name: %s\n", log_lvl, dump_stack_arch_desc_str);