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kernel/panic: add verbose logging of kernel taints in backtraces

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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 <jani.nikula@intel.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Jani Nikula 2024-05-31 12:04:57 +03:00 committed by Andrew Morton
parent f36fc96c15
commit 2f183c6834
3 changed files with 42 additions and 14 deletions
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8
include/linux/panic.h
View File

@ -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);

45
kernel/panic.c
View File

@ -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)

3
lib/dump_stack.c
View File

@ -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);