Commit 2f183c68 authored by Jani Nikula's avatar Jani Nikula Committed by Andrew Morton
Browse files

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: default avatarJani Nikula <jani.nikula@intel.com>
Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent f36fc96c

include/linux/panic.h

+5 −3
Original line number Diff line number Diff line
@@ -80,6 +80,7 @@ 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 */

	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);

kernel/panic.c

+34 −11
Original line number Diff line number Diff line
@@ -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) {
@@ -520,9 +522,31 @@ 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;



		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;



	BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT);



	seq_buf_init(&s, buf, sizeof(buf));



	print_tainted_seq(&s);

	return _print_tainted(false);

}



	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)

lib/dump_stack.c

+3 −0
Original line number Diff line number Diff line
@@ -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);