Commit f678ce8c authored by Jim Cromie's avatar Jim Cromie Committed by Greg Kroah-Hartman
Browse files

dyndbg: fix a BUG_ON in ddebug_describe_flags 



ddebug_describe_flags() currently fills a caller provided string buffer,
after testing its size (also passed) in a BUG_ON.  Fix this by
replacing them with a known-big-enough string buffer wrapped in a
struct, and passing that instead.

Also simplify ddebug_describe_flags() flags parameter from a struct to
a member in that struct, and hoist the member deref up to the caller.
This makes the function reusable (soon) where flags are unpacked.

Acked-by: default avatar <jbaron@akamai.com>
Signed-off-by: default avatarJim Cromie <jim.cromie@gmail.com>
Link: https://lore.kernel.org/r/20200719231058.1586423-8-jim.cromie@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 81d0c2c6

lib/dynamic_debug.c

+11 −12
Original line number Diff line number Diff line
@@ -87,22 +87,22 @@ static struct { unsigned flag:8; char opt_char; } opt_array[] = { 
	{ _DPRINTK_FLAGS_NONE, '_' },

};



struct flagsbuf { char buf[ARRAY_SIZE(opt_array)+1]; };



/* format a string into buf[] which describes the _ddebug's flags */

static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,

				    size_t maxlen)

static char *ddebug_describe_flags(unsigned int flags, struct flagsbuf *fb)

{

	char *p = buf;

	char *p = fb->buf;

	int i;



	BUG_ON(maxlen < 6);

	for (i = 0; i < ARRAY_SIZE(opt_array); ++i)

		if (dp->flags & opt_array[i].flag)

		if (flags & opt_array[i].flag)

			*p++ = opt_array[i].opt_char;

	if (p == buf)

	if (p == fb->buf)

		*p++ = '_';

	*p = '\0';



	return buf;

	return fb->buf;

}



#define vnpr_info(lvl, fmt, ...)				\
@@ -147,7 +147,7 @@ static int ddebug_change(const struct ddebug_query *query, 
	struct ddebug_table *dt;

	unsigned int newflags;

	unsigned int nfound = 0;

	char flagbuf[10];

	struct flagsbuf fbuf;



	/* search for matching ddebugs */

	mutex_lock(&ddebug_lock);
@@ -204,8 +204,7 @@ static int ddebug_change(const struct ddebug_query *query, 
			v2pr_info("changed %s:%d [%s]%s =%s\n",

				 trim_prefix(dp->filename), dp->lineno,

				 dt->mod_name, dp->function,

				 ddebug_describe_flags(dp, flagbuf,

						       sizeof(flagbuf)));

				 ddebug_describe_flags(dp->flags, &fbuf));

		}

	}

	mutex_unlock(&ddebug_lock);
@@ -814,7 +813,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p) 
{

	struct ddebug_iter *iter = m->private;

	struct _ddebug *dp = p;

	char flagsbuf[10];

	struct flagsbuf flags;



	if (p == SEQ_START_TOKEN) {

		seq_puts(m,
@@ -825,7 +824,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p) 
	seq_printf(m, "%s:%u [%s]%s =%s \"",

		   trim_prefix(dp->filename), dp->lineno,

		   iter->table->mod_name, dp->function,

		   ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));

		   ddebug_describe_flags(dp->flags, &flags));

	seq_escape(m, dp->format, "\t\r\n\"");

	seq_puts(m, "\"\n");

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