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dyndbg: fix a BUG_ON in ddebug_describe_flags

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[ Upstream commit f678ce8cc3cb2ad29df75d8824c74f36398ba871 ]

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: <jbaron@akamai.com>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Link: https://lore.kernel.org/r/20200719231058.1586423-8-jim.cromie@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Jim Cromie 2020-07-19 17:10:47 -06:00 committed by Greg Kroah-Hartman
parent e1f67b2665
commit 2661310337
1 changed files with 11 additions and 12 deletions
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23
lib/dynamic_debug.c
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@ -85,22 +85,22 @@ 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 vpr_info(fmt, ...) \
@ -142,7 +142,7 @@ 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);
@ -199,8 +199,7 @@ static int ddebug_change(const struct ddebug_query *query,
vpr_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);
@ -779,7 +778,7 @@ 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;
vpr_info("called m=%p p=%p\n", m, p);
@ -792,7 +791,7 @@ 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");