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From: Jim Cromie <jim.cromie@gmail.com>
To: jbaron@akamai.com, linux-kernel@vger.kernel.org,
	akpm@linuxfoundation.org, gregkh@linuxfoundation.org
Cc: linux@rasmusvillemoes.dk, Jim Cromie <jim.cromie@gmail.com>
Subject: [PATCH v5 07/18] dyndbg: fix a BUG_ON in ddebug_describe_flags
Date: Sun, 19 Jul 2020 17:10:47 -0600	[thread overview]
Message-ID: <20200719231058.1586423-8-jim.cromie@gmail.com> (raw)
In-Reply-To: <20200719231058.1586423-1-jim.cromie@gmail.com>

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.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 9b2445507988..0cb5679f6c54 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -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");
 
-- 
2.26.2


  parent reply	other threads:[~2020-07-19 23:12 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-19 23:10 [PATCH v5 00/18] dynamic_debug fixes, cleanups, features, export Jim Cromie
2020-07-19 23:10 ` [PATCH v5 01/18] dyndbg-docs: eschew file /full/path query in docs Jim Cromie
2020-07-19 23:10 ` [PATCH v5 02/18] dyndbg-docs: initialization is done early, not arch Jim Cromie
2020-07-19 23:10 ` [PATCH v5 03/18] dyndbg: drop obsolete comment on ddebug_proc_open Jim Cromie
2020-07-19 23:10 ` [PATCH v5 04/18] dyndbg: refine debug verbosity; 1 is basic, 2 more chatty Jim Cromie
2020-07-19 23:10 ` [PATCH v5 05/18] dyndbg: rename __verbose section to __dyndbg Jim Cromie
2020-07-19 23:10 ` [PATCH v5 06/18] dyndbg: fix overcounting of ram used by dyndbg Jim Cromie
2020-07-19 23:10 ` Jim Cromie [this message]
2020-07-19 23:10 ` [PATCH v5 08/18] dyndbg: fix pr_err with empty string Jim Cromie
2020-07-19 23:10 ` [PATCH v5 09/18] dyndbg: prefer declarative init in caller, to memset in callee Jim Cromie
2020-07-19 23:10 ` [PATCH v5 10/18] dyndbg: make ddebug_tables list LIFO for add/remove_module Jim Cromie
2020-07-19 23:10 ` [PATCH v5 11/18] dyndbg: use gcc ?: to reduce word count Jim Cromie
2020-07-19 23:10 ` [PATCH v5 12/18] dyndbg: refactor parse_linerange out of ddebug_parse_query Jim Cromie
2020-07-19 23:10 ` [PATCH v5 13/18] dyndbg: accept 'file foo.c:func1' and 'file foo.c:10-100' Jim Cromie
2020-07-19 23:10 ` [PATCH v5 14/18] dyndbg: accept query terms like file=bar and module=foo Jim Cromie
2020-07-19 23:10 ` [PATCH v5 15/18] dyndbg: combine flags & mask into a struct, simplify with it Jim Cromie
2020-07-19 23:10 ` [PATCH v5 16/18] dyndbg: allow anchored match on format query term Jim Cromie
2020-07-19 23:10 ` [PATCH v5 17/18] dyndbg: shorten our logging prefix, drop __func__ Jim Cromie
2020-07-19 23:10 ` [PATCH v5 18/18] dyndbg: export ddebug_exec_queries Jim Cromie
2020-07-24 13:48 ` [PATCH v5 00/18] dynamic_debug fixes, cleanups, features, export Jason Baron
2020-07-24 14:59   ` Greg KH
2020-07-24 15:00     ` Greg KH

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