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* [PATCH 06/16] dyndbg: fix a BUG_ON in ddebug_describe_flags
@ 2019-11-27 17:50 Jim Cromie
  2019-12-02 17:37 ` kbuild test robot
  0 siblings, 1 reply; 3+ messages in thread
From: Jim Cromie @ 2019-11-27 17:50 UTC (permalink / raw)
  To: jbaron, linux-kernel; +Cc: linux, greg, Jim Cromie

ddebug_describe_flags currently fills a caller provided string buffer,
after testing its size (also passed) in a BUG_ON.

Fix this with a struct containing a known-big-enough string buffer,
and passing it instead.

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 b5fb0aa0fbc3..0e4783e11755 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -62,6 +62,8 @@ struct ddebug_iter {
 	unsigned int idx;
 };
 
+struct flagsbuf { char buf[12]; };	/* big enough to hold all the flags */
+
 static DEFINE_MUTEX(ddebug_lock);
 static LIST_HEAD(ddebug_tables);
 static int verbose;
@@ -88,21 +90,19 @@ static struct { unsigned flag:8; char opt_char; } opt_array[] = {
 };
 
 /* 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, ...)				\
@@ -148,7 +148,7 @@ 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 flags;
 
 	/* search for matching ddebugs */
 	mutex_lock(&ddebug_lock);
@@ -205,8 +205,7 @@ 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, &flags));
 		}
 	}
 	mutex_unlock(&ddebug_lock);
@@ -820,7 +819,7 @@ 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;
 
 	v9pr_info("called m=%p p=%p\n", m, p);
 
@@ -833,7 +832,7 @@ 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");
 
-- 
2.23.0


^ permalink raw reply	[flat|nested] 3+ messages in thread
* [PATCH 00/16] dynamic_debug: cleanups, 2 features
@ 2020-06-05 16:26 Jim Cromie
  2020-06-05 16:26 ` [PATCH 06/16] dyndbg: fix a BUG_ON in ddebug_describe_flags Jim Cromie
  0 siblings, 1 reply; 3+ messages in thread
From: Jim Cromie @ 2020-06-05 16:26 UTC (permalink / raw)
  To: jbaron, linux-kernel, akpm, gregkh; +Cc: linux, Jim Cromie

Patchset starts with 7 "cleanups";
- it changes section name from vague "__verbose" to "__dyndbg"
- cleaner docs, drop obsolete comment & useless debug prints, refine
  verbosity, fix a BUG_ON, ram reporting miscounts.

It adds a few query parsing conveniences;
accept combined file:line & file:func forms

  file inode.c:100-200		# file & line-range
  file inode.c:start_*		# file & function

Then it expands flags:

Adds 'u' user flag, allowing user to compose an arbitrary set of
callsites by marking them with 'u', without altering current
print-modifying flags.

Adds 'PFMLTU' flags, which negate their lower-case counterparts.

Extends flags-spec with filter-flags, which select callsites for
modification based upon their current flags.  This lets user activate
the set of callsites marked with 'u' in a batch.

  echo 'u+p' > control

This was previously submitted before events overtook.
 v1: https://lkml.org/lkml/2019/10/29/989
 v2: https://lkml.org/lkml/2019/11/27/547

Jim Cromie (16):
cleanups:
  dyndbg-docs: eschew file /full/path query in docs
  dyndbg: drop obsolete comment on ddebug_proc_open
  dyndbg: refine debug verbosity
  dyndbg: rename __verbose section to __dyndbg
  dyndbg: fix overcounting of ram used by dyndbg
  dyndbg: fix a BUG_ON in ddebug_describe_flags
  dyndbg: make ddebug_tables list LIFO for add/remove_module
new features:
-parsing conveniences
  dyndbg: refactor parse_linerange out of ddebug_parse_query
  dyndbg: accept 'file foo.c:func1' and 'file foo.c:10-100'
-flags extensions
--internal rework
  dyndbg: refactor ddebug_read_flags out of ddebug_parse_flags
  dyndbg: combine flags & mask into a struct, use that
  dyndbg: add filter parameter to ddebug_parse_flags
  dyndbg: extend ddebug_parse_flags to accept optional filter-flags
  dyndbg: prefer declarative init in caller, to memset in callee
--expose the features
  dyndbg: add user-flag, negating-flags, and filtering on flags
  dyndbg: allow negating flag-chars in modflags

 .../admin-guide/dynamic-debug-howto.rst       |  75 +++--
 include/asm-generic/vmlinux.lds.h             |   6 +-
 include/linux/dynamic_debug.h                 |   5 +-
 kernel/module.c                               |   2 +-
 lib/dynamic_debug.c                           | 282 ++++++++++--------
 5 files changed, 225 insertions(+), 145 deletions(-)

-- 
2.26.2


^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-06-05 16:27 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-11-27 17:50 [PATCH 06/16] dyndbg: fix a BUG_ON in ddebug_describe_flags Jim Cromie
2019-12-02 17:37 ` kbuild test robot
2020-06-05 16:26 [PATCH 00/16] dynamic_debug: cleanups, 2 features Jim Cromie
2020-06-05 16:26 ` [PATCH 06/16] dyndbg: fix a BUG_ON in ddebug_describe_flags Jim Cromie

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