lkml.org 
[lkml]   [2012]   [Mar]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] vsprintf: make %pV handling compatible with kasprintf()
kasprintf() (and potentially other functions that I didn't run across
so far) want to evaluate argument lists twice. Caring to do so for the
primary list is obviously their job, but they can't reasonably be
expected to check the format string for instances of %pV, which however
need special handling too: On architectures like x86-64 (as opposed to
e.g. ix86), using the same argument list twice doesn't produce the
expected results, as an internally managed cursor gets updated during
the first run.

Fix the problem by always acting on a copy of the original list when
handling %pV.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

---
lib/vsprintf.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

--- 3.3-rc6/lib/vsprintf.c
+++ 3.3-rc6-kasprintf-pV/lib/vsprintf.c
@@ -891,9 +891,15 @@ char *pointer(const char *fmt, char *buf
case 'U':
return uuid_string(buf, end, ptr, spec, fmt);
case 'V':
- return buf + vsnprintf(buf, end > buf ? end - buf : 0,
- ((struct va_format *)ptr)->fmt,
- *(((struct va_format *)ptr)->va));
+ {
+ va_list va;
+
+ va_copy(va, *((struct va_format *)ptr)->va);
+ buf += vsnprintf(buf, end > buf ? end - buf : 0,
+ ((struct va_format *)ptr)->fmt, va);
+ va_end(va);
+ return buf;
+ }
case 'K':
/*
* %pK cannot be used in IRQ context because its test




\
 
 \ /
  Last update: 2012-03-05 17:51    [W:0.030 / U:0.448 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site