* [PATCH] kallsyms: Fix segfault in prefix_underscores_count().
@ 2009-08-07 9:22 Paul Mundt
0 siblings, 0 replies; only message in thread
From: Paul Mundt @ 2009-08-07 9:22 UTC (permalink / raw)
To: Sam Ravnborg; +Cc: Lai Jiangshan, linux-next
As a good indicator that Impact lines are completely useless, commit
b478b782e110fdb4135caa3062b6d687e989d994 "kallsyms, tracing: output more
proper symbol name" introduces a "bugfix" that introduced segfaults on
several of my defconfigs:
http://kisskb.ellerman.id.au/kisskb/buildresult/1017849/
http://kisskb.ellerman.id.au/kisskb/buildresult/1017351/
http://kisskb.ellerman.id.au/kisskb/buildresult/1017354/
The cause is the introduction of prefix_underscores_count() which
attempts to count underscores.. even in symbols that do not have them.
As a result, it just uselessly runs past the end of the buffer until it
crashes.
This adds a strlen iterator that bails out if nothing is found in the
string, which fixes up the observed segfaults.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
---
I've uploaded the symbol list to:
http://userweb.kernel.org/~lethal/symbol-list.gz
that one can pipe in to scripts/kallsyms to reproduce the fault in -next,
incase someone wants to come up with a better fix :-)
scripts/kallsyms.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 64343cc..f1d44b2 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -584,9 +538,14 @@ static int may_be_linker_script_provide_symbol(const struct sym_entry *se)
static int prefix_underscores_count(const char *str)
{
const char *tail = str;
+ size_t len = strlen(str);
+
+ while (*tail != '_') {
+ if (!len--)
+ return 0;
- while (*tail != '_')
tail++;
+ }
return tail - str;
}
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2009-08-07 9:22 [PATCH] kallsyms: Fix segfault in prefix_underscores_count() Paul Mundt
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