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| author | Xiaochen Wang <wangxiaochen0@gmail.com> | 2011-05-01 11:41:41 +0800 |
|---|---|---|
| committer | Michal Marek <mmarek@suse.cz> | 2011-05-12 17:23:40 +0200 |
| commit | e0a04b11e4059cab033469617c2a3ce2d8cab416 (patch) | |
| tree | 4389bdde23d3d9308aa05c09eda1b44fab430330 /scripts/kallsyms.c | |
| parent | 153f01147065cb3628493dcb79417bc4474320c7 (diff) | |
scripts/kallsyms.c: fix potential segfault
Description:
This bug hardly appears during real kernel compiling,
because the vmlinux symbols table is huge.
But we can still catch it under strict condition , as follows.
$ echo "c101b97b T do_fork" | ./scripts/kallsyms --all-symbols
#include <asm/types.h>
......
......
.globl kallsyms_token_table
ALGN
kallsyms_token_table:
Segmentation fault (core dumped)
$
If symbols table is small, all entries in token_profit[0x10000] may
decrease to 0 after several calls of compress_symbols() in optimize_result().
In that case, find_best_token() always return 0 and
best_table[i] is set to "\0\0" and best_table_len[i] is set to 2.
As a result, expand_symbol(best_table[0]="\0\0", best_table_len[0]=2, buf)
in write_src() will run in infinite recursion until stack overflows,
causing segfault.
This patch checks the find_best_token() return value. If all entries in
token_profit[0x10000] become 0 according to return value, it breaks the loop
in optimize_result().
And expand_symbol() works well when best_table_len[i] is 0.
Signed-off-by: Xiaochen Wang <wangxiaochen0@gmail.com>
Acked-by: Paulo Marques <pmarques@grupopie.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Diffstat (limited to 'scripts/kallsyms.c')
| -rw-r--r-- | scripts/kallsyms.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 60dd3eb9366e..487ac6f37ca2 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -500,6 +500,8 @@ static void optimize_result(void) /* find the token with the breates profit value */ best = find_best_token(); + if (token_profit[best] == 0) + break; /* place it in the "best" table */ best_table_len[i] = 2; |