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SubjectRe: [Patch] fs/binfmt_elf.c: fix a wrong free
On Sat, May 03, 2008 at 04:26:11PM +0300, Pekka J Enberg wrote:
>On Sat, 3 May 2008, WANG Cong wrote:
>> Fix a wrong free in fs/binfmt_elf.c::elf_core_dump().
>>
>> Signed-off-by: WANG Cong <wangcong@zeuux.org>
>> Cc: Alexander Viro <viro@zeniv.linux.org.uk>
>> Cc: Eric Youngdale <ericy@cais.com>
>>
>> ---
>> fs/binfmt_elf.c | 2 +-
>> 1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
>> index b25707f..43254e3 100644
>> --- a/fs/binfmt_elf.c
>> +++ b/fs/binfmt_elf.c
>> @@ -2032,10 +2032,10 @@ static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file, un
>>
>> end_coredump:
>> set_fs(fs);
>> + free_note_info(&info);
>>
>> cleanup:
>> kfree(elf);
>> - free_note_info(&info);
>> return has_dumped;
>> }
>
>Looks like fill_note_info() requires that you call free_note_info() if it
>fails; otherwise we'll leak memory. So perhaps something like the
>following totally untested patch?
>

Hi, Pekka!

Thanks for your comments. Yes, it seems that fill_note_info() is ugly.
:-) How about the below one?

Signed-off-by: WANG Cong <wangcong@zeuux.org>

---
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index f6d5a9d..357b503 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1900,7 +1900,7 @@ static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file, un
/* alloc memory for large data structures: too large to be on stack */
elf = kmalloc(sizeof(*elf), GFP_KERNEL);
if (!elf)
- goto cleanup;
+ goto ret;

segs = current->mm->map_count;
#ifdef ELF_CORE_EXTRA_PHDRS
@@ -2034,8 +2034,9 @@ end_coredump:
set_fs(fs);

cleanup:
- kfree(elf);
free_note_info(&info);
+ kfree(elf);
+ret:
return has_dumped;
}



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