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SubjectRe: [PATCH] fix memory leak while coredumping
IWAMOTO Toshihiro <iwamoto@valinux.co.jp> wrote:
>
> Hi,
>
> with some help of coworker, I found a bug in binfmt_elf.c.
> The bug exists in linux-2.6.1 and linux-2.6.2-rc2-mm2.
>
> This patch fixes a memory leak that happens when a core file hits the
> process's resource limit.
> I've tested the DUMP_WRITE case only a little, and the DUMP_SEEK case
> is only compile tested.
>
> --- old/fs/binfmt_elf.c Fri Jan 16 12:12:24 2004
> +++ new/fs/binfmt_elf.c Mon Feb 2 19:31:42 2004
> @@ -1441,12 +1441,22 @@
> DUMP_SEEK (file->f_pos + PAGE_SIZE);
> } else {
> if (page == ZERO_PAGE(addr)) {
> - DUMP_SEEK (file->f_pos + PAGE_SIZE);
> + if (!dump_seek(file,
> + file->f_pos + PAGE_SIZE)) {
> + page_cache_release(page);
> + goto end_coredump;
> + }

There's no point in doing page_cache_release() of the zero page.

> } else {
> void *kaddr;
> flush_cache_page(vma, addr);
> kaddr = kmap(page);
> - DUMP_WRITE(kaddr, PAGE_SIZE);
> + if ((size += PAGE_SIZE) > limit ||
> + !dump_write(file, kaddr,
> + PAGE_SIZE)) {
> + kunmap(page);
> + page_cache_release(page);
> + goto end_coredump;
> + }
> kunmap(page);
> }
> page_cache_release(page);

This chunk is good, thanks.

Those macros are foul.

-
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