[patch 30/31] fix page leak during core dump

[Greg KH <gregkh@suse.de>]

[-- Attachment #1: fix-page-leak-during-core-dump.patch --]
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-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Brian Pomerantz <bapper@piratehaven.org>

When the dump cannot occur most likely because of a full file system and
the page to be written is the zero page, the call to page_cache_release()
is missed.

Signed-off-by: Brian Pomerantz <bapper@mvista.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: David Howells <dhowells@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 fs/binfmt_elf.c       |    5 ++++-
 fs/binfmt_elf_fdpic.c |    2 +-
 2 files changed, 5 insertions(+), 2 deletions(-)

--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1704,7 +1704,10 @@ static int elf_core_dump(long signr, str
 				DUMP_SEEK(PAGE_SIZE);
 			} else {
 				if (page == ZERO_PAGE(addr)) {
-					DUMP_SEEK(PAGE_SIZE);
+					if (!dump_seek(file, PAGE_SIZE)) {
+						page_cache_release(page);
+						goto end_coredump;
+					}
 				} else {
 					void *kaddr;
 					flush_cache_page(vma, addr,
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -1473,8 +1473,8 @@ static int elf_fdpic_dump_segments(struc
 				DUMP_SEEK(file->f_pos + PAGE_SIZE);
 			}
 			else if (page == ZERO_PAGE(addr)) {
-				DUMP_SEEK(file->f_pos + PAGE_SIZE);
 				page_cache_release(page);
+				DUMP_SEEK(file->f_pos + PAGE_SIZE);
 			}
 			else {
 				void *kaddr;

--