From a54573d774735cc1f9d0e3bbf2c197c2d9523fe8 Mon Sep 17 00:00:00 2001
From: Wu Fengguang <fengguang.wu@intel.com>
Date: Tue, 6 Apr 2010 14:34:53 -0700
Subject: [PATCH] readahead: fix NULL filp dereference
commit 70655c06bd3f25111312d63985888112aed15ac5 upstream.
btrfs relocate_file_extent_cluster() calls us with NULL filp:
[ 4005.426805] BUG: unable to handle kernel NULL pointer dereference at 00000021
[ 4005.426818] IP: [<c109a130>] page_cache_sync_readahead+0x18/0x3e
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Yan Zheng <yanzheng@21cn.com>
Reported-by: Kirill A. Shutemov <kirill@shutemov.name>
Tested-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
mm/readahead.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/readahead.c b/mm/readahead.c
index 337b20e946f6..fe1a069fb595 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -502,7 +502,7 @@ void page_cache_sync_readahead(struct address_space *mapping,
return;
/* be dumb */
- if (filp->f_mode & FMODE_RANDOM) {
+ if (filp && (filp->f_mode & FMODE_RANDOM)) {
force_page_cache_readahead(mapping, filp, offset, req_size);
return;
}
--
2.34.1