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authorWu Fengguang <fengguang.wu@intel.com>2010-04-06 14:34:53 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-04-07 08:38:03 -0700
commit70655c06bd3f25111312d63985888112aed15ac5 (patch)
treee6db465a10b6ece8f50fbcfce97404f03044e248
parent12765517d9dbb477a2432375938f1eb5bdbcb532 (diff)
downloadlinux-70655c06bd3f25111312d63985888112aed15ac5.tar.bz2
readahead: fix NULL filp dereference
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> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/readahead.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/readahead.c b/mm/readahead.c
index 999b54bb462f..dfa9a1a03a11 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -503,7 +503,7 @@ 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;
}