Commit d3ab3aa8 authored Jan 27, 2018 by Chao Yu Committed by Greg Kroah-Hartman May 30, 2018

f2fs: fix to check extent cache in f2fs_drop_extent_tree



[ Upstream commit bf617f7a92edc6bb2909db2bfa4576f50b280ee5 ]

If noextent_cache mount option is on, we will never initialize extent tree
in inode, but still we're going to access it in f2fs_drop_extent_tree,
result in kernel panic as below:

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000038
 IP: _raw_write_lock+0xc/0x30
 Call Trace:
  ? f2fs_drop_extent_tree+0x41/0x70 [f2fs]
  f2fs_fallocate+0x5a0/0xdd0 [f2fs]
  ? common_file_perm+0x47/0xc0
  ? apparmor_file_permission+0x1a/0x20
  vfs_fallocate+0x15b/0x290
  SyS_fallocate+0x44/0x70
  do_syscall_64+0x6e/0x160
  entry_SYSCALL64_slow_path+0x25/0x25

This patch fixes to check extent cache status before using in
f2fs_drop_extent_tree.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent a9d61754

fs/f2fs/extent_cache.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -647,6 +647,9 @@ void f2fs_drop_extent_tree(struct inode *inode)
		struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
		struct extent_tree *et = F2FS_I(inode)->extent_tree;

		if (!f2fs_may_extent_tree(inode))
		return;

		set_inode_flag(inode, FI_NO_EXTENT);

		write_lock(&et->lock);