4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chao Yu <yuchao0@xxxxxxxxxx> [ 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@xxxxxxxxxx> Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/f2fs/extent_cache.c | 3 +++ 1 file changed, 3 insertions(+) --- a/fs/f2fs/extent_cache.c +++ b/fs/f2fs/extent_cache.c @@ -706,6 +706,9 @@ void f2fs_drop_extent_tree(struct 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);
