4.9-stable review patch. If anyone has any objections, please let me know.
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From: Chao Yu yuchao0@huawei.com
[ 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 --- fs/f2fs/extent_cache.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/fs/f2fs/extent_cache.c +++ b/fs/f2fs/extent_cache.c @@ -647,6 +647,9 @@ 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);