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| author | Chao Yu <yuchao0@huawei.com> | 2021-05-07 18:10:38 +0800 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2021-05-14 11:22:08 -0700 |
| commit | cad83c968c2ebe97905f900326988ed37146c347 (patch) | |
| tree | 597783f54758209988cbd952cbce867d1ebac662 /fs/f2fs/recovery.c | |
| parent | b763f3bedc2da2edf81bba550430847f561eae0e (diff) | |
| download | linux-cad83c968c2ebe97905f900326988ed37146c347.tar.bz2 | |
f2fs: fix to avoid racing on fsync_entry_slab by multi filesystem instances
As syzbot reported, there is an use-after-free issue during f2fs recovery:
Use-after-free write at 0xffff88823bc16040 (in kfence-#10):
kmem_cache_destroy+0x1f/0x120 mm/slab_common.c:486
f2fs_recover_fsync_data+0x75b0/0x8380 fs/f2fs/recovery.c:869
f2fs_fill_super+0x9393/0xa420 fs/f2fs/super.c:3945
mount_bdev+0x26c/0x3a0 fs/super.c:1367
legacy_get_tree+0xea/0x180 fs/fs_context.c:592
vfs_get_tree+0x86/0x270 fs/super.c:1497
do_new_mount fs/namespace.c:2905 [inline]
path_mount+0x196f/0x2be0 fs/namespace.c:3235
do_mount fs/namespace.c:3248 [inline]
__do_sys_mount fs/namespace.c:3456 [inline]
__se_sys_mount+0x2f9/0x3b0 fs/namespace.c:3433
do_syscall_64+0x3f/0xb0 arch/x86/entry/common.c:47
entry_SYSCALL_64_after_hwframe+0x44/0xae
The root cause is multi f2fs filesystem instances can race on accessing
global fsync_entry_slab pointer, result in use-after-free issue of slab
cache, fixes to init/destroy this slab cache only once during module
init/destroy procedure to avoid this issue.
Reported-by: syzbot+9d90dad32dd9727ed084@syzkaller.appspotmail.com
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs/recovery.c')
| -rw-r--r-- | fs/f2fs/recovery.c | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c index 422146c6d866..4b2f7d1d5bf4 100644 --- a/fs/f2fs/recovery.c +++ b/fs/f2fs/recovery.c @@ -788,13 +788,6 @@ int f2fs_recover_fsync_data(struct f2fs_sb_info *sbi, bool check_only) quota_enabled = f2fs_enable_quota_files(sbi, s_flags & SB_RDONLY); #endif - fsync_entry_slab = f2fs_kmem_cache_create("f2fs_fsync_inode_entry", - sizeof(struct fsync_inode_entry)); - if (!fsync_entry_slab) { - err = -ENOMEM; - goto out; - } - INIT_LIST_HEAD(&inode_list); INIT_LIST_HEAD(&tmp_inode_list); INIT_LIST_HEAD(&dir_list); @@ -867,8 +860,6 @@ skip: } } - kmem_cache_destroy(fsync_entry_slab); -out: #ifdef CONFIG_QUOTA /* Turn quotas off */ if (quota_enabled) @@ -878,3 +869,17 @@ out: return ret ? ret : err; } + +int __init f2fs_create_recovery_cache(void) +{ + fsync_entry_slab = f2fs_kmem_cache_create("f2fs_fsync_inode_entry", + sizeof(struct fsync_inode_entry)); + if (!fsync_entry_slab) + return -ENOMEM; + return 0; +} + +void f2fs_destroy_recovery_cache(void) +{ + kmem_cache_destroy(fsync_entry_slab); +} |