On 2021/7/22 12:41, Jack Qiu wrote:
The root cause is shrink_dcache_sb after sbi has been freed.
So call shrink_dcache_sb before free sbi and other resources.

==================================================================
BUG: KASAN: use-after-free in f2fs_evict_inode+0x31c/0xde5
Read of size 4 at addr ffff8881d97f0d50 by task syz-executor.3/8729

PU: 1 PID: 8729 Comm: syz-executor.3 Not tainted
4.19.195-00002-g67dceea04431-dirty #31

Does this bug below to 4.19.195?

Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31
04/01/2014
Call Trace:
  dump_stack+0xe5/0x14b
  ? f2fs_evict_inode+0x31c/0xde5
  print_address_description+0x6c/0x237
  ? f2fs_evict_inode+0x31c/0xde5
  kasan_report.cold+0x88/0x2a3
  f2fs_evict_inode+0x31c/0xde5
  ? full_proxy_open.cold+0x12/0x12
  evict+0x2cd/0x5f0
  iput+0x3d9/0x6f0
  dentry_unlink_inode+0x273/0x330
  __dentry_kill+0x340/0x5e0
  dentry_kill+0xb7/0x740
  shrink_dentry_list+0x256/0x660
  shrink_dcache_sb+0x11f/0x1d0
  ? shrink_dentry_list+0x660/0x660
  ? __kasan_slab_free+0x144/0x180
  f2fs_fill_super+0x2a34/0x4a80
  ? f2fs_sanity_check_ckpt.cold+0x2b6/0x2b6
  ? wait_for_completion+0x3c0/0x3c0
  ? set_blocksize+0x230/0x2b0
  mount_bdev+0x2c1/0x370
  ? f2fs_sanity_check_ckpt.cold+0x2b6/0x2b6
  mount_fs+0x4c/0x1c0
  vfs_kern_mount.part.0+0x60/0x3d0
  do_mount+0x367/0x2570
  ? kasan_unpoison_shadow+0x33/0x40
  ? copy_mount_string+0x40/0x40
  ? kmem_cache_alloc_trace+0x13f/0x2b0
  ? _copy_from_user+0x94/0x100
  ? copy_mount_options+0x1f1/0x2e0
  ksys_mount+0xa0/0x100
  __x64_sys_mount+0xbf/0x160
  do_syscall_64+0xc2/0x190
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x47938e
Code: 48 c7 c1 b4 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84
00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01
f0 ff ff 73 01 c3 48 c7 c1 b4 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fed673b6a48 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000020000200 RCX: 000000000047938e
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fed673b6aa0
RBP: 00007fed673b6ae0 R08: 00007fed673b6ae0 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020000000
R13: 0000000020000100 R14: 00007fed673b6aa0 R15: 0000000020000b00

Allocated by task 8729:
  kasan_kmalloc+0xc2/0xe0
  kmem_cache_alloc_trace+0x13f/0x2b0
  f2fs_fill_super+0x124/0x4a80
  mount_bdev+0x2c1/0x370
  mount_fs+0x4c/0x1c0
  vfs_kern_mount.part.0+0x60/0x3d0
  do_mount+0x367/0x2570
  ksys_mount+0xa0/0x100
  __x64_sys_mount+0xbf/0x160
  do_syscall_64+0xc2/0x190
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 8729:
  __kasan_slab_free+0x12f/0x180
  kfree+0xfa/0x2a0
  f2fs_fill_super+0x2a00/0x4a80
  mount_bdev+0x2c1/0x370
  mount_fs+0x4c/0x1c0
  vfs_kern_mount.part.0+0x60/0x3d0
  do_mount+0x367/0x2570
  ksys_mount+0xa0/0x100
  __x64_sys_mount+0xbf/0x160
  do_syscall_64+0xc2/0x190
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

Signed-off-by: Jack Qiu <[email protected]>
---
  fs/f2fs/super.c | 3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 8fecd3050ccd..b041625e06ce 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -4229,6 +4229,8 @@ static int f2fs_fill_super(struct super_block *sb, void 
*data, int silent)
  free_compress_inode:
        f2fs_destroy_compress_inode(sbi);
  free_root_inode:
+       if (retry_cnt > 0 && skip_recovery)
+               shrink_dcache_sb(sb);

Compare to 4.19, last f2fs adds evict_inodes() before f2fs_unregister_sysfs(),
could you please check whether this can fix the issue?

Thanks,

        dput(sb->s_root);
        sb->s_root = NULL;
  free_node_inode:
@@ -4285,7 +4287,6 @@ static int f2fs_fill_super(struct super_block *sb, void 
*data, int silent)
        /* give only one another chance */
        if (retry_cnt > 0 && skip_recovery) {
                retry_cnt--;
-               shrink_dcache_sb(sb);
                goto try_onemore;
        }
        return err;
--
2.17.1



_______________________________________________
Linux-f2fs-devel mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

Reply via email to