queue-4.19/f2fs-fix-to-avoid-panic-in-f2fs_remove_inode_page.patch

   1 From ffcd55ace4fbcadc6781160828c066432ead4156 Mon Sep 17 00:00:00 2001
   2 From: Chao Yu <yuchao0@huawei.com>
   3 Date: Mon, 15 Apr 2019 15:28:34 +0800
   4 Subject: f2fs: fix to avoid panic in f2fs_remove_inode_page()
   5
   6 [ Upstream commit 8b6810f8acfe429fde7c7dad4714692cc5f75651 ]
   7
   8 As Jungyeon reported in bugzilla:
   9
  10 https://bugzilla.kernel.org/show_bug.cgi?id=203219
  11
  12 - Overview
  13 When mounting the attached crafted image and running program, I got this error.
  14 Additionally, it hangs on sync after running the program.
  15
  16 The image is intentionally fuzzed from a normal f2fs image for testing and I enabled option CONFIG_F2FS_CHECK_FS on.
  17
  18 - Reproduces
  19 cc poc_06.c
  20 mkdir test
  21 mount -t f2fs tmp.img test
  22 cp a.out test
  23 cd test
  24 sudo ./a.out
  25 sync
  26
  27 - Messages
  28  kernel BUG at fs/f2fs/node.c:1183!
  29  RIP: 0010:f2fs_remove_inode_page+0x294/0x2d0
  30  Call Trace:
  31   f2fs_evict_inode+0x2a3/0x3a0
  32   evict+0xba/0x180
  33   __dentry_kill+0xbe/0x160
  34   dentry_kill+0x46/0x180
  35   dput+0xbb/0x100
  36   do_renameat2+0x3c9/0x550
  37   __x64_sys_rename+0x17/0x20
  38   do_syscall_64+0x43/0xf0
  39   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  40
  41 The reason is f2fs_remove_inode_page() will trigger kernel panic due to
  42 inconsistent i_blocks value of inode.
  43
  44 To avoid panic, let's just print debug message and set SBI_NEED_FSCK to
  45 give a hint to fsck for latter repairing of potential image corruption.
  46
  47 Signed-off-by: Chao Yu <yuchao0@huawei.com>
  48 [Jaegeuk Kim: fix build warning and add unlikely]
  49 Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
  50 Signed-off-by: Sasha Levin <sashal@kernel.org>
  51 ---
  52  fs/f2fs/node.c | 10 ++++++++--
  53  1 file changed, 8 insertions(+), 2 deletions(-)
  54
  55 diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
  56 index 19a0d83aae65..807a77518a49 100644
  57 --- a/fs/f2fs/node.c
  58 +++ b/fs/f2fs/node.c
  59 @@ -1180,8 +1180,14 @@ int f2fs_remove_inode_page(struct inode *inode)
  60                 f2fs_put_dnode(&dn);
  61                 return -EIO;
  62         }
  63 -       f2fs_bug_on(F2FS_I_SB(inode),
  64 -                       inode->i_blocks != 0 && inode->i_blocks != 8);
  65 +
  66 +       if (unlikely(inode->i_blocks != 0 && inode->i_blocks != 8)) {
  67 +               f2fs_msg(F2FS_I_SB(inode)->sb, KERN_WARNING,
  68 +                       "Inconsistent i_blocks, ino:%lu, iblocks:%llu",
  69 +                       inode->i_ino,
  70 +                       (unsigned long long)inode->i_blocks);
  71 +               set_sbi_flag(F2FS_I_SB(inode), SBI_NEED_FSCK);
  72 +       }
  73
  74         /* will put inode & node pages */
  75         err = truncate_node(&dn);
  76 --
  77 2.20.1
  78