• Jan Kara's avatar
    ext4: avoid crash when inline data creation follows DIO write · 4bb26f28
    Jan Kara authored
    When inode is created and written to using direct IO, there is nothing
    to clear the EXT4_STATE_MAY_INLINE_DATA flag. Thus when inode gets
    truncated later to say 1 byte and written using normal write, we will
    try to store the data as inline data. This confuses the code later
    because the inode now has both normal block and inline data allocated
    and the confusion manifests for example as:
    
    kernel BUG at fs/ext4/inode.c:2721!
    invalid opcode: 0000 [#1] PREEMPT SMP KASAN
    CPU: 0 PID: 359 Comm: repro Not tainted 5.19.0-rc8-00001-g31ba1e3b8305-dirty #15
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.fc36 04/01/2014
    RIP: 0010:ext4_writepages+0x363d/0x3660
    RSP: 0018:ffffc90000ccf260 EFLAGS: 00010293
    RAX: ffffffff81e1abcd RBX: 0000008000000000 RCX: ffff88810842a180
    RDX: 0000000000000000 RSI: 0000008000000000 RDI: 0000000000000000
    RBP: ffffc90000ccf650 R08: ffffffff81e17d58 R09: ffffed10222c680b
    R10: dfffe910222c680c R11: 1ffff110222c680a R12: ffff888111634128
    R13: ffffc90000ccf880 R14: 0000008410000000 R15: 0000000000000001
    FS:  00007f72635d2640(0000) GS:ffff88811b000000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 0000565243379180 CR3: 000000010aa74000 CR4: 0000000000150eb0
    Call Trace:
     <TASK>
     do_writepages+0x397/0x640
     filemap_fdatawrite_wbc+0x151/0x1b0
     file_write_and_wait_range+0x1c9/0x2b0
     ext4_sync_file+0x19e/0xa00
     vfs_fsync_range+0x17b/0x190
     ext4_buffered_write_iter+0x488/0x530
     ext4_file_write_iter+0x449/0x1b90
     vfs_write+0xbcd/0xf40
     ksys_write+0x198/0x2c0
     __x64_sys_write+0x7b/0x90
     do_syscall_64+0x3d/0x90
     entry_SYSCALL_64_after_hwframe+0x63/0xcd
     </TASK>
    
    Fix the problem by clearing EXT4_STATE_MAY_INLINE_DATA when we are doing
    direct IO write to a file.
    
    Cc: stable@kernel.org
    Reported-by: default avatarTadeusz Struk <tadeusz.struk@linaro.org>
    Reported-by: syzbot+bd13648a53ed6933ca49@syzkaller.appspotmail.com
    Link: https://syzkaller.appspot.com/bug?id=a1e89d09bbbcbd5c4cb45db230ee28c822953984Signed-off-by: default avatarJan Kara <jack@suse.cz>
    Reviewed-by: default avatarLukas Czerner <lczerner@redhat.com>
    Tested-by: Tadeusz Struk<tadeusz.struk@linaro.org>
    Link: https://lore.kernel.org/r/20220727155753.13969-1-jack@suse.czSigned-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
    4bb26f28
file.c 24.2 KB