WARNING in ext4_direct_IO

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 7eb7037b Merge 4.4.156 into android-4.4
git tree: android-4.4
console output: https://syzkaller.appspot.com/x/log.txt?x=10729c1a400000
kernel config: https://syzkaller.appspot.com/x/.config?x=5b53d4a7d1498f1b
dashboard link: https://syzkaller.appspot.com/bug?extid=1eb502e5ec7bddc756df
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
userspace arch: i386
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=148456fa400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13b2839e400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+1eb502...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 0 PID: 2085 at fs/ext4/inode.c:3327 ext4_ext_direct_IO
fs/ext4/inode.c:3327 [inline]()
WARNING: CPU: 0 PID: 2085 at fs/ext4/inode.c:3327
ext4_direct_IO+0x22bc/0x2a60 fs/ext4/inode.c:3405()
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 2085 Comm: syz-executor028 Not tainted 4.4.156+ #35
0000000000000000 e3853cd986355ce0 ffff8800b6b77500 ffffffff81a557bd
ffffffff82835440 ffff8800b68297c0 ffffffff828beb80 0000000000000009
0000000000000cff ffff8800b6b775c0 ffffffff8138af34 0000000041b58ab3
Call Trace:
[<ffffffff81a557bd>] __dump_stack lib/dump_stack.c:15 [inline]
[<ffffffff81a557bd>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
[<ffffffff8138af34>] panic+0x19e/0x359 kernel/panic.c:112
[<ffffffff8138b124>] warn_slowpath_common.cold.6+0x20/0x20
kernel/panic.c:455
[<ffffffff810d18f9>] warn_slowpath_null+0x29/0x30 kernel/panic.c:492
[<ffffffff816109cc>] ext4_ext_direct_IO fs/ext4/inode.c:3327 [inline]
[<ffffffff816109cc>] ext4_direct_IO+0x22bc/0x2a60 fs/ext4/inode.c:3405
[<ffffffff813a3437>] generic_file_direct_write+0x267/0x4e0
mm/filemap.c:2493
[<ffffffff813a3904>] __generic_file_write_iter+0x254/0x550
mm/filemap.c:2673
[<ffffffff81602966>] ext4_file_write_iter+0x966/0xc80 fs/ext4/file.c:171
[<ffffffff81552be1>] aio_run_iocb+0x511/0x700 fs/aio.c:1475
[<ffffffff81557027>] io_submit_one fs/aio.c:1577 [inline]
[<ffffffff81557027>] do_io_submit+0x5b7/0xe50 fs/aio.c:1635
[<ffffffff8156ab13>] C_SYSC_io_submit fs/compat.c:651 [inline]
[<ffffffff8156ab13>] compat_SyS_io_submit+0xe3/0x130 fs/compat.c:636
[<ffffffff81005ffe>] do_syscall_32_irqs_on arch/x86/entry/common.c:393
[inline]
[<ffffffff81005ffe>] do_fast_syscall_32+0x31e/0x8b0
arch/x86/entry/common.c:460
[<ffffffff82692510>] sysenter_flags_fixed+0xd/0x1a
Kernel Offset: disabled
Rebooting in 86400 seconds..


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