Re: WARNING in ext4_invalidatepage

From: Dmitry Vyukov <dvyukov@google.com>
To: syzbot <syzbot+85da7ac734f7ba432ee4@syzkaller.appspotmail.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>,
	linux-ext4@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
	syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
	"Theodore Ts'o" <tytso@mit.edu>
Subject: Re: WARNING in ext4_invalidatepage
Date: Mon, 8 Oct 2018 18:29:54 +0200	[thread overview]
Message-ID: <CACT4Y+bdR3ch9q_FCND4YmqjunYBVbEk3n167DT0r0GqzVKL-g@mail.gmail.com> (raw)
In-Reply-To: <0000000000002753c60577b9f707@google.com>

On Mon, Oct 8, 2018 at 6:18 PM, syzbot
<syzbot+85da7ac734f7ba432ee4@syzkaller.appspotmail.com> wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit:    c1d84a1b42ef Merge git://git.kernel.org/pub/scm/linux/kern..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=161588d6400000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=c0af03fe452b65fb
> dashboard link: https://syzkaller.appspot.com/bug?extid=85da7ac734f7ba432ee4
> compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
>
> Unfortunately, I don't have any reproducer for this crash yet.
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+85da7ac734f7ba432ee4@syzkaller.appspotmail.com

The program that triggered it did the following:

05:23:28 executing program 5:
r0 = creat(&(0x7f00000001c0)='./file0\x00', 0x0)
socketpair$unix(0x1, 0x1, 0x0, &(0x7f0000000380)={0xffffffffffffffff,
<r1=>0xffffffffffffffff})
write$RDMA_USER_CM_CMD_CREATE_ID(r0, &(0x7f0000000240)={0x0, 0x18,
0xfa00, {0x0, &(0x7f0000000200)}}, 0x20)
ioctl$PERF_EVENT_IOC_ENABLE(r1, 0x8912, 0x400200)
ioctl$EXT4_IOC_SETFLAGS(r0, 0x4008660f, &(0x7f0000000000)=0x4000)

Seems like some bad interaction of unix sockets and ext4.

> WARNING: CPU: 1 PID: 17203 at fs/ext4/inode.c:3353
> ext4_invalidatepage+0x1c7/0x5b0 fs/ext4/inode.c:3353
> Kernel panic - not syncing: panic_on_warn set ...
>
> CPU: 1 PID: 17203 Comm: syz-executor5 Not tainted 4.19.0-rc6+ #48
> kobject: 'loop3' (000000002393f9b0): kobject_uevent_env
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Call Trace:
>  __dump_stack lib/dump_stack.c:77 [inline]
>  dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113
> kobject: 'loop3' (000000002393f9b0): fill_kobj_path: path =
> '/devices/virtual/block/loop3'
>  panic+0x238/0x4e7 kernel/panic.c:184
>  __warn.cold.8+0x163/0x1ba kernel/panic.c:536
>  report_bug+0x254/0x2d0 lib/bug.c:186
>  fixup_bug arch/x86/kernel/traps.c:178 [inline]
>  do_error_trap+0x1fc/0x4d0 arch/x86/kernel/traps.c:296
>  do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
>  invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:993
> RIP: 0010:ext4_invalidatepage+0x1c7/0x5b0 fs/ext4/inode.c:3353
> Code: 80 3c 02 00 0f 85 a7 03 00 00 4d 8b 6d 00 31 ff 49 c1 ed 11 41 83 e5
> 01 4c 89 ee e8 43 ea 67 ff 4d 85 ed 74 07 e8 09 e9 67 ff <0f> 0b e8 02 e9 67
> ff 8b b5 34 ff ff ff 44 89 fa 4c 89 e7 e8 91 3a
> RSP: 0018:ffff88018590ec78 EFLAGS: 00010212
> RAX: 0000000000040000 RBX: 1ffff10030b21d91 RCX: ffffc9000dae4000
> RDX: 0000000000000ece RSI: ffffffff8216ec87 RDI: 0000000000000007
> RBP: ffff88018590ed50 R08: ffff880183018300 R09: fffff94000ceffc6
> R10: fffff94000ceffc6 R11: ffffea000677fe33 R12: ffffea000677fe00
> R13: 0000000000000001 R14: ffffea000677fe08 R15: 0000000000001000
>  do_invalidatepage mm/truncate.c:165 [inline]
>  truncate_cleanup_page+0x5ac/0xa90 mm/truncate.c:187
>  truncate_inode_page+0x107/0x1a0 mm/truncate.c:229
>  truncate_inode_pages_range+0x1382/0x2d50 mm/truncate.c:451
>  truncate_inode_pages+0x24/0x30 mm/truncate.c:478
>  swap_inode_boot_loader fs/ext4/ioctl.c:123 [inline]
>  ext4_ioctl+0x1e3b/0x4210 fs/ext4/ioctl.c:865
>  vfs_ioctl fs/ioctl.c:46 [inline]
>  file_ioctl fs/ioctl.c:501 [inline]
>  do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
>  ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
>  __do_sys_ioctl fs/ioctl.c:709 [inline]
>  __se_sys_ioctl fs/ioctl.c:707 [inline]
>  __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
>  do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
>  entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x457579
> Code: 1d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7
> 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff
> 0f 83 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
> RSP: 002b:00007fa151655c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457579
> RDX: 0000000020000000 RSI: 0000000000006611 RDI: 0000000000000006
> RBP: 000000000072bfa0 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa1516566d4
> R13: 00000000004bf60e R14: 00000000004cf4a8 R15: 00000000ffffffff
> Kernel Offset: disabled
> Rebooting in 86400 seconds..
>
>
> ---
> This bug is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
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>
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