From: Jan Kara <jack@suse.cz>
To: syzbot <syzbot+3622cea378100f45d59f@syzkaller.appspotmail.com>
Cc: adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org,
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com,
tytso@mit.edu, linux-mm@kvack.org
Subject: Re: kernel BUG at fs/ext4/inode.c:LINE!
Date: Fri, 28 Aug 2020 12:07:55 +0200 [thread overview]
Message-ID: <20200828100755.GG7072@quack2.suse.cz> (raw)
In-Reply-To: <000000000000d3a33205add2f7b2@google.com>
On Wed 26-08-20 19:48:16, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: c3d8f220 Merge tag 'kbuild-fixes-v5.9' of git://git.kernel..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=15f83cb6900000
> kernel config: https://syzkaller.appspot.com/x/.config?x=bb68b9e8a8cc842f
> dashboard link: https://syzkaller.appspot.com/bug?extid=3622cea378100f45d59f
> compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1287ac96900000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11c7ac46900000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+3622cea378100f45d59f@syzkaller.appspotmail.com
>
> ------------[ cut here ]------------
> kernel BUG at fs/ext4/inode.c:2598!
> invalid opcode: 0000 [#1] PREEMPT SMP KASAN
> CPU: 1 PID: 27612 Comm: syz-executor879 Not tainted 5.9.0-rc1-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> RIP: 0010:mpage_prepare_extent_to_map+0xd34/0xd40 fs/ext4/inode.c:2598
Doh, so this is:
wait_on_page_writeback(page);
>>> BUG_ON(PageWriteback(page));
in mpage_prepare_extent_to_map(). So we have PageWriteback() page after we
have called wait_on_page_writeback() on a locked page. Not sure how this
could ever happen even less how ext4 could cause this...
Anyway, syzbot has found a reproducer so I'll try if it reproduces in my
KVM...
Honza
> Code: 89 e8 a0 74 9f ff 0f 0b e8 59 81 70 ff 4c 89 e7 48 c7 c6 da a3 07 89 e8 8a 74 9f ff 0f 0b e8 43 81 70 ff 0f 0b e8 3c 81 70 ff <0f> 0b e8 c5 b3 25 06 0f 1f 44 00 00 55 41 57 41 56 41 55 41 54 53
> RSP: 0018:ffffc9000a0974d8 EFLAGS: 00010293
> RAX: ffffffff820476e4 RBX: 00fffe000000a01f RCX: ffff88808ea5c340
> RDX: 0000000000000000 RSI: 000000000000a01f RDI: 000000000000ffff
> RBP: ffffea00020d4f80 R08: ffffffff820471e4 R09: fffff9400041a9f1
> R10: fffff9400041a9f1 R11: 0000000000000000 R12: ffffea00020d4f80
> R13: ffffc9000a0977b0 R14: 1ffffd400041a9f1 R15: dffffc0000000000
> FS: 00007f5055f25700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00000000004ae4b0 CR3: 00000000a2d7f000 CR4: 00000000001506e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> ext4_writepages+0xa98/0x3750 fs/ext4/inode.c:2735
> do_writepages+0xda/0x1f0 mm/page-writeback.c:2352
> __filemap_fdatawrite_range+0x2a5/0x350 mm/filemap.c:422
> filemap_write_and_wait_range+0xca/0x160 mm/filemap.c:655
> iomap_dio_rw+0x5a7/0xeb0 fs/iomap/direct-io.c:478
> ext4_dio_read_iter fs/ext4/file.c:77 [inline]
> ext4_file_read_iter+0x544/0x6d0 fs/ext4/file.c:129
> call_read_iter include/linux/fs.h:1876 [inline]
> generic_file_splice_read+0x3c5/0x640 fs/splice.c:312
> do_splice_to fs/splice.c:870 [inline]
> splice_direct_to_actor+0x3bd/0xb60 fs/splice.c:950
> do_splice_direct+0x201/0x340 fs/splice.c:1059
> do_sendfile+0x86d/0x1210 fs/read_write.c:1540
> __do_sys_sendfile64 fs/read_write.c:1601 [inline]
> __se_sys_sendfile64 fs/read_write.c:1587 [inline]
> __x64_sys_sendfile64+0x164/0x1a0 fs/read_write.c:1587
> do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
> RIP: 0033:0x448bc9
> Code: e8 1c e6 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 0b 06 fc ff c3 66 2e 0f 1f 84 00 00 00 00
> RSP: 002b:00007f5055f24ce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
> RAX: ffffffffffffffda RBX: 00000000006e4a28 RCX: 0000000000448bc9
> RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000004
> RBP: 00000000006e4a20 R08: 0000000000000000 R09: 0000000000000000
> R10: 00008400fffffffb R11: 0000000000000246 R12: 00000000006e4a2c
> R13: 00007ffdc73a76df R14: 00007f5055f259c0 R15: 20c49ba5e353f7cf
> Modules linked in:
> ---[ end trace aba5fca59eda2183 ]---
> RIP: 0010:mpage_prepare_extent_to_map+0xd34/0xd40 fs/ext4/inode.c:2598
> Code: 89 e8 a0 74 9f ff 0f 0b e8 59 81 70 ff 4c 89 e7 48 c7 c6 da a3 07 89 e8 8a 74 9f ff 0f 0b e8 43 81 70 ff 0f 0b e8 3c 81 70 ff <0f> 0b e8 c5 b3 25 06 0f 1f 44 00 00 55 41 57 41 56 41 55 41 54 53
> RSP: 0018:ffffc9000a0974d8 EFLAGS: 00010293
> RAX: ffffffff820476e4 RBX: 00fffe000000a01f RCX: ffff88808ea5c340
> RDX: 0000000000000000 RSI: 000000000000a01f RDI: 000000000000ffff
> RBP: ffffea00020d4f80 R08: ffffffff820471e4 R09: fffff9400041a9f1
> R10: fffff9400041a9f1 R11: 0000000000000000 R12: ffffea00020d4f80
> R13: ffffc9000a0977b0 R14: 1ffffd400041a9f1 R15: dffffc0000000000
> FS: 00007f5055f25700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00000000004ae4b0 CR3: 00000000a2d7f000 CR4: 00000000001506e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> syzbot can test patches for this issue, for details see:
> https://goo.gl/tpsmEJ#testing-patches
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next parent reply other threads:[~2020-08-28 10:07 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <000000000000d3a33205add2f7b2@google.com>
2020-08-28 10:07 ` Jan Kara [this message]
2020-08-31 10:03 ` Jan Kara
2020-08-31 18:21 ` Linus Torvalds
2020-11-24 4:07 ` Hugh Dickins
2020-11-24 4:26 ` Linus Torvalds
2020-11-24 4:53 ` Linus Torvalds
2020-11-24 6:34 ` Hugh Dickins
2020-11-24 16:46 ` Hugh Dickins
2020-11-24 12:19 ` Matthew Wilcox
2020-11-24 16:28 ` Hugh Dickins
2020-11-24 18:33 ` Matthew Wilcox
2020-11-24 19:00 ` Linus Torvalds
2020-11-24 20:15 ` Matthew Wilcox
2020-11-24 20:34 ` Linus Torvalds
2020-11-24 21:46 ` Hugh Dickins
2020-11-24 23:24 ` Linus Torvalds
2020-11-25 21:30 ` Linus Torvalds
2020-11-25 22:01 ` Linus Torvalds
2020-11-25 9:20 ` Jan Kara
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