Re: [syzbot] kernel BUG at fs/ext4/inline.c:LINE!

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    2585cf9dfaad Linux 5.16-rc5
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1034be69b00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=44af4fa322f7642f
dashboard link: https://syzkaller.appspot.com/bug?extid=4faa160fa96bfba639f8
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=148458d1b00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=110f6169b00000

Bisection is inconclusive: the issue happens on the oldest tested release.

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=119be2ab900000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=139be2ab900000
console output: https://syzkaller.appspot.com/x/log.txt?x=159be2ab900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4faa160fa96bfba639f8@xxxxxxxxxxxxxxxxxxxxxxxxx

------------[ cut here ]------------
kernel BUG at fs/ext4/inline.c:755!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 3633 Comm: syz-executor843 Not tainted 5.16.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:ext4_write_inline_data_end+0xa11/0x1120 fs/ext4/inline.c:755
Code: 01 44 89 f6 e8 40 dc 67 ff 41 83 fe 01 0f 87 2a fb ff ff e8 11 da 67 ff 4c 89 e7 e8 79 fe 90 ff e9 9e fb ff ff e8 ff d9 67 ff <0f> 0b e8 f8 d9 67 ff 4c 89 e2 48 b8 00 00 00 00 00 fc ff df 48 c1
RSP: 0018:ffffc9000281f3a8 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: ffff888076750000 RSI: ffffffff820fd161 RDI: 0000000000000003
RBP: ffff8880737a5c58 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff820fc907 R11: 0000000000000000 R12: ffffea0001f0d640
R13: 0000000000000001 R14: ffff8880737a5a08 R15: ffffc9000281f400
FS:  00007f57f9ace700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c0556fbf48 CR3: 000000007a16f000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 ext4_write_end+0x200/0xcf0 fs/ext4/inode.c:1292
 ext4_da_write_end+0x375/0x990 fs/ext4/inode.c:3026
 generic_perform_write+0x2c6/0x510 mm/filemap.c:3765
 ext4_buffered_write_iter+0x1ac/0x3b0 fs/ext4/file.c:269
 ext4_file_write_iter+0x423/0x14e0 fs/ext4/file.c:681
 call_write_iter include/linux/fs.h:2162 [inline]
 do_iter_readv_writev+0x472/0x750 fs/read_write.c:725
 do_iter_write+0x188/0x710 fs/read_write.c:851
 vfs_iter_write+0x70/0xa0 fs/read_write.c:892
 iter_file_splice_write+0x723/0xc70 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x110/0x180 fs/splice.c:936
 splice_direct_to_actor+0x34b/0x8c0 fs/splice.c:891
 do_splice_direct+0x1b3/0x280 fs/splice.c:979
 do_sendfile+0xaf2/0x1250 fs/read_write.c:1245
 __do_sys_sendfile64 fs/read_write.c:1310 [inline]
 __se_sys_sendfile64 fs/read_write.c:1296 [inline]
 __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1296
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f57f9b21de9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f57f9ace2f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f57f9ba74c0 RCX: 00007f57f9b21de9
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000003
RBP: 00007f57f9b740cc R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000010000 R11: 0000000000000246 R12: 0030656c69662f2e
R13: 00007f57f9b730c8 R14: 0000000300000002 R15: 00007f57f9ba74c8
 </TASK>
Modules linked in:
---[ end trace e6a45f74f6d725ce ]---
RIP: 0010:ext4_write_inline_data_end+0xa11/0x1120 fs/ext4/inline.c:755
Code: 01 44 89 f6 e8 40 dc 67 ff 41 83 fe 01 0f 87 2a fb ff ff e8 11 da 67 ff 4c 89 e7 e8 79 fe 90 ff e9 9e fb ff ff e8 ff d9 67 ff <0f> 0b e8 f8 d9 67 ff 4c 89 e2 48 b8 00 00 00 00 00 fc ff df 48 c1
RSP: 0018:ffffc9000281f3a8 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: ffff888076750000 RSI: ffffffff820fd161 RDI: 0000000000000003
RBP: ffff8880737a5c58 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff820fc907 R11: 0000000000000000 R12: ffffea0001f0d640
R13: 0000000000000001 R14: ffff8880737a5a08 R15: ffffc9000281f400
FS:  00007f57f9ace700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f57f9aad718 CR3: 000000007a16f000 CR4: 0000000000350ef0