Re: [syzbot] WARNING in z_erofs_lz4_decompress

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    9ae1fbdeabd3 Add linux-next specific files for 20211025
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1300f7c4b00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=aeb17e42bc109064
dashboard link: https://syzkaller.appspot.com/bug?extid=d8aaffc3719597e8cfb4
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=103ac24ab00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=177194e2b00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d8aaffc3719597e8cfb4@xxxxxxxxxxxxxxxxxxxxxxxxx

erofs: (device loop0): z_erofs_lz4_decompress_mem: failed to decompress -4099 in[4096, 0] out[9000]
------------[ cut here ]------------
WARNING: CPU: 1 PID: 45 at fs/erofs/decompressor.c:230 z_erofs_lz4_decompress_mem fs/erofs/decompressor.c:227 [inline]
WARNING: CPU: 1 PID: 45 at fs/erofs/decompressor.c:230 z_erofs_lz4_decompress+0x841/0x1400 fs/erofs/decompressor.c:289
Modules linked in:
CPU: 1 PID: 45 Comm: kworker/u5:0 Not tainted 5.15.0-rc6-next-20211025-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: erofs_unzipd z_erofs_decompressqueue_work
RIP: 0010:z_erofs_lz4_decompress_mem fs/erofs/decompressor.c:230 [inline]
RIP: 0010:z_erofs_lz4_decompress+0x841/0x1400 fs/erofs/decompressor.c:289
Code: e9 03 80 3c 11 00 0f 85 8c 0a 00 00 41 56 48 8b 7d 00 45 89 e9 89 d9 48 c7 c2 00 f0 fb 89 48 c7 c6 20 f2 fb 89 e8 fc 4a 85 05 <0f> 0b 48 b8 00 00 00 00 00 fc ff df 48 8b 4c 24 08 5f 48 89 ca 48
RSP: 0018:ffffc9000115f710 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffffffffffffeffd RCX: 0000000000000000
RDX: ffff88801599d7c0 RSI: ffffffff815f17d8 RDI: fffff5200022bed2
RBP: ffffc9000115f850 R08: 0000000000000063 R09: 0000000000000000
R10: ffffffff815eb5ae R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000002328 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056199e7f9008 CR3: 000000007f362000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 z_erofs_decompress_pcluster.isra.0+0x1301/0x2250 fs/erofs/zdata.c:975
 z_erofs_decompress_queue fs/erofs/zdata.c:1053 [inline]
 z_erofs_decompressqueue_work+0xe1/0x170 fs/erofs/zdata.c:1064
 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2445
 kthread+0x405/0x4f0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>