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Date:   Mon, 10 Apr 2023 02:26:23 -0700
In-Reply-To: <90d29dc6-39b3-439c-904b-7a2207610d64@linux.alibaba.com>
Message-ID: <000000000000ebd27d05f8f7f713@google.com>
Subject: Re: [syzbot] [erofs?] WARNING in rmqueue
From:   syzbot <syzbot+aafb3f37cfeb6534c4ac@syzkaller.appspotmail.com>
To:     hsiangkao@linux.alibaba.com, linux-erofs@lists.ozlabs.org,
        linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com,
        xiang@kernel.org
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Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: unable to handle kernel paging request in z_erofs_decompress_queue

BUG: unable to handle page fault for address: fffff52101a3fff9
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 23ffed067 P4D 23ffed067 PUD 0 
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 4398 Comm: kworker/u5:1 Not tainted 6.3.0-rc6-syzkaller-g09a9639e56c0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023
Workqueue: erofs_worker z_erofs_decompressqueue_work
RIP: 0010:z_erofs_decompress_queue+0xb7e/0x2b40
Code: 0a 48 8b 7c 24 68 e8 51 fe 00 fe 89 db 48 c1 e3 03 48 03 9c 24 20 03 00 00 49 89 de 49 c1 ee 03 48 b8 00 00 00 00 00 fc ff df <41> 80 3c 06 00 74 08 48 89 df e8 23 fe 00 fe 48 83 3b 00 0f 84 a1
RSP: 0018:ffffc90006a5f7c0 EFLAGS: 00010a06
RAX: dffffc0000000000 RBX: ffffc9080d1fffc8 RCX: 1ffff92000d4bf5c
RDX: ffff88802b800000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90006a5fbb0 R08: ffffffff83ddecfa R09: fffff52001a40000
R10: 0000000000000000 R11: dffffc0000000001 R12: 00000000ffff8f00
R13: ffff888073fad0b8 R14: 1ffff92101a3fff9 R15: ffffea0001b54b40
FS:  0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffff52101a3fff9 CR3: 000000002b4b9000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 z_erofs_decompressqueue_work+0x99/0xe0
 process_one_work+0x8f6/0x1170
 worker_thread+0xa63/0x1210
 kthread+0x270/0x300
 ret_from_fork+0x1f/0x30
 </TASK>
Modules linked in:
CR2: fffff52101a3fff9
---[ end trace 0000000000000000 ]---
RIP: 0010:z_erofs_decompress_queue+0xb7e/0x2b40
Code: 0a 48 8b 7c 24 68 e8 51 fe 00 fe 89 db 48 c1 e3 03 48 03 9c 24 20 03 00 00 49 89 de 49 c1 ee 03 48 b8 00 00 00 00 00 fc ff df <41> 80 3c 06 00 74 08 48 89 df e8 23 fe 00 fe 48 83 3b 00 0f 84 a1
RSP: 0018:ffffc90006a5f7c0 EFLAGS: 00010a06
RAX: dffffc0000000000 RBX: ffffc9080d1fffc8 RCX: 1ffff92000d4bf5c
RDX: ffff88802b800000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90006a5fbb0 R08: ffffffff83ddecfa R09: fffff52001a40000
R10: 0000000000000000 R11: dffffc0000000001 R12: 00000000ffff8f00
R13: ffff888073fad0b8 R14: 1ffff92101a3fff9 R15: ffffea0001b54b40
FS:  0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffff52101a3fff9 CR3: 000000002b4b9000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	48 8b 7c 24 68       	mov    0x68(%rsp),%rdi
   5:	e8 51 fe 00 fe       	callq  0xfe00fe5b
   a:	89 db                	mov    %ebx,%ebx
   c:	48 c1 e3 03          	shl    $0x3,%rbx
  10:	48 03 9c 24 20 03 00 	add    0x320(%rsp),%rbx
  17:	00
  18:	49 89 de             	mov    %rbx,%r14
  1b:	49 c1 ee 03          	shr    $0x3,%r14
  1f:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  26:	fc ff df
* 29:	41 80 3c 06 00       	cmpb   $0x0,(%r14,%rax,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	48 89 df             	mov    %rbx,%rdi
  33:	e8 23 fe 00 fe       	callq  0xfe00fe5b
  38:	48 83 3b 00          	cmpq   $0x0,(%rbx)
  3c:	0f                   	.byte 0xf
  3d:	84                   	.byte 0x84
  3e:	a1                   	.byte 0xa1


Tested on:

commit:         09a9639e Linux 6.3-rc6
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/ v6.3-rc6
console output: https://syzkaller.appspot.com/x/log.txt?x=1125d353c80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=174dd96f08254844
dashboard link: https://syzkaller.appspot.com/bug?extid=aafb3f37cfeb6534c4ac
compiler:       Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

Note: no patches were applied.