syzbot


general protection fault in blk_mq_free_rqs

Status: upstream: reported C repro on 2022/02/10 19:17
Reported-by: syzbot+7295389ef2000630244b@syzkaller.appspotmail.com
First crash: 239d, last: 22d

Cause bisection: the issue happens on the oldest tested release (bisect log)
Crash: WARNING in kernfs_remove_by_name_ns (log)
Repro: C syz .config
Patch testing requests:
Created Duration User Patch Repo Result
2022/07/06 04:50 11m gautammenghani201@gmail.com upstream report log

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 3632 Comm: syz-executor426 Not tainted 6.0.0-rc4-syzkaller-00302-gb96fbd602d35 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
RIP: 0010:blk_mq_clear_rq_mapping block/blk-mq.c:3040 [inline]
RIP: 0010:blk_mq_free_rqs+0x3ef/0x830 block/blk-mq.c:3088
Code: 89 de e8 f4 b3 6d fd 83 fb 3f 48 89 6c 24 18 0f 87 2e 02 00 00 e8 c1 af 6d fd bb 00 10 00 00 44 89 e1 48 d3 e3 48 8b 44 24 28 <42> 8a 04 30 84 c0 0f 85 ed 01 00 00 48 8b 04 24 8b 28 31 ff 89 ee
RSP: 0018:ffffc9000391f9e0 EFLAGS: 00010206
RAX: 0000000000000000 RBX: 0000000000010000 RCX: 0000000000000004
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000040
RBP: ffffea0001cc3008 R08: ffffffff841be82c R09: fffffbfff1c4b476
R10: fffffbfff1c4b476 R11: 1ffffffff1c4b475 R12: 0000000000000004
R13: 1ffff110040bf492 R14: dffffc0000000000 R15: 0000000000000080
FS:  00007f1c14cbc700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1c14c9aec8 CR3: 000000001c7c3000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 blk_mq_sched_free_rqs+0x1b0/0x2a0 block/blk-mq-sched.c:642
 elevator_exit block/elevator.c:196 [inline]
 elevator_switch_mq+0x1db/0x6d0 block/elevator.c:600
 blk_mq_elv_switch_none block/blk-mq.c:4483 [inline]
 __blk_mq_update_nr_hw_queues block/blk-mq.c:4543 [inline]
 blk_mq_update_nr_hw_queues+0x5c8/0x12d0 block/blk-mq.c:4594
 nbd_start_device+0x15d/0xb70 drivers/block/nbd.c:1357
 nbd_start_device_ioctl drivers/block/nbd.c:1407 [inline]
 __nbd_ioctl drivers/block/nbd.c:1481 [inline]
 nbd_ioctl+0x3b3/0xa40 drivers/block/nbd.c:1521
 blkdev_ioctl+0x3a6/0x760 block/ioctl.c:614
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f1c14d0f319
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1c14cbc2e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f1c14d934e0 RCX: 00007f1c14d0f319
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000007
RBP: 00007f1c14d60194 R08: 0000000000000002 R09: 0000000000003331
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f1c14d934ec
R13: 00007f1c14cbc2f0 R14: 00007f1c14d934e8 R15: 0000000000000002
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:blk_mq_clear_rq_mapping block/blk-mq.c:3040 [inline]
RIP: 0010:blk_mq_free_rqs+0x3ef/0x830 block/blk-mq.c:3088
Code: 89 de e8 f4 b3 6d fd 83 fb 3f 48 89 6c 24 18 0f 87 2e 02 00 00 e8 c1 af 6d fd bb 00 10 00 00 44 89 e1 48 d3 e3 48 8b 44 24 28 <42> 8a 04 30 84 c0 0f 85 ed 01 00 00 48 8b 04 24 8b 28 31 ff 89 ee
RSP: 0018:ffffc9000391f9e0 EFLAGS: 00010206
RAX: 0000000000000000 RBX: 0000000000010000 RCX: 0000000000000004
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000040
RBP: ffffea0001cc3008 R08: ffffffff841be82c R09: fffffbfff1c4b476
R10: fffffbfff1c4b476 R11: 1ffffffff1c4b475 R12: 0000000000000004
R13: 1ffff110040bf492 R14: dffffc0000000000 R15: 0000000000000080
FS:  00007f1c14cbc700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1c14d504c0 CR3: 000000001c7c3000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	89 de                	mov    %ebx,%esi
   2:	e8 f4 b3 6d fd       	callq  0xfd6db3fb
   7:	83 fb 3f             	cmp    $0x3f,%ebx
   a:	48 89 6c 24 18       	mov    %rbp,0x18(%rsp)
   f:	0f 87 2e 02 00 00    	ja     0x243
  15:	e8 c1 af 6d fd       	callq  0xfd6dafdb
  1a:	bb 00 10 00 00       	mov    $0x1000,%ebx
  1f:	44 89 e1             	mov    %r12d,%ecx
  22:	48 d3 e3             	shl    %cl,%rbx
  25:	48 8b 44 24 28       	mov    0x28(%rsp),%rax
* 2a:	42 8a 04 30          	mov    (%rax,%r14,1),%al <-- trapping instruction
  2e:	84 c0                	test   %al,%al
  30:	0f 85 ed 01 00 00    	jne    0x223
  36:	48 8b 04 24          	mov    (%rsp),%rax
  3a:	8b 28                	mov    (%rax),%ebp
  3c:	31 ff                	xor    %edi,%edi
  3e:	89 ee                	mov    %ebp,%esi

Fix bisection attempts:
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-root 2022/06/09 16:49 upstream 6bfb56e93bce a7dab638 .config log report syz C
ci-upstream-kasan-gce-root 2022/05/10 14:01 upstream 9be9ed2612b5 a7dab638 .config log report syz C
ci-upstream-kasan-gce-root 2022/04/10 03:48 upstream e1f700ebd6be a7dab638 .config log report syz C
ci-upstream-kasan-gce-root 2022/03/11 03:30 upstream dda64ead7e82 a7dab638 .config log report syz C
* Struck through repros no longer work on HEAD.
Crashes (12):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-smack-root 2022/09/11 02:49 upstream b96fbd602d35 356d8217 .config log report syz C general protection fault in blk_mq_free_rqs
ci-upstream-kasan-gce-root 2022/08/02 16:12 upstream 9de1f9c8ca51 1c9013ac .config log report syz C general protection fault in blk_mq_free_rqs
ci-upstream-kasan-gce-selinux-root 2022/07/27 03:44 upstream 5de64d44968e 279b89c2 .config log report syz C general protection fault in blk_mq_free_rqs
ci-upstream-kasan-gce-root 2022/07/16 09:44 upstream 9b59ec8d50a1 95cb00d1 .config log report syz C general protection fault in blk_mq_free_rqs
ci-upstream-kasan-gce-smack-root 2022/06/25 10:57 upstream 6a0a17e6c6d1 a371c43c .config log report syz C general protection fault in blk_mq_free_rqs
ci-upstream-kasan-gce-root 2022/02/06 19:27 upstream 90c9e950c0de a7dab638 .config log report syz C general protection fault in blk_mq_free_rqs
ci-upstream-linux-next-kasan-gce-root 2022/08/26 18:21 linux-next 8d0c42c9e807 e5a303f1 .config log report syz C general protection fault in blk_mq_free_rqs
ci-upstream-linux-next-kasan-gce-root 2022/06/27 05:41 linux-next 2f9cb3d3bd73 a371c43c .config log report syz C general protection fault in blk_mq_free_rqs
ci-upstream-linux-next-kasan-gce-root 2022/06/25 19:36 linux-next 2f9cb3d3bd73 a371c43c .config log report syz C general protection fault in blk_mq_free_rqs
ci-upstream-kasan-gce-selinux-root 2022/08/07 13:28 upstream 200e340f2196 88e3a122 .config log report info general protection fault in blk_mq_free_rqs
ci-upstream-kasan-gce-root 2022/02/09 03:11 upstream e6251ab4551f 0b33604d .config log report info general protection fault in blk_mq_free_rqs
ci-upstream-kasan-gce-root 2022/02/06 19:11 upstream 90c9e950c0de a7dab638 .config log report info general protection fault in blk_mq_free_rqs
* Struck through repros no longer work on HEAD.