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: 359d, last: 6d16h

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
Last 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: 3637 Comm: syz-executor392 Not tainted 6.0.0-syzkaller-03015-g2bca25eaeba6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
RIP: 0010:blk_mq_clear_rq_mapping block/blk-mq.c:3040 [inline]
RIP: 0010:blk_mq_free_rqs+0x3f8/0x960 block/blk-mq.c:3088
Code: de e8 ec fa 94 fd 83 fb 3f 0f 87 14 8a 67 05 e8 1e fe 94 fd b8 00 10 00 00 89 d9 48 d3 e0 4c 01 e8 48 89 44 24 08 48 8b 04 24 <0f> b6 00 84 c0 74 08 3c 03 0f 8e 96 03 00 00 41 8b 1f 31 ff 31 ed
RSP: 0018:ffffc9000351faa8 EFLAGS: 00010286
RAX: dffffc0000000000 RBX: 0000000000000004 RCX: 0000000000000004
RDX: ffff88807d2cc100 RSI: ffffffff83e54302 RDI: 0000000000000005
RBP: ffff888021672000 R08: 0000000000000005 R09: 000000000000003f
R10: 0000000000000004 R11: ffff88813fffa700 R12: ffffc9000351fb60
R13: ffff888070470000 R14: ffff888147537000 R15: 0000000000000000
FS:  00007fbc2f35d700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbc2f3e2860 CR3: 00000000747b7000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 blk_mq_sched_free_rqs block/blk-mq-sched.c:642 [inline]
 blk_mq_sched_free_rqs+0x1d4/0x250 block/blk-mq-sched.c:631
 elevator_exit block/elevator.c:196 [inline]
 elevator_switch_mq+0xc2/0x6c0 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+0x3ee/0xdf0 block/blk-mq.c:4594
 nbd_start_device+0x153/0xc30 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+0x5a1/0xbd0 drivers/block/nbd.c:1521
 blkdev_ioctl+0x36e/0x800 block/ioctl.c:614
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
 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+0x63/0xcd
RIP: 0033:0x7fbc2f3b0319
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:00007fbc2f35d2e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fbc2f4344e0 RCX: 00007fbc2f3b0319
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000007
RBP: 00007fbc2f401194 R08: 0000000000000002 R09: 0000000000003331
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fbc2f4344ec
R13: 00007fbc2f35d2f0 R14: 00007fbc2f4344e8 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+0x3f8/0x960 block/blk-mq.c:3088
Code: de e8 ec fa 94 fd 83 fb 3f 0f 87 14 8a 67 05 e8 1e fe 94 fd b8 00 10 00 00 89 d9 48 d3 e0 4c 01 e8 48 89 44 24 08 48 8b 04 24 <0f> b6 00 84 c0 74 08 3c 03 0f 8e 96 03 00 00 41 8b 1f 31 ff 31 ed
RSP: 0018:ffffc9000351faa8 EFLAGS: 00010286
RAX: dffffc0000000000 RBX: 0000000000000004 RCX: 0000000000000004
RDX: ffff88807d2cc100 RSI: ffffffff83e54302 RDI: 0000000000000005
RBP: ffff888021672000 R08: 0000000000000005 R09: 000000000000003f
R10: 0000000000000004 R11: ffff88813fffa700 R12: ffffc9000351fb60
R13: ffff888070470000 R14: ffff888147537000 R15: 0000000000000000
FS:  00007fbc2f35d700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbc2f3f14c0 CR3: 00000000747b7000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	de e8                	fsubrp %st,%st(0)
   2:	ec                   	in     (%dx),%al
   3:	fa                   	cli
   4:	94                   	xchg   %eax,%esp
   5:	fd                   	std
   6:	83 fb 3f             	cmp    $0x3f,%ebx
   9:	0f 87 14 8a 67 05    	ja     0x5678a23
   f:	e8 1e fe 94 fd       	callq  0xfd94fe32
  14:	b8 00 10 00 00       	mov    $0x1000,%eax
  19:	89 d9                	mov    %ebx,%ecx
  1b:	48 d3 e0             	shl    %cl,%rax
  1e:	4c 01 e8             	add    %r13,%rax
  21:	48 89 44 24 08       	mov    %rax,0x8(%rsp)
  26:	48 8b 04 24          	mov    (%rsp),%rax
* 2a:	0f b6 00             	movzbl (%rax),%eax <-- trapping instruction
  2d:	84 c0                	test   %al,%al
  2f:	74 08                	je     0x39
  31:	3c 03                	cmp    $0x3,%al
  33:	0f 8e 96 03 00 00    	jle    0x3cf
  39:	41 8b 1f             	mov    (%r15),%ebx
  3c:	31 ff                	xor    %edi,%edi
  3e:	31 ed                	xor    %ebp,%ebp

Fix bisection attempts:
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci-upstream-kasan-gce-selinux-root 2023/01/26 00:57 upstream 7c46948a6e9c 267e3bb1 .config console log report syz C
ci-upstream-kasan-gce-selinux-root 2022/11/08 01:17 upstream 59f2f4b8a757 267e3bb1 .config console log report syz C
ci-upstream-kasan-gce-root 2022/06/09 16:49 upstream 6bfb56e93bce a7dab638 .config console log report syz C
ci-upstream-kasan-gce-root 2022/05/10 14:01 upstream 9be9ed2612b5 a7dab638 .config console log report syz C
ci-upstream-kasan-gce-root 2022/04/10 03:48 upstream e1f700ebd6be a7dab638 .config console log report syz C
ci-upstream-kasan-gce-root 2022/03/11 03:30 upstream dda64ead7e82 a7dab638 .config console log report syz C
* Struck through repros no longer work on HEAD.
Crashes (14):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci-upstream-kasan-gce-selinux-root 2022/10/05 20:30 upstream 2bca25eaeba6 267e3bb1 .config strace log report syz C [disk image] [vmlinux] general protection fault in blk_mq_free_rqs
ci-upstream-kasan-gce-smack-root 2022/10/03 23:03 upstream 4fe89d07dcc2 feb56351 .config strace log report syz C [disk image] [vmlinux] general protection fault in blk_mq_free_rqs
ci-upstream-kasan-gce-smack-root 2022/09/11 02:49 upstream b96fbd602d35 356d8217 .config strace log report syz C [disk image] [vmlinux] general protection fault in blk_mq_free_rqs
ci-upstream-kasan-gce-root 2022/08/02 16:12 upstream 9de1f9c8ca51 1c9013ac .config strace 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 strace 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 strace 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 strace 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 console 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 strace 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 strace 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 strace 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 console 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 console 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 console log report info general protection fault in blk_mq_free_rqs
* Struck through repros no longer work on HEAD.