Hello, syzbot found the following issue on: HEAD commit: 90c9e950c0de Merge tag 'for-linus-5.17a-rc3-tag' of git://.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=137905dc700000 kernel config: https://syzkaller.appspot.com/x/.config?x=ee3797346aa03884 dashboard link: https://syzkaller.appspot.com/bug?extid=7295389ef2000630244b 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=10801462700000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=135d7524700000 Bisection is inconclusive: the issue happens on the oldest tested release. bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=14b09d42700000 final oops: https://syzkaller.appspot.com/x/report.txt?x=16b09d42700000 console output: https://syzkaller.appspot.com/x/log.txt?x=12b09d42700000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+7295389ef2000630244b@xxxxxxxxxxxxxxxxxxxxxxxxx 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: 3605 Comm: syz-executor139 Not tainted 5.17.0-rc2-syzkaller-00353-g90c9e950c0de #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:blk_mq_clear_rq_mapping block/blk-mq.c:3061 [inline] RIP: 0010:blk_mq_free_rqs+0x399/0x910 block/blk-mq.c:3106 Code: de e8 8b 83 ac fd 83 fb 3f 0f 87 04 c3 49 05 e8 5d 81 ac 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 bb 03 00 00 41 8b 1f 31 ff 31 ed RSP: 0018:ffffc900027afaf8 EFLAGS: 00010286 RAX: dffffc0000000000 RBX: 0000000000000004 RCX: 0000000000000004 RDX: ffff888074ef3a00 RSI: ffffffff83cbf733 RDI: 0000000000000003 RBP: ffff888071ce6000 R08: 000000000000003f R09: ffffffff8ffbf99f R10: ffffffff83cbf725 R11: 0000000000000246 R12: dffffc0000000000 R13: ffff88801a380000 R14: ffff88801a23f000 R15: 0000000000000000 FS: 00007f894cb64700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f894cc20aa3 CR3: 0000000021f45000 CR4: 0000000000350ef0 Call Trace: <TASK> blk_mq_sched_free_rqs block/blk-mq-sched.c:629 [inline] blk_mq_sched_free_rqs+0x16c/0x270 block/blk-mq-sched.c:618 elevator_switch_mq+0xed/0x720 block/elevator.c:600 blk_mq_elv_switch_none block/blk-mq.c:4445 [inline] __blk_mq_update_nr_hw_queues block/blk-mq.c:4498 [inline] blk_mq_update_nr_hw_queues+0x3f1/0xd30 block/blk-mq.c:4548 nbd_start_device+0x157/0xd10 drivers/block/nbd.c:1347 nbd_start_device_ioctl drivers/block/nbd.c:1397 [inline] __nbd_ioctl drivers/block/nbd.c:1471 [inline] nbd_ioctl+0x5f3/0xb10 drivers/block/nbd.c:1511 blkdev_ioctl+0x37a/0x800 block/ioctl.c:588 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 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: 0033:0x7f894cbb7349 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:00007f894cb642e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f894cc3c4e0 RCX: 00007f894cbb7349 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000007 RBP: 00007f894cc091ac R08: 0000000000000002 R09: 0000000000003331 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f894cc3c4ec R13: 00007f894cb642f0 R14: 00007f894cc3c4e8 R15: 0000000000000002 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:blk_mq_clear_rq_mapping block/blk-mq.c:3061 [inline] RIP: 0010:blk_mq_free_rqs+0x399/0x910 block/blk-mq.c:3106 Code: de e8 8b 83 ac fd 83 fb 3f 0f 87 04 c3 49 05 e8 5d 81 ac 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 bb 03 00 00 41 8b 1f 31 ff 31 ed RSP: 0018:ffffc900027afaf8 EFLAGS: 00010286 RAX: dffffc0000000000 RBX: 0000000000000004 RCX: 0000000000000004 RDX: ffff888074ef3a00 RSI: ffffffff83cbf733 RDI: 0000000000000003 RBP: ffff888071ce6000 R08: 000000000000003f R09: ffffffff8ffbf99f R10: ffffffff83cbf725 R11: 0000000000000246 R12: dffffc0000000000 R13: ffff88801a380000 R14: ffff88801a23f000 R15: 0000000000000000 FS: 00007f894cb64700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f894cc20aa3 CR3: 0000000021f45000 CR4: 0000000000350ef0 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: e8 8b 83 ac fd callq 0xfdac8390 5: 83 fb 3f cmp $0x3f,%ebx 8: 0f 87 04 c3 49 05 ja 0x549c312 e: e8 5d 81 ac fd callq 0xfdac8170 13: b8 00 10 00 00 mov $0x1000,%eax 18: 89 d9 mov %ebx,%ecx 1a: 48 d3 e0 shl %cl,%rax 1d: 4c 01 e8 add %r13,%rax 20: 48 89 44 24 08 mov %rax,0x8(%rsp) 25: 48 8b 04 24 mov (%rsp),%rax * 29: 0f b6 00 movzbl (%rax),%eax <-- trapping instruction 2c: 84 c0 test %al,%al 2e: 74 08 je 0x38 30: 3c 03 cmp $0x3,%al 32: 0f 8e bb 03 00 00 jle 0x3f3 38: 41 8b 1f mov (%r15),%ebx 3b: 31 ff xor %edi,%edi 3d: 31 ed xor %ebp,%ebp --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches
