bisecting fixing commit since 90c9e950c0def5c354b4a6154a2ddda3e5f214ac building syzkaller on a7dab6385c1d95547a88e22577fb56fbcd5c37eb testing commit 90c9e950c0def5c354b4a6154a2ddda3e5f214ac compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: b5426eb196e847fdc8f524f36e54ad199dc8d3e56b805983f185b29bda1dadbc all runs: crashed: general protection fault in blk_mq_free_rqs testing current HEAD dda64ead7e82caa47fafe0edc36067ee64df2203 testing commit dda64ead7e82caa47fafe0edc36067ee64df2203 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 963c6e86ef99740aa0a7f86e49123abb09d484dd53cf020e03d1bb5487c0a9ee run #0: crashed: general protection fault in blk_mq_free_rqs run #1: crashed: general protection fault in blk_mq_free_rqs run #2: crashed: WARNING in kernfs_remove_by_name_ns run #3: crashed: general protection fault in blk_mq_free_rqs run #4: crashed: general protection fault in blk_mq_free_rqs run #5: crashed: general protection fault in blk_mq_free_rqs run #6: crashed: general protection fault in blk_mq_free_rqs run #7: crashed: WARNING in kernfs_remove_by_name_ns run #8: crashed: general protection fault in blk_mq_free_rqs run #9: crashed: general protection fault in blk_mq_free_rqs revisions tested: 2, total time: 18m46.86074855s (build: 12m21.942935964s, test: 5m53.826681057s) the crash still happens on HEAD commit msg: Merge tag 'trace-v5.17-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace crash: general protection fault in blk_mq_free_rqs 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: 4080 Comm: syz-executor165 Not tainted 5.17.0-rc7-syzkaller #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:3076 [inline] RIP: 0010:blk_mq_free_rqs+0x31e/0x820 block/blk-mq.c:3121 Code: 0f 85 58 03 00 00 48 8b 44 24 20 48 8b 48 28 83 f9 3f 0f 87 9c 95 d0 04 48 8b 44 24 08 41 bc 00 10 00 00 49 d3 e4 4c 03 24 24 <0f> b6 00 4c 89 64 24 10 84 c0 74 08 3c 03 0f 8e 13 03 00 00 48 8b RSP: 0018:ffffc900025bfb28 EFLAGS: 00010286 RAX: dffffc0000000000 RBX: 000000006e770000 RCX: 0000000000000004 RDX: 1ffff1100364cd92 RSI: ffffea0001b9dc00 RDI: ffffea0001b9dc28 RBP: ffff8880190e3800 R08: 0000000000000001 R09: ffffffff8f0bf99f R10: 0000000000000001 R11: 0000000000000246 R12: ffff88806e780000 R13: dffffc0000000000 R14: dffffc0000000000 R15: 0000000000000000 FS: 00007f5b60ede700(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5b60f724d0 CR3: 0000000079943000 CR4: 0000000000350ef0 Call Trace: blk_mq_sched_free_rqs block/blk-mq-sched.c:629 [inline] blk_mq_sched_free_rqs+0x130/0x240 block/blk-mq-sched.c:618 elevator_switch_mq+0xbc/0x530 block/elevator.c:598 blk_mq_elv_switch_none block/blk-mq.c:4460 [inline] __blk_mq_update_nr_hw_queues block/blk-mq.c:4513 [inline] blk_mq_update_nr_hw_queues+0x38b/0xbd0 block/blk-mq.c:4563 nbd_start_device+0x10a/0xb70 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+0x3ba/0x8f0 drivers/block/nbd.c:1511 blkdev_ioctl+0x30b/0x6d0 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+0x11f/0x190 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: 0033:0x7f5b60f31329 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:00007f5b60ede2e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f5b60fb54e0 RCX: 00007f5b60f31329 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000007 RBP: 00007f5b60f82194 R08: 0000000000000002 R09: 0000000000003331 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5b60fb54ec R13: 00007f5b60ede2f0 R14: 00007f5b60fb54e8 R15: 0000000000000002 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:blk_mq_clear_rq_mapping block/blk-mq.c:3076 [inline] RIP: 0010:blk_mq_free_rqs+0x31e/0x820 block/blk-mq.c:3121 Code: 0f 85 58 03 00 00 48 8b 44 24 20 48 8b 48 28 83 f9 3f 0f 87 9c 95 d0 04 48 8b 44 24 08 41 bc 00 10 00 00 49 d3 e4 4c 03 24 24 <0f> b6 00 4c 89 64 24 10 84 c0 74 08 3c 03 0f 8e 13 03 00 00 48 8b RSP: 0018:ffffc900025bfb28 EFLAGS: 00010286 RAX: dffffc0000000000 RBX: 000000006e770000 RCX: 0000000000000004 RDX: 1ffff1100364cd92 RSI: ffffea0001b9dc00 RDI: ffffea0001b9dc28 RBP: ffff8880190e3800 R08: 0000000000000001 R09: ffffffff8f0bf99f R10: 0000000000000001 R11: 0000000000000246 R12: ffff88806e780000 R13: dffffc0000000000 R14: dffffc0000000000 R15: 0000000000000000 FS: 00007f5b60ede700(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5b60f724d0 CR3: 0000000079943000 CR4: 0000000000350ef0 ---------------- Code disassembly (best guess): 0: 0f 85 58 03 00 00 jne 0x35e 6: 48 8b 44 24 20 mov 0x20(%rsp),%rax b: 48 8b 48 28 mov 0x28(%rax),%rcx f: 83 f9 3f cmp $0x3f,%ecx 12: 0f 87 9c 95 d0 04 ja 0x4d095b4 18: 48 8b 44 24 08 mov 0x8(%rsp),%rax 1d: 41 bc 00 10 00 00 mov $0x1000,%r12d 23: 49 d3 e4 shl %cl,%r12 26: 4c 03 24 24 add (%rsp),%r12 * 2a: 0f b6 00 movzbl (%rax),%eax <-- trapping instruction 2d: 4c 89 64 24 10 mov %r12,0x10(%rsp) 32: 84 c0 test %al,%al 34: 74 08 je 0x3e 36: 3c 03 cmp $0x3,%al 38: 0f 8e 13 03 00 00 jle 0x351 3e: 48 rex.W 3f: 8b .byte 0x8b