Good day, dear maintainers, We found a bug using a modified kernel configuration file used by syzbot. We enhanced the coverage of the configuration file using our tool, klocalizer. Kernel Branch: 6.2.0-rc7-next-20230213 Kernel config: https://drive.google.com/file/d/1yVvlPL4-MMdjARqrwJ0QoKuPv_3lFQIR/view?usp=share_link Unfortunately, we do not have a reproducer yet. Thank you! Best regards, Sanan Hasanov general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 1 PID: 10907 Comm: syz-executor.3 Not tainted 6.2.0-rc7-next-20230213+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:blkg_destroy_all+0xa5/0x260 Code: 7d c0 e8 7e 65 27 06 48 8b 45 b8 80 38 00 0f 85 a8 01 00 00 48 8b 45 c8 48 8b 98 80 05 00 00 4c 8d 63 f8 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 0f 85 7a 01 00 00 48 8b 03 48 39 5d d0 4c 8d 78 f8 RSP: 0018:ffffc9001ca5fcb8 EFLAGS: 00010056 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8168f15d RDX: 1ffff11021b6cc29 RSI: 0000000000000004 RDI: ffffc9001ca5fc18 RBP: ffffc9001ca5fd08 R08: 0000000000000001 R09: 0000000000000003 R10: fffff5200394bf83 R11: 0000000000000001 R12: fffffffffffffff8 R13: dffffc0000000000 R14: ffffffff8ae21700 R15: ffff888080ff1090 FS: 00007f21d3837700(0000) GS:ffff88811a080000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb7b4ffcbd8 CR3: 00000001118c3000 CR4: 0000000000350ee0 Call Trace: <TASK> blkcg_exit_disk+0x1a/0x60 disk_release+0xec/0x4a0 device_release+0xae/0x250 kobject_put+0x1d8/0x2c0 put_device+0x24/0x30 put_disk+0x49/0x60 loop_add+0x91f/0xb20 loop_control_ioctl+0x13d/0x690 __x64_sys_ioctl+0x1a9/0x220 do_syscall_64+0x39/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f21d268edcd Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 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:00007f21d3836bf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f21d27bbf80 RCX: 00007f21d268edcd RDX: 0000000000000000 RSI: 0000000000004c80 RDI: 0000000000000004 RBP: 00007f21d26fc59c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc7837a81f R14: 00007ffc7837a9c0 R15: 00007f21d3836d80 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:blkg_destroy_all+0xa5/0x260 Code: 7d c0 e8 7e 65 27 06 48 8b 45 b8 80 38 00 0f 85 a8 01 00 00 48 8b 45 c8 48 8b 98 80 05 00 00 4c 8d 63 f8 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 0f 85 7a 01 00 00 48 8b 03 48 39 5d d0 4c 8d 78 f8 RSP: 0018:ffffc9001ca5fcb8 EFLAGS: 00010056 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8168f15d RDX: 1ffff11021b6cc29 RSI: 0000000000000004 RDI: ffffc9001ca5fc18 RBP: ffffc9001ca5fd08 R08: 0000000000000001 R09: 0000000000000003 R10: fffff5200394bf83 R11: 0000000000000001 R12: fffffffffffffff8 R13: dffffc0000000000 R14: ffffffff8ae21700 R15: ffff888080ff1090 FS: 00007f21d3837700(0000) GS:ffff88811a080000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb7b4ffcbd8 CR3: 00000001118c3000 CR4: 0000000000350ee0 ---------------- Code disassembly (best guess): 0: 7d c0 jge 0xffffffc2 2: e8 7e 65 27 06 call 0x6276585 7: 48 8b 45 b8 mov -0x48(%rbp),%rax b: 80 38 00 cmpb $0x0,(%rax) e: 0f 85 a8 01 00 00 jne 0x1bc 14: 48 8b 45 c8 mov -0x38(%rbp),%rax 18: 48 8b 98 80 05 00 00 mov 0x580(%rax),%rbx 1f: 4c 8d 63 f8 lea -0x8(%rbx),%r12 23: 48 89 d8 mov %rbx,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) <-- trapping instruction 2f: 0f 85 7a 01 00 00 jne 0x1af 35: 48 8b 03 mov (%rbx),%rax 38: 48 39 5d d0 cmp %rbx,-0x30(%rbp) 3c: 4c 8d 78 f8 lea -0x8(%rax),%r15
