general protection fault, probably for non-canonical address 0xdffffc000000000c: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000060-0x0000000000000067] CPU: 0 PID: 371 Comm: syz-executor270 Not tainted 5.10.117-syzkaller-00814-gfdd06dc6b0f8 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:cdev_get fs/char_dev.c:350 [inline] RIP: 0010:chrdev_open+0xb3/0x680 fs/char_dev.c:400 Code: 00 4c 89 fb 48 c1 eb 03 42 80 3c 33 00 74 08 4c 89 ff e8 50 25 f7 ff 4d 8b 2f 4d 85 ed 74 40 49 8d 5d 60 48 89 d8 48 c1 e8 03 <42> 80 3c 30 00 74 08 48 89 df e8 2e 25 f7 ff 48 8b 1b 48 85 db 0f RSP: 0018:ffffc90000c077a0 EFLAGS: 00010206 RAX: 000000000000000c RBX: 0000000000000062 RCX: 0000000000000001 RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90000c07720 RBP: ffffc90000c07880 R08: dffffc0000000000 R09: 0000000000000003 R10: fffff52000180ee5 R11: 1ffff92000180ee4 R12: 1ffff92000180efc R13: 0000000000000002 R14: dffffc0000000000 R15: ffff8881199fdbc0 FS: 00005555564453c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f652f57e6a8 CR3: 00000001061ab000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: do_dentry_open+0x7a2/0x1090 fs/open.c:819 vfs_open+0x73/0x80 fs/open.c:942 do_open fs/namei.c:3327 [inline] path_openat+0x2638/0x2fd0 fs/namei.c:3444 do_filp_open+0x200/0x440 fs/namei.c:3471 do_sys_openat2+0x13b/0x470 fs/open.c:1211 do_sys_open fs/open.c:1227 [inline] __do_sys_open fs/open.c:1235 [inline] __se_sys_open fs/open.c:1231 [inline] __x64_sys_open+0x221/0x270 fs/open.c:1231 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f7969805909 Code: 28 c3 e8 5a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 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 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fffdc1184c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007fffdc1184d8 RCX: 00007f7969805909 RDX: 0000000000000034 RSI: 0000000000080082 RDI: 0000000020000040 RBP: 00007fffdc1184d0 R08: 00007f79697c3bd0 R09: 00007f79697c3bd0 R10: 00007f79697c3bd0 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Modules linked in: ---[ end trace 0fd24476f99204e4 ]--- RIP: 0010:cdev_get fs/char_dev.c:350 [inline] RIP: 0010:chrdev_open+0xb3/0x680 fs/char_dev.c:400 Code: 00 4c 89 fb 48 c1 eb 03 42 80 3c 33 00 74 08 4c 89 ff e8 50 25 f7 ff 4d 8b 2f 4d 85 ed 74 40 49 8d 5d 60 48 89 d8 48 c1 e8 03 <42> 80 3c 30 00 74 08 48 89 df e8 2e 25 f7 ff 48 8b 1b 48 85 db 0f RSP: 0018:ffffc90000c077a0 EFLAGS: 00010206 RAX: 000000000000000c RBX: 0000000000000062 RCX: 0000000000000001 RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90000c07720 RBP: ffffc90000c07880 R08: dffffc0000000000 R09: 0000000000000003 R10: fffff52000180ee5 R11: 1ffff92000180ee4 R12: 1ffff92000180efc R13: 0000000000000002 R14: dffffc0000000000 R15: ffff8881199fdbc0 FS: 00005555564453c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f652f57e6a8 CR3: 00000001061ab000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 00 4c 89 fb add %cl,-0x5(%rcx,%rcx,4) 4: 48 c1 eb 03 shr $0x3,%rbx 8: 42 80 3c 33 00 cmpb $0x0,(%rbx,%r14,1) d: 74 08 je 0x17 f: 4c 89 ff mov %r15,%rdi 12: e8 50 25 f7 ff callq 0xfff72567 17: 4d 8b 2f mov (%r15),%r13 1a: 4d 85 ed test %r13,%r13 1d: 74 40 je 0x5f 1f: 49 8d 5d 60 lea 0x60(%r13),%rbx 23: 48 89 d8 mov %rbx,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1) <-- trapping instruction 2f: 74 08 je 0x39 31: 48 89 df mov %rbx,%rdi 34: e8 2e 25 f7 ff callq 0xfff72567 39: 48 8b 1b mov (%rbx),%rbx 3c: 48 85 db test %rbx,%rbx 3f: 0f .byte 0xf