Dear Linux Developer, Recently when using our tool to fuzz kernel, the following crash was triggered: HEAD commit: 64570fbc14f8 Linux 5.15-rc5 git tree: upstream compiler: clang 12.0.0 console output: https://drive.google.com/file/d/1EV0R2yutxfhDNK7k-qzCsfy0Y7cRjSxK/view?usp=sharing kernel config: https://drive.google.com/file/d/1lNwvovjLNrcuyFGrg05IoSmgO5jaKBBJ/view?usp=sharing Unfortunately, I don't have any reproducer for this crash yet. 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: 580 Comm: syz-executor Not tainted 5.15.0-rc5 #4 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0010:get_fuse_conn_super fs/fuse/fuse_i.h:844 [inline] RIP: 0010:fuse_test_super+0x68/0xa0 fs/fuse/inode.c:1633 Code: 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 3a 48 8b 9b 78 06 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <80> 3c 02 00 75 12 31 c0 48 39 2b 5b 5d 0f 94 c0 c3 e8 b2 0d 0a ff RSP: 0018:ffffc90008bdfca0 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000040000 RDX: 0000000000000000 RSI: ffff88802329a380 RDI: ffff88800ec68678 RBP: ffff88802a2fc800 R08: ffffffff82b3dfbd R09: fffff5200117bf8a R10: 0000000000000003 R11: fffff5200117bf89 R12: dffffc0000000000 R13: ffffffff82b3dfb0 R14: 0000000000000000 R15: 0000000000000002 FS: 00007ff8f37f0700(0000) GS:ffff888063e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055d548d9cbf0 CR3: 000000004d5c6000 CR4: 0000000000752ef0 DR0: 0000000020000080 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: sget_fc+0x1ff/0x7e0 fs/super.c:525 fuse_get_tree+0x201/0x3f0 fs/fuse/inode.c:1664 vfs_get_tree+0x89/0x2f0 fs/super.c:1498 do_new_mount fs/namespace.c:2988 [inline] path_mount+0x1228/0x1cb0 fs/namespace.c:3318 do_mount+0xf3/0x110 fs/namespace.c:3331 __do_sys_mount fs/namespace.c:3539 [inline] __se_sys_mount fs/namespace.c:3516 [inline] __x64_sys_mount+0x18f/0x230 fs/namespace.c:3516 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: 0033:0x7ff8f62cc5de Code: 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ff8f37efa68 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff8f62cc5de RDX: 00000000200075c0 RSI: 0000000020007600 RDI: 0000000000000000 RBP: 00007ff8f37efb00 R08: 00007ff8f37efb00 R09: 00000000200075c0 R10: 0000000000000004 R11: 0000000000000202 R12: 00000000200075c0 R13: 0000000020007600 R14: 00007ff8f37efac0 R15: 0000000020007600 Modules linked in: Dumping ftrace buffer: (ftrace buffer empty) ---[ end trace 361dd1df065c6dad ]--- RIP: 0010:get_fuse_conn_super fs/fuse/fuse_i.h:844 [inline] RIP: 0010:fuse_test_super+0x68/0xa0 fs/fuse/inode.c:1633 Code: 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 3a 48 8b 9b 78 06 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <80> 3c 02 00 75 12 31 c0 48 39 2b 5b 5d 0f 94 c0 c3 e8 b2 0d 0a ff RSP: 0018:ffffc90008bdfca0 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000040000 RDX: 0000000000000000 RSI: ffff88802329a380 RDI: ffff88800ec68678 RBP: ffff88802a2fc800 R08: ffffffff82b3dfbd R09: fffff5200117bf8a R10: 0000000000000003 R11: fffff5200117bf89 R12: dffffc0000000000 R13: ffffffff82b3dfb0 R14: 0000000000000000 R15: 0000000000000002 FS: 00007ff8f37f0700(0000) GS:ffff888063e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055d548d9cbf0 CR3: 000000004d5c6000 CR4: 0000000000752ef0 DR0: 0000000020000080 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 ---------------- Code disassembly (best guess), 4 bytes skipped: 0: df 48 89 fisttps -0x77(%rax) 3: fa cli 4: 48 c1 ea 03 shr $0x3,%rdx 8: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) c: 75 3a jne 0x48 e: 48 8b 9b 78 06 00 00 mov 0x678(%rbx),%rbx 15: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 1c: fc ff df 1f: 48 89 da mov %rbx,%rdx 22: 48 c1 ea 03 shr $0x3,%rdx * 26: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction 2a: 75 12 jne 0x3e 2c: 31 c0 xor %eax,%eax 2e: 48 39 2b cmp %rbp,(%rbx) 31: 5b pop %rbx 32: 5d pop %rbp 33: 0f 94 c0 sete %al 36: c3 retq 37: e8 b2 0d 0a ff callq 0xff0a0dee Best, Wei
