Hi, This bug was found in Linux Kernel v4.18-rc2 $ cat report4 ================================================================================ UBSAN: Undefined behaviour in net/core/sock.c:793:19 signed integer overflow: -1704733899 * 2 cannot be represented in type 'int' CPU: 0 PID: 5695 Comm: syz-executor1 Not tainted 4.18.0-rc1 #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x122/0x1c8 lib/dump_stack.c:113 ubsan_epilogue+0x12/0x86 lib/ubsan.c:159 handle_overflow+0x1c2/0x21f lib/ubsan.c:190 __ubsan_handle_mul_overflow+0x2a/0x38 lib/ubsan.c:214 sock_setsockopt+0x17f1/0x1c80 net/core/sock.c:793 __sys_setsockopt+0x23f/0x2a0 net/socket.c:1943 __do_sys_setsockopt net/socket.c:1958 [inline] __se_sys_setsockopt net/socket.c:1955 [inline] __x64_sys_setsockopt+0xcc/0x170 net/socket.c:1955 do_syscall_64+0xb8/0x3a0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x455a09 Code: 1d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 eb b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fb211862c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007fb2118636d4 RCX: 0000000000455a09 RDX: 0000000000000021 RSI: 0000000000000001 RDI: 0000000000000013 RBP: 000000000072bea0 R08: 0000000000000004 R09: 0000000000000000 R10: 0000000020000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000006dc R14: 00000000006ff540 R15: 0000000000000000 ================================================================================ sr 1:0:0:0: [sr0] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE sr 1:0:0:0: [sr0] tag#0 Sense Key : Not Ready [current] sr 1:0:0:0: [sr0] tag#0 Add. Sense: Medium not present sr 1:0:0:0: [sr0] tag#0 CDB: Read(10) 28 00 00 00 00 00 00 00 40 00 print_req_error: I/O error, dev sr0, sector 0 sr 1:0:0:0: [sr0] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE sr 1:0:0:0: [sr0] tag#0 Sense Key : Not Ready [current] sr 1:0:0:0: [sr0] tag#0 Add. Sense: Medium not present sr 1:0:0:0: [sr0] tag#0 CDB: Read(10) 28 00 00 00 00 40 00 00 40 00 print_req_error: I/O error, dev sr0, sector 256 sr 1:0:0:0: [sr0] unaligned transfer sr 1:0:0:0: [sr0] unaligned transfer sr 1:0:0:0: [sr0] unaligned transfer sr 1:0:0:0: [sr0] unaligned transfer sr 1:0:0:0: [sr0] unaligned transfer sr 1:0:0:0: [sr0] unaligned transfer sr 1:0:0:0: [sr0] unaligned transfer sr 1:0:0:0: [sr0] unaligned transfer sr 1:0:0:0: [sr0] unaligned transfer sr 1:0:0:0: [sr0] unaligned transfer sr 1:0:0:0: [sr0] unaligned transfer sr 1:0:0:0: [sr0] unaligned transfer sr 1:0:0:0: [sr0] unaligned transfer sr 1:0:0:0: [sr0] unaligned transfer sr 1:0:0:0: [sr0] unaligned transfer sr 1:0:0:0: [sr0] unaligned transfer sr 1:0:0:0: [sr0] unaligned transfer sr 1:0:0:0: [sr0] unaligned transfer sr 1:0:0:0: [sr0] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE sr 1:0:0:0: [sr0] tag#0 Sense Key : Illegal Request [current] sr 1:0:0:0: [sr0] tag#0 Add. Sense: Invalid command operation code sr 1:0:0:0: [sr0] tag#0 CDB: Write(10) 2a 00 00 00 00 00 00 00 02 00 print_req_error: critical target error, dev sr0, sector 0 Buffer I/O error on dev sr0, logical block 0, lost async page write Buffer I/O error on dev sr0, logical block 1, lost async page write Buffer I/O error on dev sr0, logical block 2, lost async page write Buffer I/O error on dev sr0, logical block 3, lost async page write Buffer I/O error on dev sr0, logical block 4, lost async page write Buffer I/O error on dev sr0, logical block 5, lost async page write Buffer I/O error on dev sr0, logical block 6, lost async page write Buffer I/O error on dev sr0, logical block 7, lost async page write This bug can be repro, if you need it, please tell me. Thanks, Icytxw