Bug 200189

$ cat report1 
================================================================================
UBSAN: Undefined behaviour in kernel/time/posix-timers.c:705:20
signed integer overflow:
-1863446814 + -1863446813 cannot be represented in type 'int'
CPU: 0 PID: 22602 Comm: syz-executor0 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_add_overflow+0x2a/0x31 lib/ubsan.c:198
 common_timer_get+0x55a/0x670 kernel/time/posix-timers.c:705
 common_timer_set+0x68/0x570 kernel/time/posix-timers.c:843
 do_timer_settime+0x255/0x350 kernel/time/posix-timers.c:896
 __do_sys_timer_settime kernel/time/posix-timers.c:922 [inline]
 __se_sys_timer_settime kernel/time/posix-timers.c:908 [inline]
 __x64_sys_timer_settime+0x1a0/0x270 kernel/time/posix-timers.c:908
 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:00007f0a707b8c68 EFLAGS: 00000246 ORIG_RAX: 00000000000000df
RAX: ffffffffffffffda RBX: 00007f0a707b96d4 RCX: 0000000000455a09
RDX: 0000000020000200 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 000000000072bf50 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000240 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000793 R14: 0000000000700668 R15: 0000000000000001
================================================================================
FAT-fs (loop0): invalid media value (0xd0)
FAT-fs (loop0): Can't find a valid FAT filesystem
sr 1:0:0:0: [sr0] unaligned transfer
sr 1:0:0:0: [sr0] unaligned transfer
rpcbind: RPC call returned error 22
rpcbind: RPC call returned error 22