On Fri, 10 Mar 2017, Meelis Roos wrote:
Cc'ing KASAN folks
> (Retry with fixed address ox 86 list)
>
> This HP Netserver LT6000R, quad P3 Xeon. Trying
> 4.11.0-rc1-00088-gec3b93a, I got the following UBSAN warning that was
> not there in 4.10:
>
> [ 14.820437]
> ================================================================================
> [ 14.820534] UBSAN: Undefined behaviour in kernel/time/tick-sched.c:600:9
> [ 14.820594] signed integer overflow:
> [ 14.820645] 11567464533 + 3985952 cannot be represented in type 'long long
> int'
This does not make any sense:
11567464533 + 3985952 = 0x2b1798055 + 0x3cd220 = 0x2b1b65275
which definitely fits into a 'long long int' aka 64 bit
> [ 14.820722] CPU: 3 PID: 135 Comm: startpar Not tainted
> 4.11.0-rc1-00088-gec3b93a #61
> [ 14.820793] Hardware name: Hewlett Packard HP NetServer/HP System Board,
> BIOS 4.06.46 PW 06/25/2003
> [ 14.820863] Call Trace:
> [ 14.820950] ? dump_stack+0x45/0x6e
> [ 14.821022] ? ubsan_epilogue+0xb/0x40
> [ 14.821081] ? handle_overflow+0xb6/0xe0
> [ 14.821146] ? smp_trace_apic_timer_interrupt+0x85/0x100
> [ 14.821208] ? __ubsan_handle_add_overflow+0xf/0x20
> [ 14.821281] ? get_cpu_idle_time_us+0x204/0x2b0
> [ 14.821350] ? get_idle_time+0x57/0xb0
> [ 14.821405] ? show_stat+0x217/0x10c0
> [ 14.821463] ? seq_open+0x33/0xb0
> [ 14.821519] ? __d_alloc+0x149/0x2c0
> [ 14.821574] ? get_iowait_time+0xb0/0xb0
> [ 14.821628] ? single_open+0x4d/0xb0
> [ 14.821685] ? single_open_size+0x37/0xc0
> [ 14.821748] ? path_openat+0x7d5/0x1bd0
> [ 14.821804] ? seq_read+0xca/0x6f0
> [ 14.821872] ? _copy_to_user+0x5e/0x90
> [ 14.821937] ? cp_new_stat64+0x108/0x130
> [ 14.821991] ? __seq_open_private+0x80/0x80
> [ 14.822062] ? proc_reg_read+0x7c/0x120
> [ 14.822117] ? proc_reg_write+0x120/0x120
> [ 14.822172] ? __vfs_read+0x3e/0x240
> [ 14.822228] ? vfs_read+0x92/0x1b0
> [ 14.822282] ? SyS_read+0x45/0xa0
> [ 14.822338] ? do_fast_syscall_32+0xb9/0x220
> [ 14.822395] ? entry_SYSENTER_32+0x47/0x71
> [ 14.822447]
> ================================================================================
>
>
> --
> Meelis Roos (mr...@linux.ee)
>
