Created attachment 220151 [details] .config [ 90.407195] ================================================================================ [ 90.407213] UBSAN: Undefined behaviour in /usr/local/src/kernel/linux-git/kernel/sched/fair.c:5066:17 [ 90.407221] signed integer overflow: [ 90.407226] -151732750385297 * 63612 cannot be represented in type 'long long int' [ 90.407236] CPU: 2 PID: 5465 Comm: panel-8-xfce4-o Tainted: G O 4.7.0-rc3-00002-g44c5afa #1 [ 90.407241] Hardware name: Apple Inc. MacBookPro8,2/Mac-94245A3940C91C80, BIOS MBP81.88Z.0047.B27.1201241646 01/24/12 [ 90.407247] ffff75fff74fff6f ffff88024bf3b8a0 ffffffff815c8665 0000000000000007 [ 90.407260] ffff88024bf3b8d0 000000000000f87c ffff88024bf3b8b8 ffffffff8163e77d [ 90.407270] ffffffff8211fda8 ffff88024bf3b948 ffffffff8163f1a8 0000002a00000046 [ 90.407280] Call Trace: [ 90.407296] [<ffffffff815c8665>] dump_stack+0x68/0xa3 [ 90.407307] [<ffffffff8163e77d>] ubsan_epilogue+0xd/0x40 [ 90.407316] [<ffffffff8163f1a8>] handle_overflow+0xc8/0x100 [ 90.407326] [<ffffffff8163f20e>] __ubsan_handle_mul_overflow+0xe/0x10 [ 90.407336] [<ffffffff81167efd>] select_task_rq_fair+0xfcd/0x1110 [ 90.407344] [<ffffffff8116704a>] ? select_task_rq_fair+0x11a/0x1110 [ 90.407355] [<ffffffff81154c5c>] try_to_wake_up+0xec/0x770 [ 90.407362] [<ffffffff81197aed>] ? __lock_acquire+0x1dd/0x20f0 [ 90.407371] [<ffffffff811553f2>] default_wake_function+0x22/0x50 [ 90.407379] [<ffffffff81369e42>] pollwake+0x82/0x100 [ 90.407387] [<ffffffff811553d0>] ? wake_up_q+0xd0/0xd0 [ 90.407394] [<ffffffff81185936>] __wake_up_common+0x66/0x120 [ 90.407401] [<ffffffff81185ab0>] __wake_up_sync_key+0x40/0x60 [ 90.407412] [<ffffffff8191e81c>] sock_def_readable+0xcc/0x3d0 [ 90.407420] [<ffffffff8191e750>] ? sock_def_error_report+0x3d0/0x3d0 [ 90.407429] [<ffffffff81a8ddc7>] unix_stream_sendmsg+0x1c7/0x510 [ 90.407437] [<ffffffff81916818>] sock_write_iter+0xb8/0x180 [ 90.407447] [<ffffffff81349e45>] do_iter_readv_writev+0xc5/0x210 [ 90.407455] [<ffffffff8134adbb>] do_readv_writev+0x12b/0x3c0 [ 90.407463] [<ffffffff8134b33e>] vfs_writev+0x4e/0x80 [ 90.407471] [<ffffffff8137e1b3>] ? __fdget_pos+0x13/0x70 [ 90.407478] [<ffffffff8134b3c0>] do_writev+0x50/0x110 [ 90.407486] [<ffffffff8134cccb>] SyS_writev+0xb/0x10 [ 90.407496] [<ffffffff81003aa6>] do_syscall_64+0x76/0x1d0 [ 90.407507] [<ffffffff81b3219e>] entry_SYSCALL64_slow_path+0x25/0x25 [ 90.407512] ================================================================================
Do you know if is something new with 4.7-rc? if yes it will qualify as regression.
I don't know if this is new, I did not have UBSAN checks enabled before 4.7-rc.
I just found the time to compile and boot Linux 4.6.2 with as close as possible a config - no UBSAN splat in kernel/sched/fair.c there. I'd count that as a regression then.
Does not appear in (at least) 4.10 anymore.