UBSAN message from my kernel log: ================================================================================ kernel: UBSAN: Undefined behaviour in ./arch/x86/include/asm/bitops.h:328:8 kernel: load of misaligned address 00000000c503b3c8 for type 'volatile const long unsigned int' kernel: which requires 8 byte alignment kernel: CPU: 0 PID: 7415 Comm: swapon Tainted: P O T 4.19.8-gentoo #1 kernel: Hardware name: ASUSTeK COMPUTER INC. G752VY/G752VY, BIOS G752VY.304 06/29/2017 kernel: Call Trace: kernel: dump_stack+0xa1/0x11b kernel: ubsan_epilogue+0x9/0x40 kernel: ubsan_type_mismatch_common+0x17b/0x190 kernel: __ubsan_handle_type_mismatch+0x43/0x60 kernel: max_swapfile_size+0x7d/0x83 kernel: __do_sys_swapon+0x926/0x2fd0 kernel: ? task_work_run+0x7e/0x140 kernel: do_syscall_64+0x85/0x280 kernel: entry_SYSCALL_64_after_hwframe+0x49/0xbe kernel: RIP: 0033:0x7f86841d3617 kernel: Code: 73 01 c3 48 8b 0d 79 68 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 a7 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 49 68 2c 00 f7 d8 64 89 01 48 kernel: RSP: 002b:00007ffd93dc2288 EFLAGS: 00000246 ORIG_RAX: 00000000000000a7 kernel: RAX: ffffffffffffffda RBX: 000000000001bfff RCX: 00007f86841d3617 kernel: RDX: 000000000001bfff RSI: 000000000001bfff RDI: 0000557bbb60c5c0 kernel: RBP: 0000557bbb60c5c0 R08: 0000000600000000 R09: 0000000600000000 kernel: R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000003 kernel: R13: 00007ffd93dc2490 R14: 00007ffd93dc24cc R15: 0000557bbb60d5d0 kernel: ================================================================================ Info on the system: Portage 2.3.51 (python 3.6.5-final-0, hardened/linux/amd64, gcc-7.3.0, glibc-2.27-r6, 4.19.8-gentoo x86_64) ================================================================= System uname: Linux-4.19.8-gentoo-x86_64-Intel-R-_Core-TM-_i7-6700HQ_CPU_@_2.60GHz-with-gentoo-2.6 KiB Mem: 40976340 total, 16220132 free KiB Swap: 0 total, 0 free Timestamp of repository gentoo: Thu, 13 Dec 2018 12:15:01 +0000 Head commit of repository gentoo: 057645ffcdb86bd24e7c965f6e1aa03db33abb4c sh bash 4.4_p12 ld GNU ld (Gentoo 2.30 p5) 2.30.0 app-shells/bash: 4.4_p12::gentoo dev-java/java-config: 2.2.0-r4::gentoo dev-lang/perl: 5.26.2::gentoo dev-lang/python: 2.7.15::gentoo, 3.4.8::gentoo, 3.5.5::gentoo, 3.6.5::gentoo dev-util/cmake: 3.12.3::gentoo dev-util/pkgconfig: 0.29.2::gentoo sys-apps/baselayout: 2.6-r1::gentoo sys-apps/openrc: 0.38.3-r1::gentoo sys-apps/sandbox: 2.13::gentoo sys-devel/autoconf: 2.13::gentoo, 2.69-r4::gentoo sys-devel/automake: 1.11.6-r3::gentoo, 1.12.6::gentoo, 1.13.4-r2::gentoo, 1.14.1::gentoo, 1.15.1-r2::gentoo sys-devel/binutils: 2.30-r4::gentoo sys-devel/gcc: 7.3.0-r3::gentoo sys-devel/gcc-config: 1.8-r1::gentoo sys-devel/libtool: 2.4.6-r3::gentoo sys-devel/make: 4.2.1-r4::gentoo sys-kernel/linux-headers: 4.13::gentoo (virtual/os-headers) sys-libs/glibc: 2.27-r6::gentoo
Detection of undefined behavior via the UndefinedBehaviorSanitizer can be reported upstream at https://bugzilla.kernel.org
