Messages in this thread | | | Date | Mon, 20 Oct 2014 15:07:50 +0400 | From | Andrey Ryabinin <> | Subject | kernel: clockevents: shift out-of-bounds |
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On kernel with UBSan enabled I've got following:
UBSan: Undefined behaviour in ../kernel/time/clockevents.c:75:34 shift exponent 32 is to large for 32-bit type 'unsigned int' CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.17.0-rc7+ #39 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 0000000000000000 0000000000000000 0000000000000001 ffffffff83003db0 ffffffff82a30940 0000000000000020 ffffffff83003dc0 ffffffff819502e9 ffffffff83003e40 ffffffff81950735 ffff88013f003233 0000000000000000 Call Trace: dump_stack (/home/andrew/linux/lib/dump_stack.c:52) ubsan_epilogue (/home/andrew/linux/lib/ubsan.c:122) __ubsan_handle_shift_out_of_bounds (/home/andrew/linux/lib/ubsan.c:390) ? hpet_enable (/home/andrew/linux/arch/x86/kernel/hpet.c:862) cev_delta2ns (/home/andrew/linux/kernel/time/clockevents.c:75 (discriminator 1)) clockevents_config.part.2 (/home/andrew/linux/kernel/time/clockevents.c:421) ? __clocksource_select (/home/andrew/linux/kernel/time/clocksource.c:607 /home/andrew/linux/kernel/time/clocksource.c:631) clockevents_config_and_register (/home/andrew/linux/kernel/time/clockevents.c:440) hpet_enable (/home/andrew/linux/arch/x86/kernel/hpet.c:305 /home/andrew/linux/arch/x86/kernel/hpet.c:891) hpet_time_init (/home/andrew/linux/arch/x86/kernel/time.c:79) x86_late_time_init (/home/andrew/linux/arch/x86/kernel/time.c:87) start_kernel (/home/andrew/linux/init/main.c:637) ? early_idt_handlers (/home/andrew/linux/arch/x86/kernel/head_64.S:344) x86_64_start_reservations (/home/andrew/linux/arch/x86/kernel/head64.c:194) x86_64_start_kernel (/home/andrew/linux/arch/x86/kernel/head64.c:183)
I guess it should be 1ULL here instead of 1U: (!ismax || evt->mult <= (1U << evt->shift)))
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