From: Peter Zijlstra <peterz@infradead.org>
To: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Michal Marek <mmarek@suse.cz>,
Sasha Levin <sasha.levin@oracle.com>,
x86@kernel.org, linux-kbuild@vger.kernel.org,
linux-kernel@vger.kernel.org, "Theodore Ts'o" <tytso@mit.edu>,
Andreas Dilger <adilger.kernel@dilger.ca>,
Dmitry Vyukov <dvyukov@google.com>,
Konstantin Khlebnikov <koct9i@gmail.com>
Subject: Re: kernel: clockevents: shift out-of-bounds
Date: Fri, 24 Oct 2014 12:25:39 +0200 [thread overview]
Message-ID: <20141024102539.GG12706@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <5444ED06.6030008@samsung.com>
On Mon, Oct 20, 2014 at 03:07:50PM +0400, Andrey Ryabinin wrote:
>
> 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)))
Probably so indeed, clocks_calc_mult_shift() has max return value of 32,
which will indeed trigger that overflow.
next prev parent reply other threads:[~2014-10-24 10:25 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-20 10:54 [RFC] UBSan: run-time undefined behavior sanity checker Andrey Ryabinin
2014-10-20 10:54 ` [RFC PATCH] " Andrey Ryabinin
2014-10-20 19:35 ` Sasha Levin
2014-10-21 8:03 ` Andrey Ryabinin
2014-10-24 8:31 ` y.gribov
2014-10-24 10:36 ` Andrey Ryabinin
2014-10-21 9:47 ` Peter Zijlstra
2014-10-21 10:09 ` Andrey Ryabinin
2014-10-24 10:30 ` Peter Zijlstra
2014-10-21 17:06 ` Randy Dunlap
2014-10-22 9:58 ` Rasmus Villemoes
2014-10-22 11:16 ` Andrey Ryabinin
2014-10-20 11:03 ` drivers: random: Shift out-of-bounds in _mix_pool_bytes Andrey Ryabinin
2014-10-20 12:49 ` Theodore Ts'o
2014-10-20 13:58 ` Andrey Ryabinin
2014-10-20 14:08 ` Theodore Ts'o
2014-10-20 14:09 ` Daniel Borkmann
2014-10-20 14:13 ` Sasha Levin
2014-10-20 14:16 ` Theodore Ts'o
2014-10-20 14:42 ` Andrey Ryabinin
2014-10-24 10:01 ` Peter Zijlstra
2014-10-24 10:16 ` Andrey Ryabinin
2014-10-24 13:23 ` Sasha Levin
2014-10-24 13:42 ` Peter Zijlstra
2014-10-24 15:04 ` Sasha Levin
2014-10-24 15:10 ` Dmitry Vyukov
2014-10-24 21:05 ` One Thousand Gnomes
2014-10-24 22:23 ` H. Peter Anvin
2014-10-24 22:09 ` Andreas Dilger
2014-10-24 22:22 ` H. Peter Anvin
2014-10-25 0:50 ` Sasha Levin
2014-10-25 20:30 ` One Thousand Gnomes
2014-10-25 20:49 ` Andrey Ryabinin
2014-10-20 11:07 ` kernel: clockevents: shift out-of-bounds Andrey Ryabinin
2014-10-24 10:25 ` Peter Zijlstra [this message]
2014-10-20 11:16 ` fs: ext4: mballoc: negative shift exponent Andrey Ryabinin
2014-10-20 11:23 ` jbd2: revoke: negative shift exponent in hash() Andrey Ryabinin
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