![Vegard Nossum](/assets/img/avatar_default.png)
I ran into this: ================================================================================ UBSAN: Undefined behaviour in kernel/time/hrtimer.c:310:16 signed integer overflow: 9223372036854775807 + 50000 cannot be represented in type 'long long int' CPU: 2 PID: 4798 Comm: trinity-c2 Not tainted 4.8.0-rc1+ #91 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014 0000000000000000 ffff88010ce6fb88 ffffffff82344740 0000000041b58ab3 ffffffff84f97a20 ffffffff82344694 ffff88010ce6fbb0 ffff88010ce6fb60 000000000000c350 ffff88010ce6f968 dffffc0000000000 ffffffff857bc320 Call Trace: [<ffffffff82344740>] dump_stack+0xac/0xfc [<ffffffff82344694>] ? _atomic_dec_and_lock+0xc4/0xc4 [<ffffffff8242df78>] ubsan_epilogue+0xd/0x8a [<ffffffff8242e6b4>] handle_overflow+0x202/0x23d [<ffffffff8242e4b2>] ? val_to_string.constprop.6+0x11e/0x11e [<ffffffff8236df71>] ? timerqueue_add+0x151/0x410 [<ffffffff81485c48>] ? hrtimer_start_range_ns+0x3b8/0x1380 [<ffffffff81795631>] ? memset+0x31/0x40 [<ffffffff8242e6fd>] __ubsan_handle_add_overflow+0xe/0x10 [<ffffffff81488ac9>] hrtimer_nanosleep+0x5d9/0x790 [<ffffffff814884f0>] ? hrtimer_init_sleeper+0x80/0x80 [<ffffffff813a9ffb>] ? __might_sleep+0x5b/0x260 [<ffffffff8148be10>] common_nsleep+0x20/0x30 [<ffffffff814906c7>] SyS_clock_nanosleep+0x197/0x210 [<ffffffff81490530>] ? SyS_clock_getres+0x150/0x150 [<ffffffff823c7113>] ? __this_cpu_preempt_check+0x13/0x20 [<ffffffff8162ef60>] ? __context_tracking_exit.part.3+0x30/0x1b0 [<ffffffff81490530>] ? SyS_clock_getres+0x150/0x150 [<ffffffff81007bd3>] do_syscall_64+0x1b3/0x4b0 [<ffffffff845f85aa>] entry_SYSCALL64_slow_path+0x25/0x25 ================================================================================ Add a new ktime_add_unsafe() helper which doesn't check for overflow, but doesn't throw a UBSAN warning when it does overflow either. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
307 lines
7.6 KiB
C
307 lines
7.6 KiB
C
/*
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* include/linux/ktime.h
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*
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* ktime_t - nanosecond-resolution time format.
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*
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* Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
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* Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
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*
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* data type definitions, declarations, prototypes and macros.
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*
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* Started by: Thomas Gleixner and Ingo Molnar
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*
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* Credits:
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*
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* Roman Zippel provided the ideas and primary code snippets of
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* the ktime_t union and further simplifications of the original
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* code.
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*
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* For licencing details see kernel-base/COPYING
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*/
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#ifndef _LINUX_KTIME_H
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#define _LINUX_KTIME_H
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#include <linux/time.h>
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#include <linux/jiffies.h>
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/*
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* ktime_t:
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*
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* A single 64-bit variable is used to store the hrtimers
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* internal representation of time values in scalar nanoseconds. The
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* design plays out best on 64-bit CPUs, where most conversions are
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* NOPs and most arithmetic ktime_t operations are plain arithmetic
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* operations.
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*
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*/
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union ktime {
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s64 tv64;
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};
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typedef union ktime ktime_t; /* Kill this */
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/**
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* ktime_set - Set a ktime_t variable from a seconds/nanoseconds value
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* @secs: seconds to set
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* @nsecs: nanoseconds to set
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*
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* Return: The ktime_t representation of the value.
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*/
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static inline ktime_t ktime_set(const s64 secs, const unsigned long nsecs)
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{
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if (unlikely(secs >= KTIME_SEC_MAX))
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return (ktime_t){ .tv64 = KTIME_MAX };
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return (ktime_t) { .tv64 = secs * NSEC_PER_SEC + (s64)nsecs };
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}
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/* Subtract two ktime_t variables. rem = lhs -rhs: */
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#define ktime_sub(lhs, rhs) \
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({ (ktime_t){ .tv64 = (lhs).tv64 - (rhs).tv64 }; })
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/* Add two ktime_t variables. res = lhs + rhs: */
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#define ktime_add(lhs, rhs) \
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({ (ktime_t){ .tv64 = (lhs).tv64 + (rhs).tv64 }; })
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/*
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* Same as ktime_add(), but avoids undefined behaviour on overflow; however,
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* this means that you must check the result for overflow yourself.
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*/
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#define ktime_add_unsafe(lhs, rhs) \
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({ (ktime_t){ .tv64 = (u64) (lhs).tv64 + (rhs).tv64 }; })
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/*
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* Add a ktime_t variable and a scalar nanosecond value.
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* res = kt + nsval:
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*/
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#define ktime_add_ns(kt, nsval) \
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({ (ktime_t){ .tv64 = (kt).tv64 + (nsval) }; })
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/*
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* Subtract a scalar nanosecod from a ktime_t variable
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* res = kt - nsval:
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*/
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#define ktime_sub_ns(kt, nsval) \
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({ (ktime_t){ .tv64 = (kt).tv64 - (nsval) }; })
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/* convert a timespec to ktime_t format: */
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static inline ktime_t timespec_to_ktime(struct timespec ts)
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{
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return ktime_set(ts.tv_sec, ts.tv_nsec);
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}
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/* convert a timespec64 to ktime_t format: */
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static inline ktime_t timespec64_to_ktime(struct timespec64 ts)
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{
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return ktime_set(ts.tv_sec, ts.tv_nsec);
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}
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/* convert a timeval to ktime_t format: */
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static inline ktime_t timeval_to_ktime(struct timeval tv)
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{
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return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC);
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}
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/* Map the ktime_t to timespec conversion to ns_to_timespec function */
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#define ktime_to_timespec(kt) ns_to_timespec((kt).tv64)
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/* Map the ktime_t to timespec conversion to ns_to_timespec function */
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#define ktime_to_timespec64(kt) ns_to_timespec64((kt).tv64)
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/* Map the ktime_t to timeval conversion to ns_to_timeval function */
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#define ktime_to_timeval(kt) ns_to_timeval((kt).tv64)
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/* Convert ktime_t to nanoseconds - NOP in the scalar storage format: */
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#define ktime_to_ns(kt) ((kt).tv64)
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/**
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* ktime_equal - Compares two ktime_t variables to see if they are equal
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* @cmp1: comparable1
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* @cmp2: comparable2
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*
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* Compare two ktime_t variables.
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*
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* Return: 1 if equal.
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*/
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static inline int ktime_equal(const ktime_t cmp1, const ktime_t cmp2)
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{
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return cmp1.tv64 == cmp2.tv64;
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}
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/**
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* ktime_compare - Compares two ktime_t variables for less, greater or equal
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* @cmp1: comparable1
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* @cmp2: comparable2
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*
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* Return: ...
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* cmp1 < cmp2: return <0
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* cmp1 == cmp2: return 0
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* cmp1 > cmp2: return >0
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*/
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static inline int ktime_compare(const ktime_t cmp1, const ktime_t cmp2)
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{
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if (cmp1.tv64 < cmp2.tv64)
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return -1;
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if (cmp1.tv64 > cmp2.tv64)
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return 1;
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return 0;
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}
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/**
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* ktime_after - Compare if a ktime_t value is bigger than another one.
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* @cmp1: comparable1
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* @cmp2: comparable2
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*
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* Return: true if cmp1 happened after cmp2.
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*/
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static inline bool ktime_after(const ktime_t cmp1, const ktime_t cmp2)
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{
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return ktime_compare(cmp1, cmp2) > 0;
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}
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/**
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* ktime_before - Compare if a ktime_t value is smaller than another one.
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* @cmp1: comparable1
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* @cmp2: comparable2
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*
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* Return: true if cmp1 happened before cmp2.
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*/
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static inline bool ktime_before(const ktime_t cmp1, const ktime_t cmp2)
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{
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return ktime_compare(cmp1, cmp2) < 0;
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}
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#if BITS_PER_LONG < 64
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extern s64 __ktime_divns(const ktime_t kt, s64 div);
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static inline s64 ktime_divns(const ktime_t kt, s64 div)
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{
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/*
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* Negative divisors could cause an inf loop,
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* so bug out here.
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*/
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BUG_ON(div < 0);
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if (__builtin_constant_p(div) && !(div >> 32)) {
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s64 ns = kt.tv64;
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u64 tmp = ns < 0 ? -ns : ns;
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do_div(tmp, div);
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return ns < 0 ? -tmp : tmp;
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} else {
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return __ktime_divns(kt, div);
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}
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}
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#else /* BITS_PER_LONG < 64 */
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static inline s64 ktime_divns(const ktime_t kt, s64 div)
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{
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/*
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* 32-bit implementation cannot handle negative divisors,
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* so catch them on 64bit as well.
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*/
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WARN_ON(div < 0);
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return kt.tv64 / div;
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}
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#endif
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static inline s64 ktime_to_us(const ktime_t kt)
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{
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return ktime_divns(kt, NSEC_PER_USEC);
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}
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static inline s64 ktime_to_ms(const ktime_t kt)
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{
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return ktime_divns(kt, NSEC_PER_MSEC);
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}
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static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier)
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{
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return ktime_to_us(ktime_sub(later, earlier));
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}
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static inline s64 ktime_ms_delta(const ktime_t later, const ktime_t earlier)
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{
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return ktime_to_ms(ktime_sub(later, earlier));
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}
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static inline ktime_t ktime_add_us(const ktime_t kt, const u64 usec)
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{
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return ktime_add_ns(kt, usec * NSEC_PER_USEC);
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}
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static inline ktime_t ktime_add_ms(const ktime_t kt, const u64 msec)
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{
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return ktime_add_ns(kt, msec * NSEC_PER_MSEC);
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}
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static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec)
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{
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return ktime_sub_ns(kt, usec * NSEC_PER_USEC);
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}
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extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs);
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/**
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* ktime_to_timespec_cond - convert a ktime_t variable to timespec
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* format only if the variable contains data
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* @kt: the ktime_t variable to convert
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* @ts: the timespec variable to store the result in
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*
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* Return: %true if there was a successful conversion, %false if kt was 0.
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*/
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static inline __must_check bool ktime_to_timespec_cond(const ktime_t kt,
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struct timespec *ts)
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{
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if (kt.tv64) {
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*ts = ktime_to_timespec(kt);
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return true;
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} else {
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return false;
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}
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}
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/**
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* ktime_to_timespec64_cond - convert a ktime_t variable to timespec64
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* format only if the variable contains data
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* @kt: the ktime_t variable to convert
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* @ts: the timespec variable to store the result in
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*
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* Return: %true if there was a successful conversion, %false if kt was 0.
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*/
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static inline __must_check bool ktime_to_timespec64_cond(const ktime_t kt,
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struct timespec64 *ts)
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{
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if (kt.tv64) {
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*ts = ktime_to_timespec64(kt);
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return true;
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} else {
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return false;
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}
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}
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/*
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* The resolution of the clocks. The resolution value is returned in
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* the clock_getres() system call to give application programmers an
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* idea of the (in)accuracy of timers. Timer values are rounded up to
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* this resolution values.
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*/
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#define LOW_RES_NSEC TICK_NSEC
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#define KTIME_LOW_RES (ktime_t){ .tv64 = LOW_RES_NSEC }
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static inline ktime_t ns_to_ktime(u64 ns)
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{
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static const ktime_t ktime_zero = { .tv64 = 0 };
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return ktime_add_ns(ktime_zero, ns);
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}
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static inline ktime_t ms_to_ktime(u64 ms)
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{
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static const ktime_t ktime_zero = { .tv64 = 0 };
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return ktime_add_ms(ktime_zero, ms);
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}
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# include <linux/timekeeping.h>
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#endif
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