linux/include
Vegard Nossum 08b1cf4964 time: Avoid undefined behaviour in ktime_add_safe()
commit 979515c564 upstream.

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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-31 12:06:08 +01:00
..
acpi Merge branch 'acpi-pci' 2015-11-07 01:30:10 +01:00
asm-generic EXPORT_SYMBOL() for asm 2018-01-23 19:50:12 +01:00
clocksource
crypto crypto: mcryptd - protect the per-CPU queue with a lock 2018-01-02 20:33:19 +01:00
drm drm: extra printk() wrapper macros 2017-12-16 10:33:49 +01:00
dt-bindings ARM: dts: Fix omap3 off mode pull defines 2017-11-21 09:21:19 +01:00
keys KEYS: Merge the type-specific data with the payload data 2015-10-21 15:18:36 +01:00
kvm KVM: arm/arm64: arch_timer: Preserve physical dist. active state on LR.active 2015-11-24 18:07:40 +01:00
linux time: Avoid undefined behaviour in ktime_add_safe() 2018-01-31 12:06:08 +01:00
math-emu
media videobuf2-core: Check user space planes array in dqbuf 2016-05-04 14:48:50 -07:00
memory
misc
net ipv4: igmp: guard against silly MTU values 2018-01-02 20:33:24 +01:00
pcmcia
ras
rdma RDMA/core: Fix incorrect structure packing for booleans 2017-03-12 06:37:29 +01:00
rxrpc
scsi scsi: sg: disable SET_FORCE_LOW_DMA 2018-01-23 19:50:14 +01:00
soc ARM: at91: define LPDDR types 2017-03-12 06:37:24 +01:00
sound ALSA: seq: Avoid invalid lockdep class warning 2017-11-15 17:13:12 +01:00
target target: Avoid early CMD_T_PRE_EXECUTE failures during ABORT_TASK 2018-01-17 09:35:31 +01:00
trace KVM: Fix stack-out-of-bounds read in write_mmio 2018-01-17 09:35:24 +01:00
uapi USB: core: Add type-specific length check of BOS descriptors 2017-12-09 18:42:44 +01:00
video drm/imx: Match imx-ipuv3-crtc components using device node in platform data 2016-06-07 18:14:37 -07:00
xen fix xen_swiotlb_dma_mmap prototype 2017-10-05 09:41:48 +02:00
Kbuild