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time: Move ktime_t overflow checking into timespec_valid_strict

Andreas Bombe reported that the added ktime_t overflow checking added to
timespec_valid in commit 4e8b14526ca7 ("time: Improve sanity checking of
timekeeping inputs") was causing problems with X.org because it caused
timeouts larger then KTIME_T to be invalid.

Previously, these large timeouts would be clamped to KTIME_MAX and would
never expire, which is valid.

This patch splits the ktime_t overflow checking into a new
timespec_valid_strict function, and converts the timekeeping codes
internal checking to use this more strict function.

Reported-and-tested-by: Andreas Bombe <aeb@debian.org>
Cc: Zhouping Liu <zliu@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

authored by

John Stultz and committed by
Linus Torvalds cee58483 7a611e69

+12 -5
+7
include/linux/time.h
··· 125 125 /* Can't have more nanoseconds then a second */ 126 126 if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC) 127 127 return false; 128 + return true; 129 + } 130 + 131 + static inline bool timespec_valid_strict(const struct timespec *ts) 132 + { 133 + if (!timespec_valid(ts)) 134 + return false; 128 135 /* Disallow values that could overflow ktime_t */ 129 136 if ((unsigned long long)ts->tv_sec >= KTIME_SEC_MAX) 130 137 return false;
+5 -5
kernel/time/timekeeping.c
··· 428 428 struct timespec ts_delta, xt; 429 429 unsigned long flags; 430 430 431 - if (!timespec_valid(tv)) 431 + if (!timespec_valid_strict(tv)) 432 432 return -EINVAL; 433 433 434 434 write_seqlock_irqsave(&tk->lock, flags); ··· 476 476 477 477 /* Make sure the proposed value is valid */ 478 478 tmp = timespec_add(tk_xtime(tk), *ts); 479 - if (!timespec_valid(&tmp)) { 479 + if (!timespec_valid_strict(&tmp)) { 480 480 ret = -EINVAL; 481 481 goto error; 482 482 } ··· 659 659 struct timespec now, boot, tmp; 660 660 661 661 read_persistent_clock(&now); 662 - if (!timespec_valid(&now)) { 662 + if (!timespec_valid_strict(&now)) { 663 663 pr_warn("WARNING: Persistent clock returned invalid value!\n" 664 664 " Check your CMOS/BIOS settings.\n"); 665 665 now.tv_sec = 0; ··· 667 667 } 668 668 669 669 read_boot_clock(&boot); 670 - if (!timespec_valid(&boot)) { 670 + if (!timespec_valid_strict(&boot)) { 671 671 pr_warn("WARNING: Boot clock returned invalid value!\n" 672 672 " Check your CMOS/BIOS settings.\n"); 673 673 boot.tv_sec = 0; ··· 713 713 static void __timekeeping_inject_sleeptime(struct timekeeper *tk, 714 714 struct timespec *delta) 715 715 { 716 - if (!timespec_valid(delta)) { 716 + if (!timespec_valid_strict(delta)) { 717 717 printk(KERN_WARNING "__timekeeping_inject_sleeptime: Invalid " 718 718 "sleep delta value!\n"); 719 719 return;