From 0696b711e4be45fa104c12329f617beb29c03f78 Mon Sep 17 00:00:00 2001 From: Lin Ming Date: Tue, 17 Nov 2009 13:49:50 +0800 Subject: timekeeping: Fix clock_gettime vsyscall time warp Since commit 0a544198 "timekeeping: Move NTP adjusted clock multiplier to struct timekeeper" the clock multiplier of vsyscall is updated with the unmodified clock multiplier of the clock source and not with the NTP adjusted multiplier of the timekeeper. This causes user space observerable time warps: new CLOCK-warp maximum: 120 nsecs, 00000025c337c537 -> 00000025c337c4bf Add a new argument "mult" to update_vsyscall() and hand in the timekeeping internal NTP adjusted multiplier. Signed-off-by: Lin Ming Cc: "Zhang Yanmin" Cc: Martin Schwidefsky Cc: Benjamin Herrenschmidt Cc: Tony Luck LKML-Reference: <1258436990.17765.83.camel@minggr.sh.intel.com> Signed-off-by: Thomas Gleixner --- arch/ia64/kernel/time.c | 4 ++-- arch/powerpc/kernel/time.c | 5 +++-- arch/s390/kernel/time.c | 3 ++- arch/x86/kernel/vsyscall_64.c | 5 +++-- include/linux/clocksource.h | 6 ++++-- kernel/time/timekeeping.c | 6 +++--- 6 files changed, 17 insertions(+), 12 deletions(-) diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c index 4990495d753..a35c661e5e8 100644 --- a/arch/ia64/kernel/time.c +++ b/arch/ia64/kernel/time.c @@ -473,7 +473,7 @@ void update_vsyscall_tz(void) { } -void update_vsyscall(struct timespec *wall, struct clocksource *c) +void update_vsyscall(struct timespec *wall, struct clocksource *c, u32 mult) { unsigned long flags; @@ -481,7 +481,7 @@ void update_vsyscall(struct timespec *wall, struct clocksource *c) /* copy fsyscall clock data */ fsyscall_gtod_data.clk_mask = c->mask; - fsyscall_gtod_data.clk_mult = c->mult; + fsyscall_gtod_data.clk_mult = mult; fsyscall_gtod_data.clk_shift = c->shift; fsyscall_gtod_data.clk_fsys_mmio = c->fsys_mmio; fsyscall_gtod_data.clk_cycle_last = c->cycle_last; diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index a136a11c490..39713312fbc 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -828,7 +828,8 @@ static cycle_t timebase_read(struct clocksource *cs) return (cycle_t)get_tb(); } -void update_vsyscall(struct timespec *wall_time, struct clocksource *clock) +void update_vsyscall(struct timespec *wall_time, struct clocksource *clock, + u32 mult) { u64 t2x, stamp_xsec; @@ -841,7 +842,7 @@ void update_vsyscall(struct timespec *wall_time, struct clocksource *clock) /* XXX this assumes clock->shift == 22 */ /* 4611686018 ~= 2^(20+64-22) / 1e9 */ - t2x = (u64) clock->mult * 4611686018ULL; + t2x = (u64) mult * 4611686018ULL; stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC; do_div(stamp_xsec, 1000000000); stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC; diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c index 34162a0b2ca..68e1ecf5eba 100644 --- a/arch/s390/kernel/time.c +++ b/arch/s390/kernel/time.c @@ -214,7 +214,8 @@ struct clocksource * __init clocksource_default_clock(void) return &clocksource_tod; } -void update_vsyscall(struct timespec *wall_time, struct clocksource *clock) +void update_vsyscall(struct timespec *wall_time, struct clocksource *clock, + u32 mult) { if (clock != &clocksource_tod) return; diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c index 8cb4974ff59..62f39d79b77 100644 --- a/arch/x86/kernel/vsyscall_64.c +++ b/arch/x86/kernel/vsyscall_64.c @@ -73,7 +73,8 @@ void update_vsyscall_tz(void) write_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags); } -void update_vsyscall(struct timespec *wall_time, struct clocksource *clock) +void update_vsyscall(struct timespec *wall_time, struct clocksource *clock, + u32 mult) { unsigned long flags; @@ -82,7 +83,7 @@ void update_vsyscall(struct timespec *wall_time, struct clocksource *clock) vsyscall_gtod_data.clock.vread = clock->vread; vsyscall_gtod_data.clock.cycle_last = clock->cycle_last; vsyscall_gtod_data.clock.mask = clock->mask; - vsyscall_gtod_data.clock.mult = clock->mult; + vsyscall_gtod_data.clock.mult = mult; vsyscall_gtod_data.clock.shift = clock->shift; vsyscall_gtod_data.wall_time_sec = wall_time->tv_sec; vsyscall_gtod_data.wall_time_nsec = wall_time->tv_nsec; diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index 83d2fbd81b9..95e4995d998 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -280,10 +280,12 @@ extern struct clocksource * __init __weak clocksource_default_clock(void); extern void clocksource_mark_unstable(struct clocksource *cs); #ifdef CONFIG_GENERIC_TIME_VSYSCALL -extern void update_vsyscall(struct timespec *ts, struct clocksource *c); +extern void +update_vsyscall(struct timespec *ts, struct clocksource *c, u32 mult); extern void update_vsyscall_tz(void); #else -static inline void update_vsyscall(struct timespec *ts, struct clocksource *c) +static inline void +update_vsyscall(struct timespec *ts, struct clocksource *c, u32 mult) { } diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index c3a4e2907ea..2a6d3e3e2c3 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -177,7 +177,7 @@ void timekeeping_leap_insert(int leapsecond) { xtime.tv_sec += leapsecond; wall_to_monotonic.tv_sec -= leapsecond; - update_vsyscall(&xtime, timekeeper.clock); + update_vsyscall(&xtime, timekeeper.clock, timekeeper.mult); } #ifdef CONFIG_GENERIC_TIME @@ -337,7 +337,7 @@ int do_settimeofday(struct timespec *tv) timekeeper.ntp_error = 0; ntp_clear(); - update_vsyscall(&xtime, timekeeper.clock); + update_vsyscall(&xtime, timekeeper.clock, timekeeper.mult); write_sequnlock_irqrestore(&xtime_lock, flags); @@ -811,7 +811,7 @@ void update_wall_time(void) update_xtime_cache(nsecs); /* check to see if there is a new clocksource to use */ - update_vsyscall(&xtime, timekeeper.clock); + update_vsyscall(&xtime, timekeeper.clock, timekeeper.mult); } /** -- cgit v1.2.3 From 8747d793fc5c4d3e4decd41d55f6dc24498dd5f5 Mon Sep 17 00:00:00 2001 From: Stanislaw Gruszka Date: Tue, 17 Nov 2009 14:14:12 -0800 Subject: itimers: Fix racy writes to cpu_itimer fields incr_error and error fields of struct cpu_itimer are used when calculating next timer tick in check_cpu_itimers() and should not be modified without tsk->sighand->siglock taken. Signed-off-by: Stanislaw Gruszka LKML-Reference: <1253802903-979-1-git-send-email-sgruszka@redhat.com> Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Oleg Nesterov Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Thomas Gleixner --- kernel/itimer.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/kernel/itimer.c b/kernel/itimer.c index b03451ede52..d802883153d 100644 --- a/kernel/itimer.c +++ b/kernel/itimer.c @@ -146,6 +146,7 @@ static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, { cputime_t cval, nval, cinterval, ninterval; s64 ns_ninterval, ns_nval; + u32 error, incr_error; struct cpu_itimer *it = &tsk->signal->it[clock_id]; nval = timeval_to_cputime(&value->it_value); @@ -153,8 +154,8 @@ static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, ninterval = timeval_to_cputime(&value->it_interval); ns_ninterval = timeval_to_ns(&value->it_interval); - it->incr_error = cputime_sub_ns(ninterval, ns_ninterval); - it->error = cputime_sub_ns(nval, ns_nval); + error = cputime_sub_ns(nval, ns_nval); + incr_error = cputime_sub_ns(ninterval, ns_ninterval); spin_lock_irq(&tsk->sighand->siglock); @@ -168,6 +169,8 @@ static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, } it->expires = nval; it->incr = ninterval; + it->error = error; + it->incr_error = incr_error; trace_itimer_state(clock_id == CPUCLOCK_VIRT ? ITIMER_VIRTUAL : ITIMER_PROF, value, nval); -- cgit v1.2.3 From 8629ea2eaba8ca0de2e38ce1b4a825e16255976e Mon Sep 17 00:00:00 2001 From: Feng Tang Date: Thu, 3 Sep 2009 16:32:53 +0800 Subject: hrtimer: Fix /proc/timer_list regression commit 507e1231 (timer stats: Optimize by adding quick check to avoid function calls) introduced a regression in /proc/timer_list. /proc/timer_list shows now #0: , tick_sched_timer, S:01, <(null)>, /-1 instead of #0: , tick_sched_timer, S:01, hrtimer_start, swapper/0 Revert the hrtimer quick check for now. The optimization needs more thought, but this is neither 2.6.32-rc7 nor stable material. [ tglx: - Removed unrelated changes from the original patch - Prevent unneccesary call to timer_stats_update_stats - massaged the changelog ] Signed-off-by: Feng Tang LKML-Reference: Cc: Heiko Carstens Cc: stable@kernel.org Signed-off-by: Andrew Morton Signed-off-by: Thomas Gleixner --- include/linux/hrtimer.h | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index ff037f0b1b4..9bace4b9f4f 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -446,7 +446,7 @@ extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf, static inline void timer_stats_account_hrtimer(struct hrtimer *timer) { - if (likely(!timer->start_site)) + if (likely(!timer_stats_active)) return; timer_stats_update_stats(timer, timer->start_pid, timer->start_site, timer->function, timer->start_comm, 0); @@ -457,8 +457,6 @@ extern void __timer_stats_hrtimer_set_start_info(struct hrtimer *timer, static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer) { - if (likely(!timer_stats_active)) - return; __timer_stats_hrtimer_set_start_info(timer, __builtin_return_address(0)); } -- cgit v1.2.3