From 53c035204253efe373d9ff166fae6147e8c693b6 Mon Sep 17 00:00:00 2001 From: Baruch Siach Date: Wed, 17 Jul 2013 12:46:53 +0300 Subject: sched_clock: Fix integer overflow The expression '(1 << 32)' happens to evaluate as 0 on ARM, but it evaluates as 1 on xtensa and x86_64. This zeros sched_clock_mask, and breaks sched_clock(). Set the type of 1 to 'unsigned long long' to get the value we need. Reported-by: Max Filippov Tested-by: Max Filippov Acked-by: Russell King Signed-off-by: Baruch Siach Signed-off-by: John Stultz --- kernel/time/sched_clock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/time') diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c index a326f27d7f0..0b479a6a22b 100644 --- a/kernel/time/sched_clock.c +++ b/kernel/time/sched_clock.c @@ -121,7 +121,7 @@ void __init setup_sched_clock(u32 (*read)(void), int bits, unsigned long rate) BUG_ON(bits > 32); WARN_ON(!irqs_disabled()); read_sched_clock = read; - sched_clock_mask = (1 << bits) - 1; + sched_clock_mask = (1ULL << bits) - 1; cd.rate = rate; /* calculate the mult/shift to convert counter ticks to ns. */ -- cgit v1.2.3-70-g09d2 From 543487c7a2670bb0d96c00673a44b74360e3b6c1 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 16 Jul 2013 10:22:12 -0400 Subject: nohz: Do not warn about unstable tsc unless user uses nohz_full If the user enables CONFIG_NO_HZ_FULL and runs the kernel on a machine with an unstable TSC, it will produce a WARN_ON dump as well as taint the kernel. This is a bit extreme for a kernel that just enables a feature but doesn't use it. The warning should only happen if the user tries to use the feature by either adding nohz_full to the kernel command line, or by enabling CONFIG_NO_HZ_FULL_ALL that makes nohz used on all CPUs at boot up. Note, this second feature should not (yet) be used by distros or anyone that doesn't care if NO_HZ is used or not. Signed-off-by: Steven Rostedt Cc: Paul E. McKenney Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Borislav Petkov Cc: Li Zhong Cc: Mike Galbraith Cc: Kevin Hilman Signed-off-by: Frederic Weisbecker --- kernel/time/tick-sched.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel/time') diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index e80183f4a6c..1102534a1a5 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -182,7 +182,8 @@ static bool can_stop_full_tick(void) * Don't allow the user to think they can get * full NO_HZ with this machine. */ - WARN_ONCE(1, "NO_HZ FULL will not work with unstable sched clock"); + WARN_ONCE(have_nohz_full_mask, + "NO_HZ FULL will not work with unstable sched clock"); return false; } #endif -- cgit v1.2.3-70-g09d2 From ca06416b2b4fa562cd3c3f9eb4198c3b2a983342 Mon Sep 17 00:00:00 2001 From: Li Zhong Date: Tue, 16 Jul 2013 12:18:47 +0800 Subject: nohz: fix compile warning in tick_nohz_init() cpu is not used after commit 5b8621a68fdcd2baf1d3b413726f913a5254d46a Signed-off-by: Li Zhong Cc: Steven Rostedt Cc: Paul E. McKenney Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Borislav Petkov Cc: Li Zhong Cc: Mike Galbraith Cc: Kevin Hilman Signed-off-by: Frederic Weisbecker --- kernel/time/tick-sched.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'kernel/time') diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 1102534a1a5..9563c744dad 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -344,8 +344,6 @@ static int tick_nohz_init_all(void) void __init tick_nohz_init(void) { - int cpu; - if (!have_nohz_full_mask) { if (tick_nohz_init_all() < 0) return; -- cgit v1.2.3-70-g09d2 From 84a78a6504f5c5394a8e558702e5b54131f01d14 Mon Sep 17 00:00:00 2001 From: Nathan Zimmer Date: Wed, 28 Aug 2013 16:35:14 -0700 Subject: timer_list: correct the iterator for timer_list Correct an issue with /proc/timer_list reported by Holger. When reading from the proc file with a sufficiently small buffer, 2k so not really that small, there was one could get hung trying to read the file a chunk at a time. The timer_list_start function failed to account for the possibility that the offset was adjusted outside the timer_list_next. Signed-off-by: Nathan Zimmer Reported-by: Holger Hans Peter Freyther Cc: John Stultz Cc: Thomas Gleixner Cc: Berke Durak Cc: Jeff Layton Tested-by: Al Viro Cc: # 3.10.x Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/time/timer_list.c | 41 ++++++++++++++++++++++++----------------- 1 file changed, 24 insertions(+), 17 deletions(-) (limited to 'kernel/time') diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c index 3bdf2832301..61ed862cdd3 100644 --- a/kernel/time/timer_list.c +++ b/kernel/time/timer_list.c @@ -265,10 +265,9 @@ static inline void timer_list_header(struct seq_file *m, u64 now) static int timer_list_show(struct seq_file *m, void *v) { struct timer_list_iter *iter = v; - u64 now = ktime_to_ns(ktime_get()); if (iter->cpu == -1 && !iter->second_pass) - timer_list_header(m, now); + timer_list_header(m, iter->now); else if (!iter->second_pass) print_cpu(m, iter->cpu, iter->now); #ifdef CONFIG_GENERIC_CLOCKEVENTS @@ -298,33 +297,41 @@ void sysrq_timer_list_show(void) return; } -static void *timer_list_start(struct seq_file *file, loff_t *offset) +static void *move_iter(struct timer_list_iter *iter, loff_t offset) { - struct timer_list_iter *iter = file->private; - - if (!*offset) { - iter->cpu = -1; - iter->now = ktime_to_ns(ktime_get()); - } else if (iter->cpu >= nr_cpu_ids) { + for (; offset; offset--) { + iter->cpu = cpumask_next(iter->cpu, cpu_online_mask); + if (iter->cpu >= nr_cpu_ids) { #ifdef CONFIG_GENERIC_CLOCKEVENTS - if (!iter->second_pass) { - iter->cpu = -1; - iter->second_pass = true; - } else - return NULL; + if (!iter->second_pass) { + iter->cpu = -1; + iter->second_pass = true; + } else + return NULL; #else - return NULL; + return NULL; #endif + } } return iter; } +static void *timer_list_start(struct seq_file *file, loff_t *offset) +{ + struct timer_list_iter *iter = file->private; + + if (!*offset) + iter->now = ktime_to_ns(ktime_get()); + iter->cpu = -1; + iter->second_pass = false; + return move_iter(iter, *offset); +} + static void *timer_list_next(struct seq_file *file, void *v, loff_t *offset) { struct timer_list_iter *iter = file->private; - iter->cpu = cpumask_next(iter->cpu, cpu_online_mask); ++*offset; - return timer_list_start(file, offset); + return move_iter(iter, 1); } static void timer_list_stop(struct seq_file *seq, void *v) -- cgit v1.2.3-70-g09d2