linux-kernel - [tip: timers/core] hrtimer: Use raw_cpu_ptr() in clock_was

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <162880080996.395.7066106924439766648.tip-bot2@tip-bot2>
Date:   Thu, 12 Aug 2021 20:40:09 -0000
From:   "tip-bot2 for Thomas Gleixner" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Mike Galbraith <efault@....de>,
        Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: timers/core] hrtimer: Use raw_cpu_ptr() in clock_was_set()

The following commit has been merged into the timers/core branch of tip:

Commit-ID:     9482fd71dbb8f0d1a61821a83e467dc0a9d7b429
Gitweb:        https://git.kernel.org/tip/9482fd71dbb8f0d1a61821a83e467dc0a9d7b429
Author:        Thomas Gleixner <tglx@...utronix.de>
AuthorDate:    Thu, 12 Aug 2021 22:31:24 +02:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Thu, 12 Aug 2021 22:34:40 +02:00

hrtimer: Use raw_cpu_ptr() in clock_was_set()

clock_was_set() can be invoked from preemptible context. Use raw_cpu_ptr()
to check whether high resolution mode is active or not. It does not matter
whether the task migrates after acquiring the pointer.

Fixes: e71a4153b7c2 ("hrtimer: Force clock_was_set() handling for the HIGHRES=n, NOHZ=y case")
Reported-by: Mike Galbraith <efault@....de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Link: https://lore.kernel.org/r/875ywacsmb.ffs@tglx

---
 kernel/time/hrtimer.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 88aefc3..33b00e2 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -944,10 +944,11 @@ static bool update_needs_ipi(struct hrtimer_cpu_base *cpu_base,
  */
 void clock_was_set(unsigned int bases)
 {
+	struct hrtimer_cpu_base *cpu_base = raw_cpu_ptr(&hrtimer_bases);
 	cpumask_var_t mask;
 	int cpu;
 
-	if (!hrtimer_hres_active() && !tick_nohz_active)
+	if (!__hrtimer_hres_active(cpu_base) && !tick_nohz_active)
 		goto out_timerfd;
 
 	if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) {
@@ -958,9 +959,9 @@ void clock_was_set(unsigned int bases)
 	/* Avoid interrupting CPUs if possible */
 	cpus_read_lock();
 	for_each_online_cpu(cpu) {
-		struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
 		unsigned long flags;
 
+		cpu_base = &per_cpu(hrtimer_bases, cpu);
 		raw_spin_lock_irqsave(&cpu_base->lock, flags);
 
 		if (update_needs_ipi(cpu_base, bases))