From: tip-bot for Hidetoshi Seto <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: ishii.shuuichir@jp.fujitsu.com, torvalds@linux-foundation.org,
seto.hidetoshi@jp.fujitsu.com, tglx@linutronix.de,
joe.lawrence@redhat.com, peterz@infradead.org,
tarumizu.kohei@jp.fujitsu.com, mingo@kernel.org,
m.mizuma@jp.fujitsu.com, efault@gmx.de,
linux-kernel@vger.kernel.org, msys.mizuma@gmail.com,
hpa@zytor.com
Subject: [tip:sched/core] sched/debug: Initialize sd_sysctl_cpus if !CONFIG_CPUMASK_OFFSTACK
Date: Mon, 4 Feb 2019 01:02:01 -0800 [thread overview]
Message-ID: <tip-1ca4fa3ab604734e38e2a3000c9abf788512ffa7@git.kernel.org> (raw)
In-Reply-To: <20190129151245.5073-1-msys.mizuma@gmail.com>
Commit-ID: 1ca4fa3ab604734e38e2a3000c9abf788512ffa7
Gitweb: https://git.kernel.org/tip/1ca4fa3ab604734e38e2a3000c9abf788512ffa7
Author: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
AuthorDate: Tue, 29 Jan 2019 10:12:45 -0500
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 4 Feb 2019 09:13:21 +0100
sched/debug: Initialize sd_sysctl_cpus if !CONFIG_CPUMASK_OFFSTACK
register_sched_domain_sysctl() copies the cpu_possible_mask into
sd_sysctl_cpus, but only if sd_sysctl_cpus hasn't already been
allocated (ie, CONFIG_CPUMASK_OFFSTACK is set). However, when
CONFIG_CPUMASK_OFFSTACK is not set, sd_sysctl_cpus is left
uninitialized (all zeroes) and the kernel may fail to initialize
sched_domain sysctl entries for all possible CPUs.
This is visible to the user if the kernel is booted with maxcpus=n, or
if ACPI tables have been modified to leave CPUs offline, and then
checking for missing /proc/sys/kernel/sched_domain/cpu* entries.
Fix this by separating the allocation and initialization, and adding a
flag to initialize the possible CPU entries while system booting only.
Tested-by: Syuuichirou Ishii <ishii.shuuichir@jp.fujitsu.com>
Tested-by: Tarumizu, Kohei <tarumizu.kohei@jp.fujitsu.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masayoshi Mizuma <msys.mizuma@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190129151245.5073-1-msys.mizuma@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/sched/debug.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index de3de997e245..8039d62ae36e 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -315,6 +315,7 @@ void register_sched_domain_sysctl(void)
{
static struct ctl_table *cpu_entries;
static struct ctl_table **cpu_idx;
+ static bool init_done = false;
char buf[32];
int i;
@@ -344,7 +345,10 @@ void register_sched_domain_sysctl(void)
if (!cpumask_available(sd_sysctl_cpus)) {
if (!alloc_cpumask_var(&sd_sysctl_cpus, GFP_KERNEL))
return;
+ }
+ if (!init_done) {
+ init_done = true;
/* init to possible to not have holes in @cpu_entries */
cpumask_copy(sd_sysctl_cpus, cpu_possible_mask);
}
prev parent reply other threads:[~2019-02-04 9:02 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-29 15:12 [PATCH] sched/debug: initialize sd_sysctl_cpus if !CONFIG_CPUMASK_OFFSTACK Masayoshi Mizuma
2019-01-29 16:16 ` Joe Lawrence
2019-01-30 20:14 ` Peter Zijlstra
2019-01-31 13:44 ` Masayoshi Mizuma
2019-02-01 22:33 ` Joe Lawrence
2019-02-04 9:02 ` tip-bot for Hidetoshi Seto [this message]
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