linux-kernel - [PATCH V2 2/8] timer: don't migrate pinned timers

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]

Date:	Fri,  4 Apr 2014 14:05:29 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	tglx@...utronix.de, fweisbec@...il.com, peterz@...radead.org,
	mingo@...nel.org, tj@...nel.org, lizefan@...wei.com
Cc:	linaro-kernel@...ts.linaro.org, linaro-networking@...aro.org,
	Arvind.Chauhan@....com, linux-kernel@...r.kernel.org,
	cgroups@...r.kernel.org, Viresh Kumar <viresh.kumar@...aro.org>
Subject: [PATCH V2 2/8] timer: don't migrate pinned timers

migrate_timer() is called when a CPU goes down and its timers are required to be
migrated to some other CPU. Its the responsibility of the users of the timer to
remove it before control reaches to migrate_timers().

As these were the pinned timers, the best we can do is: don't migrate these and
report to the user as well.

That's all this patch does.

Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
 kernel/timer.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/kernel/timer.c b/kernel/timer.c
index e8bcaff..6c3a371 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1606,11 +1606,21 @@ static int init_timers_cpu(int cpu)
 static void migrate_timer_list(struct tvec_base *new_base, struct list_head *head)
 {
 	struct timer_list *timer;
+	int is_pinned;
 
 	while (!list_empty(head)) {
 		timer = list_first_entry(head, struct timer_list, entry);
 		/* We ignore the accounting on the dying cpu */
 		detach_timer(timer, false);
+
+		is_pinned = tbase_get_pinned(timer->base);
+
+		/* Check if CPU still has pinned timers */
+		if (unlikely(WARN(is_pinned,
+				  "%s: can't migrate pinned timer: %p, deactivating it\n",
+				  __func__, timer)))
+			continue;
+
 		timer_set_base(timer, new_base);
 		internal_add_timer(new_base, timer);
 	}
-- 
1.7.12.rc2.18.g61b472e

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/