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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2022-12-01 19:33:09 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-03-03 11:52:23 +0100
commitf2173508b195958c97c4a1da28389dc7544d1bc1 (patch)
tree6458247c331919f9e886100fc655d9d82627ece1
parent0c2f28f01fce6d5eb34f3e664824d50d563ee720 (diff)
downloadlinux-f2173508b195958c97c4a1da28389dc7544d1bc1.tar.gz
PM: sleep: Avoid using pr_cont() in the tasks freezing code
commit a449dfbfc0894676ad0aa1873383265047529e3a upstream.

Using pr_cont() in the tasks freezing code related to system-wide
suspend and hibernation is problematic, because the continuation
messages printed there are susceptible to interspersing with other
unrelated messages which results in output that is hard to
understand.

Address this issue by modifying try_to_freeze_tasks() to print
messages that don't require continuations and adjusting its
callers accordingly.

Reported-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--kernel/power/process.c21
1 files changed, 8 insertions, 13 deletions
diff --git a/kernel/power/process.c b/kernel/power/process.c
index ddd9988327fe..beeab7f9fac8 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -27,6 +27,8 @@ unsigned int __read_mostly freeze_timeout_msecs = 20 * MSEC_PER_SEC;
 
 static int try_to_freeze_tasks(bool user_only)
 {
+	const char *what = user_only ? "user space processes" :
+					"remaining freezable tasks";
 	struct task_struct *g, *p;
 	unsigned long end_time;
 	unsigned int todo;
@@ -36,6 +38,8 @@ static int try_to_freeze_tasks(bool user_only)
 	bool wakeup = false;
 	int sleep_usecs = USEC_PER_MSEC;
 
+	pr_info("Freezing %s\n", what);
+
 	start = ktime_get_boottime();
 
 	end_time = jiffies + msecs_to_jiffies(freeze_timeout_msecs);
@@ -82,7 +86,6 @@ static int try_to_freeze_tasks(bool user_only)
 	elapsed_msecs = ktime_to_ms(elapsed);
 
 	if (todo) {
-		pr_cont("\n");
 		pr_err("Freezing of tasks %s after %d.%03d seconds "
 		       "(%d tasks refusing to freeze, wq_busy=%d):\n",
 		       wakeup ? "aborted" : "failed",
@@ -101,8 +104,8 @@ static int try_to_freeze_tasks(bool user_only)
 			read_unlock(&tasklist_lock);
 		}
 	} else {
-		pr_cont("(elapsed %d.%03d seconds) ", elapsed_msecs / 1000,
-			elapsed_msecs % 1000);
+		pr_info("Freezing %s completed (elapsed %d.%03d seconds)\n",
+			what, elapsed_msecs / 1000, elapsed_msecs % 1000);
 	}
 
 	return todo ? -EBUSY : 0;
@@ -130,14 +133,11 @@ int freeze_processes(void)
 		static_branch_inc(&freezer_active);
 
 	pm_wakeup_clear(0);
-	pr_info("Freezing user space processes ... ");
 	pm_freezing = true;
 	error = try_to_freeze_tasks(true);
-	if (!error) {
+	if (!error)
 		__usermodehelper_set_disable_depth(UMH_DISABLED);
-		pr_cont("done.");
-	}
-	pr_cont("\n");
+
 	BUG_ON(in_atomic());
 
 	/*
@@ -166,14 +166,9 @@ int freeze_kernel_threads(void)
 {
 	int error;
 
-	pr_info("Freezing remaining freezable tasks ... ");
-
 	pm_nosig_freezing = true;
 	error = try_to_freeze_tasks(false);
-	if (!error)
-		pr_cont("done.");
 
-	pr_cont("\n");
 	BUG_ON(in_atomic());
 
 	if (error)