From a449dfbfc0894676ad0aa1873383265047529e3a Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 1 Dec 2022 19:33:09 +0100 Subject: PM: sleep: Avoid using pr_cont() in the tasks freezing code MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Rafael J. Wysocki Reviewed-by: Petr Mladek --- kernel/power/process.c | 21 ++++++++------------- 1 file changed, 8 insertions(+), 13 deletions(-) (limited to 'kernel/power') 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) -- cgit v1.2.3