From 41e85ce8220c6e5fdef706fda6696cd291115b63 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Thu, 1 Aug 2013 18:59:41 +0200 Subject: [PATCH] hung_task debugging: Print more info when reporting the problem printk(KERN_ERR) from check_hung_task() likely means we have a bug, but unlike BUG_ON()/WARN_ON ()it doesn't show the kernel version, this complicates the bug-reports investigation. Add the additional pr_err() to print tainted/release/version like dump_stack_print_info() does, the output becomes: INFO: task perl:504 blocked for more than 2 seconds. Not tainted 3.11.0-rc1-10367-g136bb46-dirty #1763 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ... While at it, turn the old printk's into pr_err(). Signed-off-by: Oleg Nesterov Cc: ahecox@redhat.com Cc: Christopher Williams Cc: dwysocha@redhat.com Cc: gavin@redhat.com Cc: Mandeep Singh Baines Cc: nshi@redhat.com Cc: Linus Torvalds Cc: Andrew Morton Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20130801165941.GA17544@redhat.com Signed-off-by: Ingo Molnar --- kernel/hung_task.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/kernel/hung_task.c b/kernel/hung_task.c index 6df614912b9d..3e97fb126e6b 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -15,6 +15,7 @@ #include #include #include +#include /* * The number of tasks checked: @@ -99,10 +100,14 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) * Ok, the task did not get scheduled for more than 2 minutes, * complain: */ - printk(KERN_ERR "INFO: task %s:%d blocked for more than " - "%ld seconds.\n", t->comm, t->pid, timeout); - printk(KERN_ERR "\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\"" - " disables this message.\n"); + pr_err("INFO: task %s:%d blocked for more than %ld seconds.\n", + t->comm, t->pid, timeout); + pr_err(" %s %s %.*s\n", + print_tainted(), init_utsname()->release, + (int)strcspn(init_utsname()->version, " "), + init_utsname()->version); + pr_err("\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\"" + " disables this message.\n"); sched_show_task(t); debug_show_held_locks(t);