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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 <oleg@redhat.com>
Cc: ahecox@redhat.com
Cc: Christopher Williams <cww@redhat.com>
Cc: dwysocha@redhat.com
Cc: gavin@redhat.com
Cc: Mandeep Singh Baines <msb@chromium.org>
Cc: nshi@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20130801165941.GA17544@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Oleg Nesterov 2013-08-01 18:59:41 +02:00 committed by Ingo Molnar
parent 2b48839722
commit 41e85ce822
1 changed files with 9 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
kernel/hung_task.c
View File

@ -15,6 +15,7 @@
#include <linux/lockdep.h>
#include <linux/export.h>
#include <linux/sysctl.h>
#include <linux/utsname.h>
/*
* 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);