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authorAaron Tomlin <atomlin@redhat.com>2014-01-20 17:34:13 +0000
committerIngo Molnar <mingo@kernel.org>2014-01-25 12:13:33 +0100
commit270750dbc18a71b23d660df110e433ff9616a2d4 (patch)
tree9b0400fc3713bd02d31835e8d0315cfbd7ccd912 /kernel
parent2397efb1bb17595b35f31abb40d95074ebc04f1b (diff)
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hung_task: Display every hung task warning
When khungtaskd detects hung tasks, it prints out backtraces from a number of those tasks. Limiting the number of backtraces being printed out can result in the user not seeing the information necessary to debug the issue. The hung_task_warnings sysctl controls this feature. This patch makes it possible for hung_task_warnings to accept a special value to print an unlimited number of backtraces when khungtaskd detects hung tasks. The special value is -1. To use this value it is necessary to change types from ulong to int. Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Cc: oleg@redhat.com Link: http://lkml.kernel.org/r/1390239253-24030-3-git-send-email-atomlin@redhat.com [ Build warning fix. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/hung_task.c6
-rw-r--r--kernel/sysctl.c8
2 files changed, 9 insertions, 5 deletions
diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index 9328b80eaf14..0b9c169d577f 100644
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -37,7 +37,7 @@ int __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT;
*/
unsigned long __read_mostly sysctl_hung_task_timeout_secs = CONFIG_DEFAULT_HUNG_TASK_TIMEOUT;
-unsigned long __read_mostly sysctl_hung_task_warnings = 10;
+int __read_mostly sysctl_hung_task_warnings = 10;
static int __read_mostly did_panic;
@@ -98,7 +98,9 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
if (!sysctl_hung_task_warnings)
return;
- sysctl_hung_task_warnings--;
+
+ if (sysctl_hung_task_warnings > 0)
+ sysctl_hung_task_warnings--;
/*
* Ok, the task did not get scheduled for more than 2 minutes,
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index c398a58673a7..dd5b4496637e 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -122,7 +122,8 @@ extern int blk_iopoll_enabled;
static int sixty = 60;
#endif
-static int neg_one = -1;
+static int __maybe_unused neg_one = -1;
+
static int zero;
static int __maybe_unused one = 1;
static int __maybe_unused two = 2;
@@ -978,9 +979,10 @@ static struct ctl_table kern_table[] = {
{
.procname = "hung_task_warnings",
.data = &sysctl_hung_task_warnings,
- .maxlen = sizeof(unsigned long),
+ .maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = proc_doulongvec_minmax,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &neg_one,
},
#endif
#ifdef CONFIG_COMPAT