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authorIngo Molnar <mingo@elte.hu>2008-01-25 21:08:02 +0100
committerIngo Molnar <mingo@elte.hu>2008-01-25 21:08:02 +0100
commit82a1fcb90287052aabfa235e7ffc693ea003fe69 (patch)
tree826b464a248bebe259fe787f7b8d17d5626cf2c5 /kernel/fork.c
parentd0d23b5432fe61229dd3641c5e94d4130bc4e61b (diff)
softlockup: automatically detect hung TASK_UNINTERRUPTIBLE tasks
this patch extends the soft-lockup detector to automatically detect hung TASK_UNINTERRUPTIBLE tasks. Such hung tasks are printed the following way: ------------------> INFO: task prctl:3042 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message prctl D fd5e3793 0 3042 2997 f6050f38 00000046 00000001 fd5e3793 00000009 c06d8264 c06dae80 00000286 f6050f40 f6050f00 f7d34d90 f7d34fc8 c1e1be80 00000001 f6050000 00000000 f7e92d00 00000286 f6050f18 c0489d1a f6050f40 00006605 00000000 c0133a5b Call Trace: [<c04883a5>] schedule_timeout+0x6d/0x8b [<c04883d8>] schedule_timeout_uninterruptible+0x15/0x17 [<c0133a76>] msleep+0x10/0x16 [<c0138974>] sys_prctl+0x30/0x1e2 [<c0104c52>] sysenter_past_esp+0x5f/0xa5 ======================= 2 locks held by prctl/3042: #0: (&sb->s_type->i_mutex_key#5){--..}, at: [<c0197d11>] do_fsync+0x38/0x7a #1: (jbd_handle){--..}, at: [<c01ca3d2>] journal_start+0xc7/0xe9 <------------------ the current default timeout is 120 seconds. Such messages are printed up to 10 times per bootup. If the system has crashed already then the messages are not printed. if lockdep is enabled then all held locks are printed as well. this feature is a natural extension to the softlockup-detector (kernel locked up without scheduling) and to the NMI watchdog (kernel locked up with IRQs disabled). [ Gautham R Shenoy <ego@in.ibm.com>: CPU hotplug fixes. ] [ Andrew Morton <akpm@linux-foundation.org>: build warning fix. ] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Diffstat (limited to 'kernel/fork.c')
-rw-r--r--kernel/fork.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 8dd8ff28100..09c0b90a69c 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1059,6 +1059,11 @@ static struct task_struct *copy_process(unsigned long clone_flags,
p->prev_utime = cputime_zero;
p->prev_stime = cputime_zero;
+#ifdef CONFIG_DETECT_SOFTLOCKUP
+ p->last_switch_count = 0;
+ p->last_switch_timestamp = 0;
+#endif
+
#ifdef CONFIG_TASK_XACCT
p->rchar = 0; /* I/O counter: bytes read */
p->wchar = 0; /* I/O counter: bytes written */