From: Greg Kroah-Hartman Date: Mon, 19 Nov 2007 23:19:49 +0000 (-0800) Subject: add queue-2.6.23/softlockup-watchdog-fixes-and-cleanups.patch X-Git-Tag: v2.6.22.14~5 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=0aa72e40b7d6646e81170c6f075b3452e3dcd67e;p=thirdparty%2Fkernel%2Fstable-queue.git add queue-2.6.23/softlockup-watchdog-fixes-and-cleanups.patch --- diff --git a/queue-2.6.23/series b/queue-2.6.23/series index 28363c7bffd..ab0cbd8091d 100644 --- a/queue-2.6.23/series +++ b/queue-2.6.23/series @@ -22,3 +22,4 @@ x86-nx-bit-handling-in-change-page-attr.patch x98-return-correct-error-code-from-child-rip.patch ntp-fix-sync-cmos-clock-typo.patch x86-fix-rtc-locking.patch +softlockup-watchdog-fixes-and-cleanups.patch diff --git a/queue-2.6.23/softlockup-watchdog-fixes-and-cleanups.patch b/queue-2.6.23/softlockup-watchdog-fixes-and-cleanups.patch new file mode 100644 index 00000000000..0704dcfac58 --- /dev/null +++ b/queue-2.6.23/softlockup-watchdog-fixes-and-cleanups.patch @@ -0,0 +1,195 @@ +From mingo@elte.hu Sat Nov 17 16:56:05 2007 +From: Ingo Molnar +Date: Sun, 18 Nov 2007 01:55:38 +0100 +Subject: softlockup watchdog fixes and cleanups +To: Greg KH +Cc: David , Jeremy Fitzhardinge , gregkh@suse.de, Javier Kohen , Andrew Morton , linux-kernel@vger.kernel.org, stable@kernel.org +Message-ID: <20071118005538.GD26865@elte.hu> +Content-Disposition: inline + +From: Ingo Molnar + + +This is a merge of commits a5f2ce3c6024a5bb895647b6bd88ecae5001020a and +43581a10075492445f65234384210492ff333eba in mainline to fix a warning in +the 2.6.23.3 kernel release. + +softlockup watchdog: style cleanups + +kernel/softirq.c grew a few style uncleanlinesses in the past few +months, clean that up. No functional changes: + +text data bss dec hex filename +1126 76 4 1206 4b6 softlockup.o.before +1129 76 4 1209 4b9 softlockup.o.after + +( the 3 bytes .text increase is due to the "<1>" appended to one of +the printk messages. ) + +Signed-off-by: Ingo Molnar +Signed-off-by: Andrew Morton +Signed-off-by: Linus Torvalds + + +softlockup: improve debug output + +Improve the debuggability of kernel lockups by enhancing the debug +output of the softlockup detector: print the task that causes the lockup +and try to print a more intelligent backtrace. + +The old format was: + +BUG: soft lockup detected on CPU#1! +[] show_trace_log_lvl+0x19/0x2e +[] show_trace+0x12/0x14 +[] dump_stack+0x14/0x16 +[] softlockup_tick+0xbe/0xd0 +[] run_local_timers+0x12/0x14 +[] update_process_times+0x3e/0x63 +[] tick_sched_timer+0x7c/0xc0 +[] hrtimer_interrupt+0x135/0x1ba +[] smp_apic_timer_interrupt+0x6e/0x80 +[] apic_timer_interrupt+0x33/0x38 +[] syscall_call+0x7/0xb +======================= + +The new format is: + +BUG: soft lockup detected on CPU#1! [prctl:2363] + +Pid: 2363, comm: prctl +EIP: 0060:[] CPU: 1 +EIP is at sys_prctl+0x24/0x18c +EFLAGS: 00000213 Not tainted (2.6.22-cfs-v20 #26) +EAX: 00000001 EBX: 000003e7 ECX: 00000001 EDX: f6df0000 +ESI: 000003e7 EDI: 000003e7 EBP: f6df0fb0 DS: 007b ES: 007b FS: 00d8 +CR0: 8005003b CR2: 4d8c3340 CR3: 3731d000 CR4: 000006d0 +[] show_trace_log_lvl+0x19/0x2e +[] show_trace+0x12/0x14 +[] show_regs+0x1ab/0x1b3 +[] softlockup_tick+0xef/0x108 +[] run_local_timers+0x12/0x14 +[] update_process_times+0x3e/0x63 +[] tick_sched_timer+0x7c/0xc0 +[] hrtimer_interrupt+0x135/0x1ba +[] smp_apic_timer_interrupt+0x6e/0x80 +[] apic_timer_interrupt+0x33/0x38 +[] syscall_call+0x7/0xb +======================= + +Note that in the old format we only knew that some system call locked +up, we didnt know _which_. With the new format we know that it's at a +specific place in sys_prctl(). [which was where i created an artificial +kernel lockup to test the new format.] + +This is also useful if the lockup happens in user-space - the user-space +EIP (and other registers) will be printed too. (such a lockup would +either suggest that the task was running at SCHED_FIFO:99 and looping +for more than 10 seconds, or that the softlockup detector has a +false-positive.) + +The task name is printed too first, just in case we dont manage to print +a useful backtrace. + +[satyam@infradead.org: fix warning] +Signed-off-by: Ingo Molnar +Signed-off-by: Satyam Sharma +Signed-off-by: Andrew Morton +Signed-off-by: Linus Torvalds +Signed-off-by: Greg Kroah-Hartman + + +--- + kernel/softlockup.c | 37 +++++++++++++++++++++++-------------- + 1 file changed, 23 insertions(+), 14 deletions(-) + +--- a/kernel/softlockup.c ++++ b/kernel/softlockup.c +@@ -15,13 +15,16 @@ + #include + #include + ++#include ++ + static DEFINE_SPINLOCK(print_lock); + + static DEFINE_PER_CPU(unsigned long, touch_timestamp); + static DEFINE_PER_CPU(unsigned long, print_timestamp); + static DEFINE_PER_CPU(struct task_struct *, watchdog_task); + +-static int did_panic = 0; ++static int did_panic; ++int softlockup_thresh = 10; + + static int + softlock_panic(struct notifier_block *this, unsigned long event, void *ptr) +@@ -70,6 +73,7 @@ void softlockup_tick(void) + int this_cpu = smp_processor_id(); + unsigned long touch_timestamp = per_cpu(touch_timestamp, this_cpu); + unsigned long print_timestamp; ++ struct pt_regs *regs = get_irq_regs(); + unsigned long now; + + if (touch_timestamp == 0) { +@@ -99,21 +103,26 @@ void softlockup_tick(void) + wake_up_process(per_cpu(watchdog_task, this_cpu)); + + /* Warn about unreasonable 10+ seconds delays: */ +- if (now > (touch_timestamp + 10)) { +- per_cpu(print_timestamp, this_cpu) = touch_timestamp; ++ if (now <= (touch_timestamp + softlockup_thresh)) ++ return; ++ ++ per_cpu(print_timestamp, this_cpu) = touch_timestamp; + +- spin_lock(&print_lock); +- printk(KERN_ERR "BUG: soft lockup detected on CPU#%d!\n", +- this_cpu); ++ spin_lock(&print_lock); ++ printk(KERN_ERR "BUG: soft lockup - CPU#%d stuck for %lus! [%s:%d]\n", ++ this_cpu, now - touch_timestamp, ++ current->comm, current->pid); ++ if (regs) ++ show_regs(regs); ++ else + dump_stack(); +- spin_unlock(&print_lock); +- } ++ spin_unlock(&print_lock); + } + + /* + * The watchdog thread - runs every second and touches the timestamp. + */ +-static int watchdog(void * __bind_cpu) ++static int watchdog(void *__bind_cpu) + { + struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; + +@@ -151,13 +160,13 @@ cpu_callback(struct notifier_block *nfb, + BUG_ON(per_cpu(watchdog_task, hotcpu)); + p = kthread_create(watchdog, hcpu, "watchdog/%d", hotcpu); + if (IS_ERR(p)) { +- printk("watchdog for %i failed\n", hotcpu); ++ printk(KERN_ERR "watchdog for %i failed\n", hotcpu); + return NOTIFY_BAD; + } +- per_cpu(touch_timestamp, hotcpu) = 0; +- per_cpu(watchdog_task, hotcpu) = p; ++ per_cpu(touch_timestamp, hotcpu) = 0; ++ per_cpu(watchdog_task, hotcpu) = p; + kthread_bind(p, hotcpu); +- break; ++ break; + case CPU_ONLINE: + case CPU_ONLINE_FROZEN: + wake_up_process(per_cpu(watchdog_task, hotcpu)); +@@ -177,7 +186,7 @@ cpu_callback(struct notifier_block *nfb, + kthread_stop(p); + break; + #endif /* CONFIG_HOTPLUG_CPU */ +- } ++ } + return NOTIFY_OK; + } +