* Re: [PATCH] sched: fix should_resched() to avoid do schedule in atomic [not found] <1347937984-5817-1-git-send-email-wangyun@linux.vnet.ibm.com> @ 2012-09-26 3:41 ` Michael Wang 2012-10-06 9:06 ` Michael Wang 2012-10-09 2:20 ` Michael Wang 1 sibling, 1 reply; 4+ messages in thread From: Michael Wang @ 2012-09-26 3:41 UTC (permalink / raw) To: Michael Wang; +Cc: linux-kernel, peterz, mingo, svaidy, wfg On 09/18/2012 11:13 AM, Michael Wang wrote: > This patch try to fix the BUG: > > [ 0.043953] BUG: scheduling while atomic: swapper/0/1/0x10000002 > [ 0.044017] no locks held by swapper/0/1. > [ 0.044692] Pid: 1, comm: swapper/0 Not tainted 3.6.0-rc1-00420-gb7aebb9 #34 > [ 0.045861] Call Trace: > [ 0.048071] [<c106361e>] __schedule_bug+0x5e/0x70 > [ 0.048890] [<c1b28701>] __schedule+0x91/0xb10 > [ 0.049660] [<c14472ea>] ? vsnprintf+0x33a/0x450 > [ 0.050444] [<c1060006>] ? lg_local_lock+0x6/0x70 > [ 0.051256] [<c14fb5b1>] ? wait_for_xmitr+0x31/0x90 > [ 0.052019] [<c144fd55>] ? do_raw_spin_unlock+0xa5/0xf0 > [ 0.052903] [<c1b2a532>] ? _raw_spin_unlock+0x22/0x30 > [ 0.053759] [<c105cdbb>] ? up+0x1b/0x70 > [ 0.054421] [<c1065d6b>] __cond_resched+0x1b/0x30 > [ 0.055228] [<c1b292d5>] _cond_resched+0x45/0x50 > [ 0.056020] [<c1b26c58>] mutex_lock_nested+0x28/0x370 > [ 0.056884] [<c1034222>] ? console_unlock+0x3a2/0x4e0 > [ 0.057741] [<c1ac8559>] __irq_alloc_descs+0x39/0x1c0 > [ 0.058589] [<c10223bc>] io_apic_setup_irq_pin+0x2c/0x310 > [ 0.060042] [<c20638df>] setup_IO_APIC+0x101/0x744 > [ 0.060878] [<c1021d51>] ? clear_IO_APIC+0x31/0x50 > [ 0.061695] [<c20600f4>] native_smp_prepare_cpus+0x538/0x680 > [ 0.062644] [<c2056a91>] ? do_one_initcall+0x12c/0x12c > [ 0.063517] [<c2056a91>] ? do_one_initcall+0x12c/0x12c > [ 0.064016] [<c2056adc>] kernel_init+0x4b/0x17f > [ 0.064790] [<c2056a91>] ? do_one_initcall+0x12c/0x12c > [ 0.065660] [<c1b2bbd6>] kernel_thread_helper+0x6/0x10 > > The process to trigger the BUG is: > > native_smp_prepare_cpus() > preempt_disable() //preempt_count++ > __irq_alloc_descs() > mutex_lock() > might_sleep() //should_resched() return true > __schedule() > preempt_disable() //preempt_count++ > schedule_bug() //preempt_count > 1, report bug > > So the issue is that should_resched() should not return true while the preempt > already disabled. Hi, Peter Could we use this solution to fix the bug? Regards, Michael Wang > > This patch will fix the issue, then might_sleep() won't do schedule in atomic > any more. > > Reported-by: Fengguang Wu <wfg@linux.intel.com> > Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com> > --- > kernel/sched/core.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index b38f00e..2b7cd15 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -4171,7 +4171,7 @@ SYSCALL_DEFINE0(sched_yield) > > static inline int should_resched(void) > { > - return need_resched() && !(preempt_count() & PREEMPT_ACTIVE); > + return need_resched() && !preempt_count(); > } > > static void __cond_resched(void) > ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] sched: fix should_resched() to avoid do schedule in atomic 2012-09-26 3:41 ` [PATCH] sched: fix should_resched() to avoid do schedule in atomic Michael Wang @ 2012-10-06 9:06 ` Michael Wang 2012-10-06 9:12 ` Michael Wang 0 siblings, 1 reply; 4+ messages in thread From: Michael Wang @ 2012-10-06 9:06 UTC (permalink / raw) To: Michael Wang; +Cc: linux-kernel, peterz, mingo, svaidy, wfg On 09/26/2012 11:41 AM, Michael Wang wrote: > On 09/18/2012 11:13 AM, Michael Wang wrote: >> This patch try to fix the BUG: >> >> [ 0.043953] BUG: scheduling while atomic: swapper/0/1/0x10000002 >> [ 0.044017] no locks held by swapper/0/1. >> [ 0.044692] Pid: 1, comm: swapper/0 Not tainted 3.6.0-rc1-00420-gb7aebb9 #34 >> [ 0.045861] Call Trace: >> [ 0.048071] [<c106361e>] __schedule_bug+0x5e/0x70 >> [ 0.048890] [<c1b28701>] __schedule+0x91/0xb10 >> [ 0.049660] [<c14472ea>] ? vsnprintf+0x33a/0x450 >> [ 0.050444] [<c1060006>] ? lg_local_lock+0x6/0x70 >> [ 0.051256] [<c14fb5b1>] ? wait_for_xmitr+0x31/0x90 >> [ 0.052019] [<c144fd55>] ? do_raw_spin_unlock+0xa5/0xf0 >> [ 0.052903] [<c1b2a532>] ? _raw_spin_unlock+0x22/0x30 >> [ 0.053759] [<c105cdbb>] ? up+0x1b/0x70 >> [ 0.054421] [<c1065d6b>] __cond_resched+0x1b/0x30 >> [ 0.055228] [<c1b292d5>] _cond_resched+0x45/0x50 >> [ 0.056020] [<c1b26c58>] mutex_lock_nested+0x28/0x370 >> [ 0.056884] [<c1034222>] ? console_unlock+0x3a2/0x4e0 >> [ 0.057741] [<c1ac8559>] __irq_alloc_descs+0x39/0x1c0 >> [ 0.058589] [<c10223bc>] io_apic_setup_irq_pin+0x2c/0x310 >> [ 0.060042] [<c20638df>] setup_IO_APIC+0x101/0x744 >> [ 0.060878] [<c1021d51>] ? clear_IO_APIC+0x31/0x50 >> [ 0.061695] [<c20600f4>] native_smp_prepare_cpus+0x538/0x680 >> [ 0.062644] [<c2056a91>] ? do_one_initcall+0x12c/0x12c >> [ 0.063517] [<c2056a91>] ? do_one_initcall+0x12c/0x12c >> [ 0.064016] [<c2056adc>] kernel_init+0x4b/0x17f >> [ 0.064790] [<c2056a91>] ? do_one_initcall+0x12c/0x12c >> [ 0.065660] [<c1b2bbd6>] kernel_thread_helper+0x6/0x10 >> >> The process to trigger the BUG is: >> >> native_smp_prepare_cpus() >> preempt_disable() //preempt_count++ >> __irq_alloc_descs() >> mutex_lock() >> might_sleep() //should_resched() return true >> __schedule() >> preempt_disable() //preempt_count++ >> schedule_bug() //preempt_count > 1, report bug >> >> So the issue is that should_resched() should not return true while the preempt >> already disabled. > > Hi, Peter > > Could we use this solution to fix the bug? Please tell me if it's wrong, I really want to help fix it. Regards, Michael Wang > > Regards, > Michael Wang > >> >> This patch will fix the issue, then might_sleep() won't do schedule in atomic >> any more. >> >> Reported-by: Fengguang Wu <wfg@linux.intel.com> >> Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com> >> --- >> kernel/sched/core.c | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/kernel/sched/core.c b/kernel/sched/core.c >> index b38f00e..2b7cd15 100644 >> --- a/kernel/sched/core.c >> +++ b/kernel/sched/core.c >> @@ -4171,7 +4171,7 @@ SYSCALL_DEFINE0(sched_yield) >> >> static inline int should_resched(void) >> { >> - return need_resched() && !(preempt_count() & PREEMPT_ACTIVE); >> + return need_resched() && !preempt_count(); >> } >> >> static void __cond_resched(void) >> > ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] sched: fix should_resched() to avoid do schedule in atomic 2012-10-06 9:06 ` Michael Wang @ 2012-10-06 9:12 ` Michael Wang 0 siblings, 0 replies; 4+ messages in thread From: Michael Wang @ 2012-10-06 9:12 UTC (permalink / raw) To: Peter Zijlstra; +Cc: linux-kernel, mingo, svaidy, wfg On 10/06/2012 05:06 PM, Michael Wang wrote: > On 09/26/2012 11:41 AM, Michael Wang wrote: >> On 09/18/2012 11:13 AM, Michael Wang wrote: >>> This patch try to fix the BUG: >>> >>> [ 0.043953] BUG: scheduling while atomic: swapper/0/1/0x10000002 >>> [ 0.044017] no locks held by swapper/0/1. >>> [ 0.044692] Pid: 1, comm: swapper/0 Not tainted 3.6.0-rc1-00420-gb7aebb9 #34 >>> [ 0.045861] Call Trace: >>> [ 0.048071] [<c106361e>] __schedule_bug+0x5e/0x70 >>> [ 0.048890] [<c1b28701>] __schedule+0x91/0xb10 >>> [ 0.049660] [<c14472ea>] ? vsnprintf+0x33a/0x450 >>> [ 0.050444] [<c1060006>] ? lg_local_lock+0x6/0x70 >>> [ 0.051256] [<c14fb5b1>] ? wait_for_xmitr+0x31/0x90 >>> [ 0.052019] [<c144fd55>] ? do_raw_spin_unlock+0xa5/0xf0 >>> [ 0.052903] [<c1b2a532>] ? _raw_spin_unlock+0x22/0x30 >>> [ 0.053759] [<c105cdbb>] ? up+0x1b/0x70 >>> [ 0.054421] [<c1065d6b>] __cond_resched+0x1b/0x30 >>> [ 0.055228] [<c1b292d5>] _cond_resched+0x45/0x50 >>> [ 0.056020] [<c1b26c58>] mutex_lock_nested+0x28/0x370 >>> [ 0.056884] [<c1034222>] ? console_unlock+0x3a2/0x4e0 >>> [ 0.057741] [<c1ac8559>] __irq_alloc_descs+0x39/0x1c0 >>> [ 0.058589] [<c10223bc>] io_apic_setup_irq_pin+0x2c/0x310 >>> [ 0.060042] [<c20638df>] setup_IO_APIC+0x101/0x744 >>> [ 0.060878] [<c1021d51>] ? clear_IO_APIC+0x31/0x50 >>> [ 0.061695] [<c20600f4>] native_smp_prepare_cpus+0x538/0x680 >>> [ 0.062644] [<c2056a91>] ? do_one_initcall+0x12c/0x12c >>> [ 0.063517] [<c2056a91>] ? do_one_initcall+0x12c/0x12c >>> [ 0.064016] [<c2056adc>] kernel_init+0x4b/0x17f >>> [ 0.064790] [<c2056a91>] ? do_one_initcall+0x12c/0x12c >>> [ 0.065660] [<c1b2bbd6>] kernel_thread_helper+0x6/0x10 >>> >>> The process to trigger the BUG is: >>> >>> native_smp_prepare_cpus() >>> preempt_disable() //preempt_count++ >>> __irq_alloc_descs() >>> mutex_lock() >>> might_sleep() //should_resched() return true >>> __schedule() >>> preempt_disable() //preempt_count++ >>> schedule_bug() //preempt_count > 1, report bug >>> >>> So the issue is that should_resched() should not return true while the preempt >>> already disabled. >> >> Hi, Peter >> >> Could we use this solution to fix the bug? > > Please tell me if it's wrong, I really want to help fix it. Reset the destination, sorry for the terrible mailing skill... Regards, Michael Wang > > Regards, > Michael Wang > >> >> Regards, >> Michael Wang >> >>> >>> This patch will fix the issue, then might_sleep() won't do schedule in atomic >>> any more. >>> >>> Reported-by: Fengguang Wu <wfg@linux.intel.com> >>> Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com> >>> --- >>> kernel/sched/core.c | 2 +- >>> 1 files changed, 1 insertions(+), 1 deletions(-) >>> >>> diff --git a/kernel/sched/core.c b/kernel/sched/core.c >>> index b38f00e..2b7cd15 100644 >>> --- a/kernel/sched/core.c >>> +++ b/kernel/sched/core.c >>> @@ -4171,7 +4171,7 @@ SYSCALL_DEFINE0(sched_yield) >>> >>> static inline int should_resched(void) >>> { >>> - return need_resched() && !(preempt_count() & PREEMPT_ACTIVE); >>> + return need_resched() && !preempt_count(); >>> } >>> >>> static void __cond_resched(void) >>> >> > ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] sched: fix should_resched() to avoid do schedule in atomic [not found] <1347937984-5817-1-git-send-email-wangyun@linux.vnet.ibm.com> 2012-09-26 3:41 ` [PATCH] sched: fix should_resched() to avoid do schedule in atomic Michael Wang @ 2012-10-09 2:20 ` Michael Wang 1 sibling, 0 replies; 4+ messages in thread From: Michael Wang @ 2012-10-09 2:20 UTC (permalink / raw) To: Peter Zijlstra; +Cc: linux-kernel, mingo, wfg On 09/18/2012 11:13 AM, Michael Wang wrote: > This patch try to fix the BUG: > > [ 0.043953] BUG: scheduling while atomic: swapper/0/1/0x10000002 > [ 0.044017] no locks held by swapper/0/1. > [ 0.044692] Pid: 1, comm: swapper/0 Not tainted 3.6.0-rc1-00420-gb7aebb9 #34 > [ 0.045861] Call Trace: > [ 0.048071] [<c106361e>] __schedule_bug+0x5e/0x70 > [ 0.048890] [<c1b28701>] __schedule+0x91/0xb10 > [ 0.049660] [<c14472ea>] ? vsnprintf+0x33a/0x450 > [ 0.050444] [<c1060006>] ? lg_local_lock+0x6/0x70 > [ 0.051256] [<c14fb5b1>] ? wait_for_xmitr+0x31/0x90 > [ 0.052019] [<c144fd55>] ? do_raw_spin_unlock+0xa5/0xf0 > [ 0.052903] [<c1b2a532>] ? _raw_spin_unlock+0x22/0x30 > [ 0.053759] [<c105cdbb>] ? up+0x1b/0x70 > [ 0.054421] [<c1065d6b>] __cond_resched+0x1b/0x30 > [ 0.055228] [<c1b292d5>] _cond_resched+0x45/0x50 > [ 0.056020] [<c1b26c58>] mutex_lock_nested+0x28/0x370 > [ 0.056884] [<c1034222>] ? console_unlock+0x3a2/0x4e0 > [ 0.057741] [<c1ac8559>] __irq_alloc_descs+0x39/0x1c0 > [ 0.058589] [<c10223bc>] io_apic_setup_irq_pin+0x2c/0x310 > [ 0.060042] [<c20638df>] setup_IO_APIC+0x101/0x744 > [ 0.060878] [<c1021d51>] ? clear_IO_APIC+0x31/0x50 > [ 0.061695] [<c20600f4>] native_smp_prepare_cpus+0x538/0x680 > [ 0.062644] [<c2056a91>] ? do_one_initcall+0x12c/0x12c > [ 0.063517] [<c2056a91>] ? do_one_initcall+0x12c/0x12c > [ 0.064016] [<c2056adc>] kernel_init+0x4b/0x17f > [ 0.064790] [<c2056a91>] ? do_one_initcall+0x12c/0x12c > [ 0.065660] [<c1b2bbd6>] kernel_thread_helper+0x6/0x10 > > The process to trigger the BUG is: > > native_smp_prepare_cpus() > preempt_disable() //preempt_count++ > __irq_alloc_descs() > mutex_lock() > might_sleep() //should_resched() return true > __schedule() > preempt_disable() //preempt_count++ > schedule_bug() //preempt_count > 1, report bug > > So the issue is that should_resched() should not return true while the preempt > already disabled. > > This patch will fix the issue, then might_sleep() won't do schedule in atomic > any more. Could I get some comments on the patch? Regards, Michael Wang > > Reported-by: Fengguang Wu <wfg@linux.intel.com> > Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com> > --- > kernel/sched/core.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index b38f00e..2b7cd15 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -4171,7 +4171,7 @@ SYSCALL_DEFINE0(sched_yield) > > static inline int should_resched(void) > { > - return need_resched() && !(preempt_count() & PREEMPT_ACTIVE); > + return need_resched() && !preempt_count(); > } > > static void __cond_resched(void) > ^ permalink raw reply [flat|nested] 4+ messages in thread
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2012-09-26 3:41 ` [PATCH] sched: fix should_resched() to avoid do schedule in atomic Michael Wang
2012-10-06 9:06 ` Michael Wang
2012-10-06 9:12 ` Michael Wang
2012-10-09 2:20 ` Michael Wang
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