From: Qian Cai <cai@redhat.com>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Qian Cai <cai@redhat.com>
Subject: [PATCH] arm64/smp: Move rcu_cpu_starting() earlier
Date: Wed, 28 Oct 2020 14:26:14 -0400 [thread overview]
Message-ID: <20201028182614.13655-1-cai@redhat.com> (raw)
The call to rcu_cpu_starting() in secondary_start_kernel() is not early
enough in the CPU-hotplug onlining process, which results in lockdep
splats as follows:
WARNING: suspicious RCU usage
-----------------------------
kernel/locking/lockdep.c:3497 RCU-list traversed in non-reader section!!
other info that might help us debug this:
RCU used illegally from offline CPU!
rcu_scheduler_active = 1, debug_locks = 1
no locks held by swapper/1/0.
Call trace:
dump_backtrace+0x0/0x3c8
show_stack+0x14/0x60
dump_stack+0x14c/0x1c4
lockdep_rcu_suspicious+0x134/0x14c
__lock_acquire+0x1c30/0x2600
lock_acquire+0x274/0xc48
_raw_spin_lock+0xc8/0x140
vprintk_emit+0x90/0x3d0
vprintk_default+0x34/0x40
vprintk_func+0x378/0x590
printk+0xa8/0xd4
__cpuinfo_store_cpu+0x71c/0x868
cpuinfo_store_cpu+0x2c/0xc8
secondary_start_kernel+0x244/0x318
This is avoided by moving the call to rcu_cpu_starting up near the
beginning of the secondary_start_kernel() function.
Link: https://lore.kernel.org/lkml/160223032121.7002.1269740091547117869.tip-bot2@tip-bot2/
Signed-off-by: Qian Cai <cai@redhat.com>
---
arch/arm64/kernel/smp.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 82e75fc2c903..09c96f57818c 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -222,6 +222,7 @@ asmlinkage notrace void secondary_start_kernel(void)
if (system_uses_irq_prio_masking())
init_gic_priority_masking();
+ rcu_cpu_starting(cpu);
preempt_disable();
trace_hardirqs_off();
--
2.28.0
WARNING: multiple messages have this Message-ID (diff)
From: Qian Cai <cai@redhat.com>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
linux-kernel@vger.kernel.org, Qian Cai <cai@redhat.com>,
Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64/smp: Move rcu_cpu_starting() earlier
Date: Wed, 28 Oct 2020 14:26:14 -0400 [thread overview]
Message-ID: <20201028182614.13655-1-cai@redhat.com> (raw)
The call to rcu_cpu_starting() in secondary_start_kernel() is not early
enough in the CPU-hotplug onlining process, which results in lockdep
splats as follows:
WARNING: suspicious RCU usage
-----------------------------
kernel/locking/lockdep.c:3497 RCU-list traversed in non-reader section!!
other info that might help us debug this:
RCU used illegally from offline CPU!
rcu_scheduler_active = 1, debug_locks = 1
no locks held by swapper/1/0.
Call trace:
dump_backtrace+0x0/0x3c8
show_stack+0x14/0x60
dump_stack+0x14c/0x1c4
lockdep_rcu_suspicious+0x134/0x14c
__lock_acquire+0x1c30/0x2600
lock_acquire+0x274/0xc48
_raw_spin_lock+0xc8/0x140
vprintk_emit+0x90/0x3d0
vprintk_default+0x34/0x40
vprintk_func+0x378/0x590
printk+0xa8/0xd4
__cpuinfo_store_cpu+0x71c/0x868
cpuinfo_store_cpu+0x2c/0xc8
secondary_start_kernel+0x244/0x318
This is avoided by moving the call to rcu_cpu_starting up near the
beginning of the secondary_start_kernel() function.
Link: https://lore.kernel.org/lkml/160223032121.7002.1269740091547117869.tip-bot2@tip-bot2/
Signed-off-by: Qian Cai <cai@redhat.com>
---
arch/arm64/kernel/smp.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 82e75fc2c903..09c96f57818c 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -222,6 +222,7 @@ asmlinkage notrace void secondary_start_kernel(void)
if (system_uses_irq_prio_masking())
init_gic_priority_masking();
+ rcu_cpu_starting(cpu);
preempt_disable();
trace_hardirqs_off();
--
2.28.0
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next reply other threads:[~2020-10-28 22:29 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-28 18:26 Qian Cai [this message]
2020-10-28 18:26 ` [PATCH] arm64/smp: Move rcu_cpu_starting() earlier Qian Cai
2020-10-28 21:00 ` Paul E. McKenney
2020-10-28 21:00 ` Paul E. McKenney
2020-10-29 9:10 ` Will Deacon
2020-10-29 9:10 ` Will Deacon
2020-10-29 13:17 ` Qian Cai
2020-10-29 13:17 ` Qian Cai
2020-10-30 8:15 ` Will Deacon
2020-10-30 8:15 ` Will Deacon
2020-10-29 14:09 ` Paul E. McKenney
2020-10-29 14:09 ` Paul E. McKenney
2020-10-30 16:33 ` Will Deacon
2020-10-30 16:33 ` Will Deacon
2020-11-05 22:22 ` Will Deacon
2020-11-05 22:22 ` Will Deacon
2020-11-05 23:02 ` Qian Cai
2020-11-05 23:02 ` Qian Cai
2020-11-05 23:28 ` Paul E. McKenney
2020-11-05 23:28 ` Paul E. McKenney
2020-11-06 2:15 ` Qian Cai
2020-11-06 2:15 ` Qian Cai
2020-11-06 4:07 ` Paul E. McKenney
2020-11-06 4:07 ` Paul E. McKenney
2020-11-06 10:37 ` Will Deacon
2020-11-06 10:37 ` Will Deacon
2020-11-06 12:48 ` Qian Cai
2020-11-06 12:48 ` Qian Cai
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