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authorQian Cai <cai@redhat.com>2020-10-28 14:26:14 -0400
committerWill Deacon <will@kernel.org>2020-10-30 08:13:18 +0000
commitce3d31ad3cac765484463b4f5a0b6b1f8f1a963e (patch)
tree52d2d66433766f2cc4f0ba90bad4b551137f657a /arch
parent96d389ca10110d7eefb46feb6af9a0c6832f78f5 (diff)
arm64/smp: Move rcu_cpu_starting() earlier
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. Signed-off-by: Qian Cai <cai@redhat.com> Acked-by: Paul E. McKenney <paulmck@kernel.org> Link: https://lore.kernel.org/lkml/160223032121.7002.1269740091547117869.tip-bot2@tip-bot2/ Link: https://lore.kernel.org/r/20201028182614.13655-1-cai@redhat.com Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/kernel/smp.c1
1 files changed, 1 insertions, 0 deletions
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();

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