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mips/smp: Call rcutree_report_cpu_starting() earlier 

commit 55702ec9603ebeffb15e6f7b113623fe1d8872f4 upstream.

rcutree_report_cpu_starting() must be called before
clockevents_register_device() to avoid the following lockdep splat triggered by
calling list_add() when CONFIG_PROVE_RCU_LIST=y:

  WARNING: suspicious RCU usage
  ...
  -----------------------------
  kernel/locking/lockdep.c:3680 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:
  [<ffffffff8012a434>] show_stack+0x64/0x158
  [<ffffffff80a93d98>] dump_stack_lvl+0x90/0xc4
  [<ffffffff801c9e9c>] __lock_acquire+0x1404/0x2940
  [<ffffffff801cbf3c>] lock_acquire+0x14c/0x448
  [<ffffffff80aa4260>] _raw_spin_lock_irqsave+0x50/0x88
  [<ffffffff8021e0c8>] clockevents_register_device+0x60/0x1e8
  [<ffffffff80130ff0>] r4k_clockevent_init+0x220/0x3a0
  [<ffffffff801339d0>] start_secondary+0x50/0x3b8

raw_smp_processor_id() is required in order to avoid calling into lockdep
before RCU has declared the CPU to be watched for readers.

See also commit 29368e0939 ("x86/smpboot:  Move rcu_cpu_starting() earlier"),
commit de5d9dae15 ("s390/smp: move rcu_cpu_starting() earlier") and commit
99f070b623 ("powerpc/smp: Call rcu_cpu_starting() earlier").

Signed-off-by: Stefan Wiehler <stefan.wiehler@nokia.com>
Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Stefan Wiehler 2023-11-06 13:12:07 +01:00 committed by Greg Kroah-Hartman
parent 16e1d4fa13
commit 45e565b55b
1 changed files with 2 additions and 2 deletions
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4
arch/mips/kernel/smp.c
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@ -333,10 +333,11 @@ early_initcall(mips_smp_ipi_init);
*/
asmlinkage void start_secondary(void)
{
unsigned int cpu;
unsigned int cpu = raw_smp_processor_id();
cpu_probe();
per_cpu_trap_init(false);
rcu_cpu_starting(cpu);
mips_clockevent_init();
mp_ops->init_secondary();
cpu_report();
@ -348,7 +349,6 @@ asmlinkage void start_secondary(void)
*/
calibrate_delay();
cpu = smp_processor_id();
cpu_data[cpu].udelay_val = loops_per_jiffy;
set_cpu_sibling_map(cpu);