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| author | Stefan Wiehler <stefan.wiehler@nokia.com> | 2023-11-06 13:12:07 +0100 |
|---|---|---|
| committer | Thomas Bogendoerfer <tsbogend@alpha.franken.de> | 2023-12-05 18:43:05 +0100 |
| commit | 55702ec9603ebeffb15e6f7b113623fe1d8872f4 (patch) | |
| tree | d112e9f4e9aa5da5611e08217c7e2b901563b182 /arch | |
| parent | Linux 6.7-rc4 (diff) | |
| download | linux-55702ec9603ebeffb15e6f7b113623fe1d8872f4.tar.xz linux-55702ec9603ebeffb15e6f7b113623fe1d8872f4.zip | |
mips/smp: Call rcutree_report_cpu_starting() earlier
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 29368e093921 ("x86/smpboot: Move rcu_cpu_starting() earlier"),
commit de5d9dae150c ("s390/smp: move rcu_cpu_starting() earlier") and commit
99f070b62322 ("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>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/mips/kernel/smp.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c index 8fbef537fb88..82e2e051b416 100644 --- a/arch/mips/kernel/smp.c +++ b/arch/mips/kernel/smp.c @@ -351,10 +351,11 @@ 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); + rcutree_report_cpu_starting(cpu); mips_clockevent_init(); mp_ops->init_secondary(); cpu_report(); @@ -366,7 +367,6 @@ asmlinkage void start_secondary(void) */ calibrate_delay(); - cpu = smp_processor_id(); cpu_data[cpu].udelay_val = loops_per_jiffy; set_cpu_sibling_map(cpu); |