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| author |   Paul E. McKenney <paulmck@kernel.org> | 2020-10-20 21:13:55 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2020-11-19 19:37:16 -0800 |
| commit | 29368e09392123800e5e2bf0f3eda91f16972e52 (patch) | |
| tree | 20c9562edfbe013cc7a6207bb70413854425a572 /arch/x86/kernel/smpboot.c | |
| parent | rcu: Allow rcu_irq_enter_check_tick() from NMI (diff) | |
| download | linux-dev-29368e09392123800e5e2bf0f3eda91f16972e52.tar.xz linux-dev-29368e09392123800e5e2bf0f3eda91f16972e52.zip | |
x86/smpboot: Move rcu_cpu_starting() earlier
The call to rcu_cpu_starting() in mtrr_ap_init() is not early enough
in the CPU-hotplug onlining process, which results in lockdep splats
as follows:
=============================
WARNING: suspicious RCU usage
5.9.0+ #268 Not tainted
-----------------------------
kernel/kprobes.c:300 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.
stack backtrace:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.9.0+ #268
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.2-1ubuntu1 04/01/2014
Call Trace:
dump_stack+0x77/0x97
__is_insn_slot_addr+0x15d/0x170
kernel_text_address+0xba/0xe0
? get_stack_info+0x22/0xa0
__kernel_text_address+0x9/0x30
show_trace_log_lvl+0x17d/0x380
? dump_stack+0x77/0x97
dump_stack+0x77/0x97
__lock_acquire+0xdf7/0x1bf0
lock_acquire+0x258/0x3d0
? vprintk_emit+0x6d/0x2c0
_raw_spin_lock+0x27/0x40
? vprintk_emit+0x6d/0x2c0
vprintk_emit+0x6d/0x2c0
printk+0x4d/0x69
start_secondary+0x1c/0x100
secondary_startup_64_no_verify+0xb8/0xbb
This is avoided by moving the call to rcu_cpu_starting up near
the beginning of the start_secondary() function. Note that the
raw_smp_processor_id() is required in order to avoid calling into lockdep
before RCU has declared the CPU to be watched for readers.
Link: https://lore.kernel.org/lkml/160223032121.7002.1269740091547117869.tip-bot2@tip-bot2/
Reported-by: Qian Cai <cai@redhat.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'arch/x86/kernel/smpboot.c')
| -rw-r--r-- | arch/x86/kernel/smpboot.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index de776b2e6046..99bdcebaedfc 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -229,6 +229,7 @@ static void notrace start_secondary(void *unused) #endif cpu_init_exception_handling(); cpu_init(); + rcu_cpu_starting(raw_smp_processor_id()); x86_cpuinit.early_percpu_clock_init(); preempt_disable(); smp_callin(); |