Message ID | 20210418135413.1204031-1-mpe@ellerman.id.au (mailing list archive) |
---|---|
State | Accepted |
Headers | show |
Series | powerpc/pseries: Stop calling printk in rtas_stop_self() | expand |
Context | Check | Description |
---|---|---|
snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (e4361a664ee985c1f54ddecf80b93159750d93d3) |
snowpatch_ozlabs/build-ppc64le | success | Build succeeded |
snowpatch_ozlabs/build-ppc64be | success | Build succeeded |
snowpatch_ozlabs/build-ppc64e | success | Build succeeded |
snowpatch_ozlabs/build-pmac32 | success | Build succeeded |
snowpatch_ozlabs/checkpatch | warning | total: 0 errors, 1 warnings, 0 checks, 9 lines checked |
snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
On Sun, 18 Apr 2021 23:54:13 +1000, Michael Ellerman wrote: > RCU complains about us calling printk() from an offline CPU: > > ============================= > WARNING: suspicious RCU usage > 5.12.0-rc7-02874-g7cf90e481cb8 #1 Not tainted > ----------------------------- > kernel/locking/lockdep.c:3568 RCU-list traversed in non-reader section!! > > [...] Applied to powerpc/next. [1/1] powerpc/pseries: Stop calling printk in rtas_stop_self() https://git.kernel.org/powerpc/c/ed8029d7b472369a010a1901358567ca3b6dbb0d cheers
diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c index ec478f8a98ff..48d9dfc3fad1 100644 --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c @@ -47,9 +47,6 @@ static void rtas_stop_self(void) BUG_ON(rtas_stop_self_token == RTAS_UNKNOWN_SERVICE); - printk("cpu %u (hwid %u) Ready to die...\n", - smp_processor_id(), hard_smp_processor_id()); - rtas_call_unlocked(&args, rtas_stop_self_token, 0, 1, NULL); panic("Alas, I survived.\n");
RCU complains about us calling printk() from an offline CPU: ============================= WARNING: suspicious RCU usage 5.12.0-rc7-02874-g7cf90e481cb8 #1 Not tainted ----------------------------- kernel/locking/lockdep.c:3568 RCU-list traversed in non-reader section!! other info that might help us debug this: RCU used illegally from offline CPU! rcu_scheduler_active = 2, debug_locks = 1 no locks held by swapper/0/0. stack backtrace: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.12.0-rc7-02874-g7cf90e481cb8 #1 Call Trace: dump_stack+0xec/0x144 (unreliable) lockdep_rcu_suspicious+0x124/0x144 __lock_acquire+0x1098/0x28b0 lock_acquire+0x128/0x600 _raw_spin_lock_irqsave+0x6c/0xc0 down_trylock+0x2c/0x70 __down_trylock_console_sem+0x60/0x140 vprintk_emit+0x1a8/0x4b0 vprintk_func+0xcc/0x200 printk+0x40/0x54 pseries_cpu_offline_self+0xc0/0x120 arch_cpu_idle_dead+0x54/0x70 do_idle+0x174/0x4a0 cpu_startup_entry+0x38/0x40 rest_init+0x268/0x388 start_kernel+0x748/0x790 start_here_common+0x1c/0x614 Which happens because by the time we get to rtas_stop_self() we are already offline. In addition the message can be spammy, and is not that helpful for users, so remove it. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> --- arch/powerpc/platforms/pseries/hotplug-cpu.c | 3 --- 1 file changed, 3 deletions(-)