| Message ID | 1606486531-25719-4-git-send-email-hanks.chen@mediatek.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v1,1/3] irqchip/gic: enable irq target all | expand |
On 2020-11-27 14:15, Hanks Chen wrote: > Disable irq on cpu shutdown flow to ensure interrupts > did not bother this cpu after status as offline. > > To avoid suspicious RCU usage > (0)[0:swapper/0]RCU used illegally from offline CPU! ... > (0)[0:swapper/0]lockdep: [name:lockdep&]cpu_id = 0, cpu_is_offline = 1 This needs to be explained *a lot* more . My hunch is that because a CPU going offline can still receive interrupts thanks to your interrupt broadcast hack, you break some the core expectations, and RCU shouts at you. If that's indeed the case, I don't think the architecture code needs fixing (or at least, not for that). > > Signed-off-by: Hanks Chen <hanks.chen@mediatek.com> > --- > arch/arm64/kernel/smp.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c > index 82e75fc2c903..27a6553fa86f 100644 > --- a/arch/arm64/kernel/smp.c > +++ b/arch/arm64/kernel/smp.c > @@ -308,6 +308,12 @@ int __cpu_disable(void) > remove_cpu_topology(cpu); > numa_remove_cpu(cpu); > > + /* > + * we disable irq here to ensure interrupts > + * did not bother this cpu after status as offline. > + */ > + local_irq_disable(); > + > /* > * Take this CPU offline. Once we clear this, we can't return, > * and we must not schedule until we're ready to give up the cpu. Conveniently, the code that takes care of migrating the interrupts is just below this comment. Which strongly suggests that the interrupt migration is broken by your earlier patch. > @@ -842,9 +848,10 @@ void arch_irq_work_raise(void) > > static void local_cpu_stop(void) > { > + local_daif_mask(); > + > set_cpu_online(smp_processor_id(), false); > > - local_daif_mask(); > sdei_mask_local_cpu(); > cpu_park_loop(); > } What problem are you addressing here? Thanks, M.
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 82e75fc2c903..27a6553fa86f 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -308,6 +308,12 @@ int __cpu_disable(void) remove_cpu_topology(cpu); numa_remove_cpu(cpu); + /* + * we disable irq here to ensure interrupts + * did not bother this cpu after status as offline. + */ + local_irq_disable(); + /* * Take this CPU offline. Once we clear this, we can't return, * and we must not schedule until we're ready to give up the cpu. @@ -842,9 +848,10 @@ void arch_irq_work_raise(void) static void local_cpu_stop(void) { + local_daif_mask(); + set_cpu_online(smp_processor_id(), false); - local_daif_mask(); sdei_mask_local_cpu(); cpu_park_loop(); }
Disable irq on cpu shutdown flow to ensure interrupts did not bother this cpu after status as offline. To avoid suspicious RCU usage (0)[0:swapper/0]RCU used illegally from offline CPU! ... (0)[0:swapper/0]lockdep: [name:lockdep&]cpu_id = 0, cpu_is_offline = 1 Signed-off-by: Hanks Chen <hanks.chen@mediatek.com> --- arch/arm64/kernel/smp.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)