From 2581273d5e006b7bf26f15a0c1eaeefac1eae1d6 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 6 Dec 2016 17:50:30 -0500 Subject: net: Have __napi_schedule_irqoff() disable interrupts on RT A customer hit a crash where the napi sd->poll_list became corrupted. The customer had the bnx2x driver, which does a __napi_schedule_irqoff() in its interrupt handler. Unfortunately, when running with CONFIG_PREEMPT_RT_FULL, this interrupt handler is run as a thread and is preemptable. The call to ____napi_schedule() must be done with interrupts disabled to protect the per cpu softnet_data's "poll_list, which is protected by disabling interrupts (disabling preemption is enough when all interrupts are threaded and local_bh_disable() can't preempt)." As bnx2x isn't the only driver that does this, the safest thing to do is to make __napi_schedule_irqoff() call __napi_schedule() instead when CONFIG_PREEMPT_RT_FULL is enabled, which will call local_irq_save() before calling ____napi_schedule(). Cc: stable-rt@vger.kernel.org Signed-off-by: Steven Rostedt (Red Hat) Signed-off-by: Sebastian Andrzej Siewior --- net/core/dev.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net') diff --git a/net/core/dev.c b/net/core/dev.c index 319d38c89f12..15b0f54d3145 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4749,6 +4749,7 @@ void __napi_schedule(struct napi_struct *n) } EXPORT_SYMBOL(__napi_schedule); +#ifndef CONFIG_PREEMPT_RT_FULL /** * __napi_schedule_irqoff - schedule for receive * @n: entry to schedule @@ -4760,6 +4761,7 @@ void __napi_schedule_irqoff(struct napi_struct *n) ____napi_schedule(this_cpu_ptr(&softnet_data), n); } EXPORT_SYMBOL(__napi_schedule_irqoff); +#endif void __napi_complete(struct napi_struct *n) { -- cgit v1.2.1