Commit f03efe49 authored Feb 24, 2020 by Thomas Gleixner Committed by Alexei Starovoitov Feb 24, 2020

bpf/tracing: Remove redundant preempt_disable() in __bpf_trace_run()



__bpf_trace_run() disables preemption around the BPF_PROG_RUN() invocation.

This is redundant because __bpf_trace_run() is invoked from a trace point
via __DO_TRACE() which already disables preemption _before_ invoking any of
the functions which are attached to a trace point.

Remove it and add a cant_sleep() check.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200224145642.847220186@linutronix.de

parent dbca151c

kernel/trace/bpf_trace.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -1516,10 +1516,9 @@ void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp)
		static __always_inline
		void __bpf_trace_run(struct bpf_prog prog, u64 args)
		{
		cant_sleep();
		rcu_read_lock();
		preempt_disable();
		(void) BPF_PROG_RUN(prog, args);
		preempt_enable();
		rcu_read_unlock();
		}

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