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Code Issues Releases Wiki Activity

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
This commit is contained in:
Thomas Gleixner 2020-02-24 15:01:35 +01:00 committed by Alexei Starovoitov
parent dbca151cad
commit f03efe49bd
1 changed files with 1 additions and 2 deletions
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3
kernel/trace/bpf_trace.c
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@ -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();
}