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bpf: Fix preempt_enable_no_resched() abuse

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Unless the very next line is schedule(), or implies it, one must not use
preempt_enable_no_resched(). It can cause a preemption to go missing and
thereby cause arbitrary delays, breaking the PREEMPT=y invariant.

Cc: Roman Gushchin <guro@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Peter Zijlstra 2019-04-23 21:55:59 +02:00 committed by Alexei Starovoitov
parent 6dd7f14080
commit 0edd6b64d1
1 changed files with 1 additions and 1 deletions
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include/linux/bpf.h
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@ -510,7 +510,7 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array,
} \
_out: \
rcu_read_unlock(); \
preempt_enable_no_resched(); \
preempt_enable(); \
_ret; \
})