Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.19 100/114] bpf: Fix preempt_enable_no_resched() abuse | Date | Thu, 23 May 2019 21:06:39 +0200 |
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[ Upstream commit 0edd6b64d1939e9e9168ff27947995bb7751db5d ]
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> Signed-off-by: Sasha Levin <sashal@kernel.org> --- include/linux/bpf.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 523481a3471b5..fd95f2efe5f32 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -400,7 +400,7 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, } \ _out: \ rcu_read_unlock(); \ - preempt_enable_no_resched(); \ + preempt_enable(); \ _ret; \ }) -- 2.20.1
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