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bpf: Run sleepable programs with migration disabled

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In older non-RT kernels migrate_disable() was the same as preempt_disable().
Since commit 74d862b682 ("sched: Make migrate_disable/enable() independent of RT")
migrate_disable() is real and doesn't prevent sleeping.

Running sleepable programs with migration disabled allows to add support for
program stats and per-cpu maps later.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/bpf/20210210033634.62081-3-alexei.starovoitov@gmail.com
This commit is contained in:
Alexei Starovoitov
2021-02-09 19:36:27 -08:00
committed by Daniel Borkmann
parent 700d4796ef
commit 031d6e02dd
1 changed files with 2 additions and 0 deletions
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2
kernel/bpf/trampoline.c
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@@ -425,11 +425,13 @@ void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start)
void notrace __bpf_prog_enter_sleepable(void) void notrace __bpf_prog_enter_sleepable(void)
{ {
rcu_read_lock_trace(); rcu_read_lock_trace();
migrate_disable();
might_fault(); might_fault();
} }
void notrace __bpf_prog_exit_sleepable(void) void notrace __bpf_prog_exit_sleepable(void)
{ {
migrate_enable();
rcu_read_unlock_trace(); rcu_read_unlock_trace();
} }