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Alexei Starovoitov authored
Though the second half of trampoline page is unused a task could be preempted in the middle of the first half of trampoline and two updates to trampoline would change the code from underneath the preempted task. Hence wait for tasks to voluntarily schedule or go to userspace. Add similar wait before freeing the trampoline. Fixes: fec56f58 ("bpf: Introduce BPF trampoline") Reported-by:
Jann Horn <jannh@google.com> Signed-off-by:
Alexei Starovoitov <ast@kernel.org> Signed-off-by:
Daniel Borkmann <daniel@iogearbox.net> Acked-by:
Paul E. McKenney <paulmck@kernel.org> Link: https://lore.kernel.org/bpf/20200121032231.3292185-1-ast@kernel.org
05d57f17