bpf: fix struct htab_elem layout

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when htab_elem is removed from the bucket list the htab_elem.hash_node.next
field should not be overridden too early otherwise we have a tiny race window
between lookup and delete.
The bug was discovered by manual code analysis and reproducible
only with explicit udelay() in lookup_elem_raw().

Fixes: 6c90598174 ("bpf: pre-allocate hash map elements")
Reported-by: Jonathan Perry <jonperry@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

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Alexei Starovoitov 2017-03-07 20:00:12 -08:00 • committed by David S. Miller

parent 745cb7f8a5

commit 9f691549f7

1 changed files with 20 additions and 5 deletions

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kernel/bpf/hashtab.c

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