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| author | Alexei Starovoitov <[email protected]> | 2017-03-08 04:00:13 +0000 |
|---|---|---|
| committer | David S. Miller <[email protected]> | 2017-03-09 21:27:17 +0000 |
| commit | 4fe8435909fddc97b81472026aa954e06dd192a5 (patch) | |
| tree | 31f7007c13a16573229090569e6fc3ca5c496a50 /net/unix/af_unix.c | |
| parent | bpf: fix struct htab_elem layout (diff) | |
| download | kernel-4fe8435909fddc97b81472026aa954e06dd192a5.tar.gz kernel-4fe8435909fddc97b81472026aa954e06dd192a5.zip | |
bpf: convert htab map to hlist_nulls
when all map elements are pre-allocated one cpu can delete and reuse htab_elem
while another cpu is still walking the hlist. In such case the lookup may
miss the element. Convert hlist to hlist_nulls to avoid such scenario.
When bucket lock is taken there is no need to take such precautions,
so only convert map_lookup and map_get_next to nulls.
The race window is extremely small and only reproducible with explicit
udelay() inside lookup_nulls_elem_raw()
Similar to hlist add hlist_nulls_for_each_entry_safe() and
hlist_nulls_entry_safe() helpers.
Fixes: 6c9059817432 ("bpf: pre-allocate hash map elements")
Reported-by: Jonathan Perry <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Acked-by: Daniel Borkmann <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Diffstat (limited to 'net/unix/af_unix.c')
0 files changed, 0 insertions, 0 deletions