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| author | Toshiaki Makita <toshiaki.makita1@gmail.com> | 2019-06-14 17:20:15 +0900 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2019-06-15 00:58:51 +0200 |
| commit | 86723c8640633bee4b4588d3c7784ee7a0032f65 (patch) | |
| tree | 9cb58b03a94f6b16c7ebc41ceb88f5579bea1ff8 /kernel | |
| parent | edabf4d9dd905acd60048ea1579943801e3a4876 (diff) | |
| download | lwn-86723c8640633bee4b4588d3c7784ee7a0032f65.tar.gz lwn-86723c8640633bee4b4588d3c7784ee7a0032f65.zip | |
bpf, devmap: Add missing RCU read lock on flush
.ndo_xdp_xmit() assumes it is called under RCU. For example virtio_net
uses RCU to detect it has setup the resources for tx. The assumption
accidentally broke when introducing bulk queue in devmap.
Fixes: 5d053f9da431 ("bpf: devmap prepare xdp frames for bulking")
Reported-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Toshiaki Makita <toshiaki.makita1@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/devmap.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index a126d95d12de..1defea4b2755 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -282,6 +282,7 @@ void __dev_map_flush(struct bpf_map *map) unsigned long *bitmap = this_cpu_ptr(dtab->flush_needed); u32 bit; + rcu_read_lock(); for_each_set_bit(bit, bitmap, map->max_entries) { struct bpf_dtab_netdev *dev = READ_ONCE(dtab->netdev_map[bit]); struct xdp_bulk_queue *bq; @@ -297,6 +298,7 @@ void __dev_map_flush(struct bpf_map *map) __clear_bit(bit, bitmap); } + rcu_read_unlock(); } /* rcu_read_lock (from syscall and BPF contexts) ensures that if a delete and/or @@ -389,6 +391,7 @@ static void dev_map_flush_old(struct bpf_dtab_netdev *dev) int cpu; + rcu_read_lock(); for_each_online_cpu(cpu) { bitmap = per_cpu_ptr(dev->dtab->flush_needed, cpu); __clear_bit(dev->bit, bitmap); @@ -396,6 +399,7 @@ static void dev_map_flush_old(struct bpf_dtab_netdev *dev) bq = per_cpu_ptr(dev->bulkq, cpu); bq_xmit_all(dev, bq, XDP_XMIT_FLUSH, false); } + rcu_read_unlock(); } } |