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| author | Eric Dumazet <edumazet@google.com> | 2018-02-22 19:33:24 +0300 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2018-02-22 23:27:06 +0300 |
| commit | 32fff239de37ef226d5b66329dd133f64d63b22d (patch) | |
| tree | 35ee0de8ea4ebaea6511622d12bbe177f5ed45e1 | |
| parent | 80475c48c6a8a65171e035e0915dc7996b5a0a65 (diff) | |
| download | linux-32fff239de37ef226d5b66329dd133f64d63b22d.tar.xz | |
bpf: add schedule points in percpu arrays management
syszbot managed to trigger RCU detected stalls in
bpf_array_free_percpu()
It takes time to allocate a huge percpu map, but even more time to free
it.
Since we run in process context, use cond_resched() to yield cpu if
needed.
Fixes: a10423b87a7e ("bpf: introduce BPF_MAP_TYPE_PERCPU_ARRAY map")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
| -rw-r--r-- | kernel/bpf/arraymap.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index a364c408f25a..14750e7c5ee4 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -26,8 +26,10 @@ static void bpf_array_free_percpu(struct bpf_array *array) { int i; - for (i = 0; i < array->map.max_entries; i++) + for (i = 0; i < array->map.max_entries; i++) { free_percpu(array->pptrs[i]); + cond_resched(); + } } static int bpf_array_alloc_percpu(struct bpf_array *array) @@ -43,6 +45,7 @@ static int bpf_array_alloc_percpu(struct bpf_array *array) return -ENOMEM; } array->pptrs[i] = ptr; + cond_resched(); } return 0; |