diff options
| author | Eric Dumazet <edumazet@google.com> | 2018-03-08 16:17:36 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-03-11 16:21:35 +0100 |
| commit | 2a8bc5316adc998951e8f726c31e231a6021eae2 (patch) | |
| tree | 2cd0a28879e41a86ca90701e896faa4f21224936 | |
| parent | 54c6d01b1a4fa674e70da842fef95382044dc1e4 (diff) | |
bpf: add schedule points in percpu arrays management
[ upstream commit 32fff239de37ef226d5b66329dd133f64d63b22d ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 075ddb801422..a38119e4a427 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -20,8 +20,10 @@ 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) @@ -37,6 +39,7 @@ static int bpf_array_alloc_percpu(struct bpf_array *array) return -ENOMEM; } array->pptrs[i] = ptr; + cond_resched(); } return 0; |