From a115d0ed7201a5904c084ae6f07913fe2b9396a6 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Wed, 27 Feb 2019 13:22:56 -0800 Subject: bpf: set inner_map_meta->spin_lock_off correctly Commit d83525ca62cf ("bpf: introduce bpf_spin_lock") introduced bpf_spin_lock and the field spin_lock_off in kernel internal structure bpf_map has the following meaning: >=0 valid offset, <0 error For every map created, the kernel will ensure spin_lock_off has correct value. Currently, bpf_map->spin_lock_off is not copied from the inner map to the map_in_map inner_map_meta during a map_in_map type map creation, so inner_map_meta->spin_lock_off = 0. This will give verifier wrong information that inner_map has bpf_spin_lock and the bpf_spin_lock is defined at offset 0. An access to offset 0 of a value pointer will trigger the following error: bpf_spin_lock cannot be accessed directly by load/store This patch fixed the issue by copy inner map's spin_lock_off value to inner_map_meta->spin_lock_off. Fixes: d83525ca62cf ("bpf: introduce bpf_spin_lock") Signed-off-by: Yonghong Song Acked-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov --- kernel/bpf/map_in_map.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel/bpf/map_in_map.c') diff --git a/kernel/bpf/map_in_map.c b/kernel/bpf/map_in_map.c index 583346a0ab29..3dff41403583 100644 --- a/kernel/bpf/map_in_map.c +++ b/kernel/bpf/map_in_map.c @@ -58,6 +58,7 @@ struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd) inner_map_meta->value_size = inner_map->value_size; inner_map_meta->map_flags = inner_map->map_flags; inner_map_meta->max_entries = inner_map->max_entries; + inner_map_meta->spin_lock_off = inner_map->spin_lock_off; /* Misc members not needed in bpf_map_meta_equal() check. */ inner_map_meta->ops = inner_map->ops; -- cgit