Merge branch 'Fix elem_size not being set for inner maps'

Browse source

Rhys Rustad-Elliott says:

====================

Commit d937bc3449 ("bpf: make uniform use of array->elem_size
everywhere in arraymap.c") changed array_map_gen_lookup to use
array->elem_size instead of round_up(map->value_size, 8) as the element
size when generating code to access a value in an array map.

array->elem_size, however, is not set by bpf_map_meta_alloc when
initializing an BPF_MAP_TYPE_ARRAY_OF_MAPS or BPF_MAP_TYPE_HASH_OF_MAPS.
This results in array_map_gen_lookup incorrectly outputting code that
always accesses index 0 in the array (as the index will be calculated
via a multiplication with the element size, which is incorrectly set to
0).

This patchset sets elem_size on the bpf_array object when allocating an
array or hash of maps to fix this and adds a selftest that accesses an
array map nested within a hash of maps at a nonzero index to prevent
regressions.

v1: https://lore.kernel.org/bpf/95b5da7c-ee52-3ecb-0a4e-f6a7a114f269@linux.dev/

Changelog:

v1 -> v2:

Address comments by Martin KaFai Lau:
- Directly use inner_array->elem_size instead of using round_up
- Move selftests to a new patch
- Use ASSERT_* macros instead of CHECK and remove duration
- Remove unnecessary usleep
- Shorten selftest name
====================

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

...

This commit is contained in:

Martin KaFai Lau 2023-06-02 16:22:13 -07:00

parent b0fd1852bc 1022b67b89

commit 23509e92cf

3 changed files with 82 additions and 2 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

8

kernel/bpf/map_in_map.c

View file

31

tools/testing/selftests/bpf/prog_tests/inner_array_lookup.c

View file

45

tools/testing/selftests/bpf/progs/inner_array_lookup.c

View file