This is a note to let you know that I've just added the patch titled
bpf: Reduce smap->elem_size
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-reduce-smap-elem_size.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit dd95c48b0dd43cc09f096180ebd06fb702320d0f
Author: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
Date: Tue Dec 20 17:30:36 2022 -0800
bpf: Reduce smap->elem_size
[ Upstream commit 552d42a356ebf78df9d2f4b73e077d2459966fac ]
'struct bpf_local_storage_elem' has an unused 56 byte padding at the
end due to struct's cache-line alignment requirement. This padding
space is overlapped by storage value contents, so if we use sizeof()
to calculate the total size, we overinflate it by 56 bytes. Use
offsetof() instead to calculate more exact memory use.
Signed-off-by: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Acked-by: Yonghong Song <yhs@xxxxxx>
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Link: https://lore.kernel.org/bpf/20221221013036.3427431-1-martin.lau@xxxxxxxxx
Stable-dep-of: af253aef183a ("bpf: fix order of args in call to bpf_map_kvcalloc")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
index b1090a2b02b34..f8dd7c516e320 100644
--- a/kernel/bpf/bpf_local_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -580,8 +580,8 @@ static struct bpf_local_storage_map *__bpf_local_storage_map_alloc(union bpf_att
raw_spin_lock_init(&smap->buckets[i].lock);
}
- smap->elem_size =
- sizeof(struct bpf_local_storage_elem) + attr->value_size;
+ smap->elem_size = offsetof(struct bpf_local_storage_elem,
+ sdata.data[attr->value_size]);
return smap;
}
