| Message ID | 20221020160721.4030492-1-davemarchevsky@fb.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 9ef40974a82a474321a4c2dd75d395943930c638 |
| Delegated to: | BPF |
| Headers | show |
| Series | [v5,bpf-next,1/4] bpf: Allow ringbuf memory to be used as map key | expand |
On Thu, Oct 20, 2022 at 9:07 AM Dave Marchevsky <davemarchevsky@fb.com> wrote: > > This patch adds support for the following pattern: > > struct some_data *data = bpf_ringbuf_reserve(&ringbuf, sizeof(struct some_data, 0)); > if (!data) > return; > bpf_map_lookup_elem(&another_map, &data->some_field); > bpf_ringbuf_submit(data); > > Currently the verifier does not consider bpf_ringbuf_reserve's > PTR_TO_MEM | MEM_ALLOC ret type a valid key input to bpf_map_lookup_elem. > Since PTR_TO_MEM is by definition a valid region of memory, it is safe > to use it as a key for lookups. > > Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com> > Acked-by: Yonghong Song <yhs@fb.com> > --- LGTM Acked-by: Andrii Nakryiko <andrii@kernel.org> > v2->v3: lore.kernel.org/bpf/20220914123600.927632-1-davemarchevsky@fb.com > > * Add Yonghong ack, rebase > > v1->v2: lore.kernel.org/bpf/20220912101106.2765921-1-davemarchevsky@fb.com > > * Move test changes into separate patch - patch 2 in this series. > (Kumar, Yonghong). That patch's changelog enumerates specific > changes from v1 > * Remove PTR_TO_MEM addition from this patch - patch 1 (Yonghong) > * I don't have a usecase for PTR_TO_MEM w/o MEM_ALLOC > * Add "if (!data)" error check to example pattern in this patch > (Yonghong) > * Remove patch 2 from v1's series, which removed map_key_value_types > as it was more-or-less duplicate of mem_types > * Now that PTR_TO_MEM isn't added here, more differences between > map_key_value_types and mem_types, and no usecase for PTR_TO_BUF, > so drop for now. > > kernel/bpf/verifier.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c > index 6f6d2d511c06..97351ae3e7a7 100644 > --- a/kernel/bpf/verifier.c > +++ b/kernel/bpf/verifier.c > @@ -5641,6 +5641,7 @@ static const struct bpf_reg_types map_key_value_types = { > PTR_TO_PACKET_META, > PTR_TO_MAP_KEY, > PTR_TO_MAP_VALUE, > + PTR_TO_MEM | MEM_ALLOC, > }, > }; > > -- > 2.30.2 >
Hello: This series was applied to bpf/bpf-next.git (master) by Alexei Starovoitov <ast@kernel.org>: On Thu, 20 Oct 2022 09:07:18 -0700 you wrote: > This patch adds support for the following pattern: > > struct some_data *data = bpf_ringbuf_reserve(&ringbuf, sizeof(struct some_data, 0)); > if (!data) > return; > bpf_map_lookup_elem(&another_map, &data->some_field); > bpf_ringbuf_submit(data); > > [...] Here is the summary with links: - [v5,bpf-next,1/4] bpf: Allow ringbuf memory to be used as map key https://git.kernel.org/bpf/bpf-next/c/9ef40974a82a - [v5,bpf-next,2/4] bpf: Consider all mem_types compatible for map_{key,value} args https://git.kernel.org/bpf/bpf-next/c/d1673304097c - [v5,bpf-next,3/4] selftests/bpf: Add test verifying bpf_ringbuf_reserve retval use in map ops https://git.kernel.org/bpf/bpf-next/c/51ee71d38d8c - [v5,bpf-next,4/4] selftests/bpf: Add write to hashmap to array_map iter test https://git.kernel.org/bpf/bpf-next/c/8f4bc15b9ad7 You are awesome, thank you!
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 6f6d2d511c06..97351ae3e7a7 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5641,6 +5641,7 @@ static const struct bpf_reg_types map_key_value_types = { PTR_TO_PACKET_META, PTR_TO_MAP_KEY, PTR_TO_MAP_VALUE, + PTR_TO_MEM | MEM_ALLOC, }, };
This patch adds support for the following pattern: struct some_data *data = bpf_ringbuf_reserve(&ringbuf, sizeof(struct some_data, 0)); if (!data) return; bpf_map_lookup_elem(&another_map, &data->some_field); bpf_ringbuf_submit(data); Currently the verifier does not consider bpf_ringbuf_reserve's PTR_TO_MEM | MEM_ALLOC ret type a valid key input to bpf_map_lookup_elem. Since PTR_TO_MEM is by definition a valid region of memory, it is safe to use it as a key for lookups. Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com> Acked-by: Yonghong Song <yhs@fb.com> --- v2->v3: lore.kernel.org/bpf/20220914123600.927632-1-davemarchevsky@fb.com * Add Yonghong ack, rebase v1->v2: lore.kernel.org/bpf/20220912101106.2765921-1-davemarchevsky@fb.com * Move test changes into separate patch - patch 2 in this series. (Kumar, Yonghong). That patch's changelog enumerates specific changes from v1 * Remove PTR_TO_MEM addition from this patch - patch 1 (Yonghong) * I don't have a usecase for PTR_TO_MEM w/o MEM_ALLOC * Add "if (!data)" error check to example pattern in this patch (Yonghong) * Remove patch 2 from v1's series, which removed map_key_value_types as it was more-or-less duplicate of mem_types * Now that PTR_TO_MEM isn't added here, more differences between map_key_value_types and mem_types, and no usecase for PTR_TO_BUF, so drop for now. kernel/bpf/verifier.c | 1 + 1 file changed, 1 insertion(+)