| Message ID | 20221025092843.81572-1-dev@der-flo.net (mailing list archive) |
|---|---|
| State | Rejected |
| Delegated to: | BPF |
| Headers | show |
| Series | [bpf-next] bpf: Update max_entries for array maps | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Clearly marked for bpf-next |
| netdev/fixes_present | success | Fixes tag not required for -next series |
| netdev/subject_prefix | success | Link |
| netdev/cover_letter | success | Single patches do not need cover letters |
| netdev/patch_count | success | Link |
| netdev/header_inline | success | No static functions without inline keyword in header files |
| netdev/build_32bit | success | Errors and warnings before: 5 this patch: 5 |
| netdev/cc_maintainers | success | CCed 12 of 12 maintainers |
| netdev/build_clang | success | Errors and warnings before: 5 this patch: 5 |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Signed-off-by tag matches author and committer |
| netdev/check_selftest | success | No net selftest shell script |
| netdev/verify_fixes | success | No Fixes tag |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 5 this patch: 5 |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 7 lines checked |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/source_inline | success | Was 0 now: 0 |
| bpf/vmtest-bpf-next-PR | success | PR summary |
| bpf/vmtest-bpf-next-VM_Test-4 | success | Logs for llvm-toolchain |
| bpf/vmtest-bpf-next-VM_Test-5 | success | Logs for set-matrix |
| bpf/vmtest-bpf-next-VM_Test-2 | success | Logs for build for x86_64 with gcc |
| bpf/vmtest-bpf-next-VM_Test-3 | success | Logs for build for x86_64 with llvm-16 |
| bpf/vmtest-bpf-next-VM_Test-1 | success | Logs for build for s390x with gcc |
| bpf/vmtest-bpf-next-VM_Test-15 | success | Logs for test_verifier on s390x with gcc |
| bpf/vmtest-bpf-next-VM_Test-16 | success | Logs for test_verifier on x86_64 with gcc |
| bpf/vmtest-bpf-next-VM_Test-17 | success | Logs for test_verifier on x86_64 with llvm-16 |
| bpf/vmtest-bpf-next-VM_Test-7 | success | Logs for test_maps on x86_64 with gcc |
| bpf/vmtest-bpf-next-VM_Test-8 | success | Logs for test_maps on x86_64 with llvm-16 |
| bpf/vmtest-bpf-next-VM_Test-12 | success | Logs for test_progs_no_alu32 on s390x with gcc |
| bpf/vmtest-bpf-next-VM_Test-13 | success | Logs for test_progs_no_alu32 on x86_64 with gcc |
| bpf/vmtest-bpf-next-VM_Test-14 | success | Logs for test_progs_no_alu32 on x86_64 with llvm-16 |
| bpf/vmtest-bpf-next-VM_Test-6 | success | Logs for test_maps on s390x with gcc |
| bpf/vmtest-bpf-next-VM_Test-9 | success | Logs for test_progs on s390x with gcc |
| bpf/vmtest-bpf-next-VM_Test-10 | success | Logs for test_progs on x86_64 with gcc |
| bpf/vmtest-bpf-next-VM_Test-11 | success | Logs for test_progs on x86_64 with llvm-16 |
Hi, On 10/25/2022 5:28 PM, Florian Lehner wrote: > To improve memory handling and alignment max_entries is rounded up > before using its value to allocate memory. > This can lead to a situation where more memory is allocated than usable > if max_entries is no adjusted accordingly. So this change updates > max_entries in order to make the allocated memory available. > > Signed-off-by: Florian Lehner <dev@der-flo.net> > --- > kernel/bpf/arraymap.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c > index 832b2659e96e..9411fa255ccc 100644 > --- a/kernel/bpf/arraymap.c > +++ b/kernel/bpf/arraymap.c > @@ -145,6 +145,7 @@ static struct bpf_map *array_map_alloc(union bpf_attr *attr) > /* copy mandatory map attributes */ > bpf_map_init_from_attr(&array->map, attr); > array->elem_size = elem_size; > + array->map.max_entries = max_entries; > > if (percpu && bpf_array_alloc_percpu(array)) { > bpf_map_area_free(array); The override of max_entries is unnecessary and is also wrong. bpf_array_alloc_percpu() will use array->map.max_entries to allocate per-cpu value, and if using the rounded-up max_entries, there will be memory waste because the extra allocated per-cpu values should not be accessible to bpf program or user-space program.
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index 832b2659e96e..9411fa255ccc 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -145,6 +145,7 @@ static struct bpf_map *array_map_alloc(union bpf_attr *attr) /* copy mandatory map attributes */ bpf_map_init_from_attr(&array->map, attr); array->elem_size = elem_size; + array->map.max_entries = max_entries; if (percpu && bpf_array_alloc_percpu(array)) { bpf_map_area_free(array);
To improve memory handling and alignment max_entries is rounded up before using its value to allocate memory. This can lead to a situation where more memory is allocated than usable if max_entries is no adjusted accordingly. So this change updates max_entries in order to make the allocated memory available. Signed-off-by: Florian Lehner <dev@der-flo.net> --- kernel/bpf/arraymap.c | 1 + 1 file changed, 1 insertion(+)