| Message ID | 20220303005921.53436-1-ytcoode@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 41332d6e3a430adc91e0af115b4261b0d2f116ec |
| Delegated to: | BPF |
| Headers | show |
| Series | [bpf-next,v2] libbpf: Add a check to ensure that page_cnt is non-zero | expand |
| Context | Check | Description |
|---|---|---|
| bpf/vmtest-bpf-next-PR | success | PR summary |
| bpf/vmtest-bpf-next | success | VM_Test |
| 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: 0 this patch: 0 |
| netdev/cc_maintainers | success | CCed 10 of 10 maintainers |
| netdev/build_clang | success | Errors and warnings before: 0 this patch: 0 |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Signed-off-by tag matches author and committer |
| netdev/verify_fixes | success | No Fixes tag |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 0 this patch: 0 |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 16 lines checked |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/source_inline | success | Was 0 now: 0 |
Hello: This patch was applied to bpf/bpf-next.git (master) by Daniel Borkmann <daniel@iogearbox.net>: On Thu, 3 Mar 2022 08:59:21 +0800 you wrote: > The page_cnt parameter is used to specify the number of memory pages > allocated for each per-CPU buffer, it must be non-zero and a power of 2. > > Currently, the __perf_buffer__new() function attempts to validate that > the page_cnt is a power of 2 but forgets checking for the case where > page_cnt is zero, we can fix it by replacing 'page_cnt & (page_cnt - 1)' > with 'page_cnt == 0 || (page_cnt & (page_cnt - 1))'. > > [...] Here is the summary with links: - [bpf-next,v2] libbpf: Add a check to ensure that page_cnt is non-zero https://git.kernel.org/bpf/bpf-next/c/41332d6e3a43 You are awesome, thank you!
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index be6480e260c4..81bf01d67671 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -10951,7 +10951,7 @@ struct perf_buffer *perf_buffer__new_raw_v0_6_0(int map_fd, size_t page_cnt, { struct perf_buffer_params p = {}; - if (page_cnt == 0 || !attr) + if (!attr) return libbpf_err_ptr(-EINVAL); if (!OPTS_VALID(opts, perf_buffer_raw_opts)) @@ -10992,7 +10992,7 @@ static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt, __u32 map_info_len; int err, i, j, n; - if (page_cnt & (page_cnt - 1)) { + if (page_cnt == 0 || (page_cnt & (page_cnt - 1))) { pr_warn("page count should be power of two, but is %zu\n", page_cnt); return ERR_PTR(-EINVAL);
The page_cnt parameter is used to specify the number of memory pages allocated for each per-CPU buffer, it must be non-zero and a power of 2. Currently, the __perf_buffer__new() function attempts to validate that the page_cnt is a power of 2 but forgets checking for the case where page_cnt is zero, we can fix it by replacing 'page_cnt & (page_cnt - 1)' with 'page_cnt == 0 || (page_cnt & (page_cnt - 1))'. If so, we also don't need to add a check in perf_buffer__new_v0_6_0() to make sure that page_cnt is non-zero and the check for zero in perf_buffer__new_raw_v0_6_0() can also be removed. The code will be cleaner and more readable. Signed-off-by: Yuntao Wang <ytcoode@gmail.com> --- v1 -> v2: remove dependency on linux/log2.h header tools/lib/bpf/libbpf.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)