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| author |   Yuntao Wang <ytcoode@gmail.com> | 2022-03-03 08:59:21 +0800 |
|---|---|---|
| committer |   Daniel Borkmann <daniel@iogearbox.net> | 2022-03-03 16:23:22 +0100 |
| commit | 41332d6e3a430adc91e0af115b4261b0d2f116ec (patch) | |
| tree | b90fb49b6b8b7bf751e72dc0114e7b010c6cb0f3 | |
| parent | Merge branch 'fixes for bpf_prog_pack' (diff) | |
| download | linux-dev-41332d6e3a430adc91e0af115b4261b0d2f116ec.tar.xz linux-dev-41332d6e3a430adc91e0af115b4261b0d2f116ec.zip | |
libbpf: Add a check to ensure that page_cnt is non-zero
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>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220303005921.53436-1-ytcoode@gmail.com
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 4 |
1 files changed, 2 insertions, 2 deletions
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); |