The per-cpu buffers contain bprintf data rather than printf arguments.
The macro name and comment were a bit confusing, this rewords them in a
clearer way.
Signed-off-by: Florent Revest <[email protected]>
---
kernel/bpf/helpers.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index ef658a9ea5c9..3a5ab614cbb0 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -692,13 +692,14 @@ static int bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype,
return -EINVAL;
}
-/* Per-cpu temp buffers which can be used by printf-like helpers for %s or %p
+/* Per-cpu temp buffers used by printf-like helpers to store the bprintf binary
+ * arguments representation.
*/
-#define MAX_PRINTF_BUF_LEN 512
+#define MAX_BPRINTF_BUF_LEN 512
/* Support executing three nested bprintf helper calls on a given CPU */
struct bpf_bprintf_buffers {
- char tmp_bufs[3][MAX_PRINTF_BUF_LEN];
+ char tmp_bufs[3][MAX_BPRINTF_BUF_LEN];
};
static DEFINE_PER_CPU(struct bpf_bprintf_buffers, bpf_bprintf_bufs);
static DEFINE_PER_CPU(int, bpf_bprintf_nest_level);
@@ -761,7 +762,7 @@ int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args,
if (num_args && try_get_fmt_tmp_buf(&tmp_buf))
return -EBUSY;
- tmp_buf_end = tmp_buf + MAX_PRINTF_BUF_LEN;
+ tmp_buf_end = tmp_buf + MAX_BPRINTF_BUF_LEN;
*bin_args = (u32 *)tmp_buf;
}
--
2.31.1.751.gd2f1c929bd-goog
The cppcheck static code analysis reported the following error:
>> helpers.c:713:43: warning: Uninitialized variable: bufs [uninitvar]
if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(bufs->tmp_bufs))) {
^
ARRAY_SIZE is a macro that expands to sizeofs, so bufs is not actually
dereferenced at runtime, and the code is actually safe. But to keep
things tidy, this patch removes the need for a call to ARRAY_SIZE by
extracting the size of the array into a macro. Cppcheck should no longer
be confused and the code ends up being a bit cleaner.
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Florent Revest <[email protected]>
---
kernel/bpf/helpers.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 3a5ab614cbb0..73443498d88f 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -698,8 +698,9 @@ static int bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype,
#define MAX_BPRINTF_BUF_LEN 512
/* Support executing three nested bprintf helper calls on a given CPU */
+#define MAX_BPRINTF_NEST_LEVEL 3
struct bpf_bprintf_buffers {
- char tmp_bufs[3][MAX_BPRINTF_BUF_LEN];
+ char tmp_bufs[MAX_BPRINTF_NEST_LEVEL][MAX_BPRINTF_BUF_LEN];
};
static DEFINE_PER_CPU(struct bpf_bprintf_buffers, bpf_bprintf_bufs);
static DEFINE_PER_CPU(int, bpf_bprintf_nest_level);
@@ -711,7 +712,7 @@ static int try_get_fmt_tmp_buf(char **tmp_buf)
preempt_disable();
nest_level = this_cpu_inc_return(bpf_bprintf_nest_level);
- if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(bufs->tmp_bufs))) {
+ if (WARN_ON_ONCE(nest_level > MAX_BPRINTF_NEST_LEVEL)) {
this_cpu_dec(bpf_bprintf_nest_level);
preempt_enable();
return -EBUSY;
--
2.31.1.751.gd2f1c929bd-goog
On Mon, May 17, 2021 at 2:29 AM Florent Revest <[email protected]> wrote:
>
> The per-cpu buffers contain bprintf data rather than printf arguments.
> The macro name and comment were a bit confusing, this rewords them in a
> clearer way.
>
> Signed-off-by: Florent Revest <[email protected]>
Acked-by: Song Liu <[email protected]>
> ---
> kernel/bpf/helpers.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
> index ef658a9ea5c9..3a5ab614cbb0 100644
> --- a/kernel/bpf/helpers.c
> +++ b/kernel/bpf/helpers.c
> @@ -692,13 +692,14 @@ static int bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype,
> return -EINVAL;
> }
>
> -/* Per-cpu temp buffers which can be used by printf-like helpers for %s or %p
> +/* Per-cpu temp buffers used by printf-like helpers to store the bprintf binary
> + * arguments representation.
> */
> -#define MAX_PRINTF_BUF_LEN 512
> +#define MAX_BPRINTF_BUF_LEN 512
>
> /* Support executing three nested bprintf helper calls on a given CPU */
> struct bpf_bprintf_buffers {
> - char tmp_bufs[3][MAX_PRINTF_BUF_LEN];
> + char tmp_bufs[3][MAX_BPRINTF_BUF_LEN];
> };
> static DEFINE_PER_CPU(struct bpf_bprintf_buffers, bpf_bprintf_bufs);
> static DEFINE_PER_CPU(int, bpf_bprintf_nest_level);
> @@ -761,7 +762,7 @@ int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args,
> if (num_args && try_get_fmt_tmp_buf(&tmp_buf))
> return -EBUSY;
>
> - tmp_buf_end = tmp_buf + MAX_PRINTF_BUF_LEN;
> + tmp_buf_end = tmp_buf + MAX_BPRINTF_BUF_LEN;
> *bin_args = (u32 *)tmp_buf;
> }
>
> --
> 2.31.1.751.gd2f1c929bd-goog
>
On Mon, May 17, 2021 at 2:29 AM Florent Revest <[email protected]> wrote:
>
> The cppcheck static code analysis reported the following error:
> >> helpers.c:713:43: warning: Uninitialized variable: bufs [uninitvar]
> if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(bufs->tmp_bufs))) {
> ^
>
> ARRAY_SIZE is a macro that expands to sizeofs, so bufs is not actually
> dereferenced at runtime, and the code is actually safe. But to keep
> things tidy, this patch removes the need for a call to ARRAY_SIZE by
> extracting the size of the array into a macro. Cppcheck should no longer
> be confused and the code ends up being a bit cleaner.
>
> Reported-by: kernel test robot <[email protected]>
> Signed-off-by: Florent Revest <[email protected]>
Acked-by: Song Liu <[email protected]>
> ---
> kernel/bpf/helpers.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
> index 3a5ab614cbb0..73443498d88f 100644
> --- a/kernel/bpf/helpers.c
> +++ b/kernel/bpf/helpers.c
> @@ -698,8 +698,9 @@ static int bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype,
> #define MAX_BPRINTF_BUF_LEN 512
>
> /* Support executing three nested bprintf helper calls on a given CPU */
> +#define MAX_BPRINTF_NEST_LEVEL 3
> struct bpf_bprintf_buffers {
> - char tmp_bufs[3][MAX_BPRINTF_BUF_LEN];
> + char tmp_bufs[MAX_BPRINTF_NEST_LEVEL][MAX_BPRINTF_BUF_LEN];
> };
> static DEFINE_PER_CPU(struct bpf_bprintf_buffers, bpf_bprintf_bufs);
> static DEFINE_PER_CPU(int, bpf_bprintf_nest_level);
> @@ -711,7 +712,7 @@ static int try_get_fmt_tmp_buf(char **tmp_buf)
>
> preempt_disable();
> nest_level = this_cpu_inc_return(bpf_bprintf_nest_level);
> - if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(bufs->tmp_bufs))) {
> + if (WARN_ON_ONCE(nest_level > MAX_BPRINTF_NEST_LEVEL)) {
> this_cpu_dec(bpf_bprintf_nest_level);
> preempt_enable();
> return -EBUSY;
> --
> 2.31.1.751.gd2f1c929bd-goog
>
Hello:
This series was applied to bpf/bpf.git (refs/heads/master):
On Mon, 17 May 2021 11:28:29 +0200 you wrote:
> The per-cpu buffers contain bprintf data rather than printf arguments.
> The macro name and comment were a bit confusing, this rewords them in a
> clearer way.
>
> Signed-off-by: Florent Revest <[email protected]>
> ---
> kernel/bpf/helpers.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
Here is the summary with links:
- [bpf,1/2] bpf: Clarify a bpf_bprintf_prepare macro
https://git.kernel.org/bpf/bpf/c/8ba1030385e3
- [bpf,2/2] bpf: Avoid using ARRAY_SIZE on an uninitialized pointer
https://git.kernel.org/bpf/bpf/c/d0c0fe10ce6d
You are awesome, thank you!
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