On 12/7/20 6:55 PM, Andrii Nakryiko wrote:
On Sat, Dec 5, 2020 at 11:11 AM Yonghong Song <yhs@xxxxxx> wrote:
On 12/4/20 3:20 PM, Andrii Nakryiko wrote:
In case of having so many PID results that they don't fit into a singe page
(4096) bytes, bpftool will erroneously conclude that it got corrupted data due
to 4096 not being a multiple of struct pid_iter_entry, so the last entry will
be partially truncated. Fix this by sizing the buffer to fit exactly N entries
with no truncation in the middle of record.
Fixes: d53dee3fe013 ("tools/bpftool: Show info for processes holding BPF map/prog/link/btf FDs")
Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Ack with one nit below.
Acked-by: Yonghong Song <yhs@xxxxxx>
---
tools/bpf/bpftool/pids.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/bpf/bpftool/pids.c b/tools/bpf/bpftool/pids.c
index df7d8ec76036..477e55d59c34 100644
--- a/tools/bpf/bpftool/pids.c
+++ b/tools/bpf/bpftool/pids.c
@@ -89,9 +89,9 @@ libbpf_print_none(__maybe_unused enum libbpf_print_level level,
int build_obj_refs_table(struct obj_refs_table *table, enum bpf_obj_type type)
{
- char buf[4096];
- struct pid_iter_bpf *skel;
struct pid_iter_entry *e;
+ char buf[4096 / sizeof(*e) * sizeof(*e)];
+ struct pid_iter_bpf *skel;
No need to move "struct pid_iter_bpf *skel", right?
It's actually a move of `struct pid_iter_entry *e;` in from of char
buf[], to be able to use sizeof(*e) instead of sizeof(struct
pid_iter_bpf). It's just that diff tool didn't catch this properly :)
Indeed. Looking at the final code, no unnecessary code churn.
int err, ret, fd = -1, i;
libbpf_print_fn_t default_print;
