From 932c60558109a9131e54dacfda6070147fd1cdfb Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Fri, 4 Dec 2020 15:20:01 -0800
Subject: [PATCH] tools/bpftool: Fix PID fetching with a lot of results
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@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20201204232002.3589803-1-andrii@kernel.org
---
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 df7d8ec7603616..477e55d59c3483 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;
int err, ret, fd = -1, i;
libbpf_print_fn_t default_print;
--
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