diff options
| author | Jakub Kicinski <kuba@kernel.org> | 2026-02-17 11:41:50 -0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-02-17 16:54:03 -0800 |
| commit | 3b39d73cc3379360a33eb583b17f21fe55e1288e (patch) | |
| tree | 6d531aee305e0103f1a816aa395f4b265d330c58 /tools | |
| parent | 593fffb8bcfdacc2111a9951afe1fae77988aa4a (diff) | |
bpftool: Fix truncated netlink dumps
Netlink requires that the recv buffer used during dumps is at least
min(PAGE_SIZE, 8k) (see the man page). Otherwise the messages will
get truncated. Make sure bpftool follows this requirement, avoid
missing information on systems with large pages.
Acked-by: Quentin Monnet <qmo@kernel.org>
Fixes: 7084566a236f ("tools/bpftool: Remove libbpf_internal.h usage in bpftool")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20260217194150.734701-1-kuba@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/bpf/bpftool/net.c | 5 | ||||
| -rw-r--r-- | tools/lib/bpf/netlink.c | 4 |
2 files changed, 7 insertions, 2 deletions
diff --git a/tools/bpf/bpftool/net.c b/tools/bpf/bpftool/net.c index f25d66c8395e..974189da8a91 100644 --- a/tools/bpf/bpftool/net.c +++ b/tools/bpf/bpftool/net.c @@ -156,7 +156,7 @@ static int netlink_recv(int sock, __u32 nl_pid, __u32 seq, bool multipart = true; struct nlmsgerr *err; struct nlmsghdr *nh; - char buf[4096]; + char buf[8192]; int len, ret; while (multipart) { @@ -201,6 +201,9 @@ static int netlink_recv(int sock, __u32 nl_pid, __u32 seq, return ret; } } + + if (len) + p_err("Invalid message or trailing data in Netlink response: %d bytes left", len); } ret = 0; done: diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c index c997e69d507f..c9a78fb16f11 100644 --- a/tools/lib/bpf/netlink.c +++ b/tools/lib/bpf/netlink.c @@ -143,7 +143,7 @@ static int libbpf_netlink_recv(int sock, __u32 nl_pid, int seq, struct nlmsghdr *nh; int len, ret; - ret = alloc_iov(&iov, 4096); + ret = alloc_iov(&iov, 8192); if (ret) goto done; @@ -212,6 +212,8 @@ start: } } } + if (len) + pr_warn("Invalid message or trailing data in Netlink response: %d bytes left\n", len); } ret = 0; done: |