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libbpf: fix crash in XDP socket part with new larger BPF_LOG_BUF_SIZE

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In commit da11b41758 ("libbpf: teach libbpf about log_level bit 2"),
the BPF_LOG_BUF_SIZE was increased to 16M. The XDP socket part of
libbpf allocated the log_buf on the stack, but for the new 16M buffer
size this is not going to work. Change the code so it uses a 16K buffer
instead.

Fixes: da11b41758 ("libbpf: teach libbpf about log_level bit 2")
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Magnus Karlsson 2019-04-10 08:54:16 +02:00 committed by Daniel Borkmann
parent 69a0f9ecef
commit 50bd645b3a
1 changed files with 5 additions and 4 deletions
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9
tools/lib/bpf/xsk.c
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@ -259,7 +259,8 @@ out_umem_alloc:
static int xsk_load_xdp_prog(struct xsk_socket *xsk)
{
char bpf_log_buf[BPF_LOG_BUF_SIZE];
static const int log_buf_size = 16 * 1024;
char log_buf[log_buf_size];
int err, prog_fd;
/* This is the C-program:
@ -308,10 +309,10 @@ static int xsk_load_xdp_prog(struct xsk_socket *xsk)
size_t insns_cnt = sizeof(prog) / sizeof(struct bpf_insn);
prog_fd = bpf_load_program(BPF_PROG_TYPE_XDP, prog, insns_cnt,
"LGPL-2.1 or BSD-2-Clause", 0, bpf_log_buf,
BPF_LOG_BUF_SIZE);
"LGPL-2.1 or BSD-2-Clause", 0, log_buf,
log_buf_size);
if (prog_fd < 0) {
pr_warning("BPF log buffer:\n%s", bpf_log_buf);
pr_warning("BPF log buffer:\n%s", log_buf);
return prog_fd;
}