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Lee" To: Daniel Borkmann , Alexei Starovoitov Cc: netdev@vger.kernel.org Subject: [PATCH v2 2/2] samples, selftests/bpf: add NULL check for ksym_search Date: Wed, 27 Mar 2019 23:45:49 +0900 Message-Id: <20190327144549.6685-2-danieltimlee@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190327144549.6685-1-danieltimlee@gmail.com> References: <20190327144549.6685-1-danieltimlee@gmail.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Since, ksym_search added with verification logic for symbols existence, it could return NULL when the kernel symbols are not loaded. This commit will add NULL check logic after ksym_search. Signed-off-by: Daniel T. Lee --- Changes in v2: - Added NULL check for selftests/bpf/prog_tests/get_stack_raw_tp.c samples/bpf/offwaketime_user.c | 5 +++++ samples/bpf/sampleip_user.c | 5 +++++ samples/bpf/trace_event_user.c | 5 +++++ tools/testing/selftests/bpf/prog_tests/get_stack_raw_tp.c | 4 ++-- 4 files changed, 17 insertions(+), 2 deletions(-) diff --git a/samples/bpf/offwaketime_user.c b/samples/bpf/offwaketime_user.c index f06063af9fcb..bb315ce1b866 100644 --- a/samples/bpf/offwaketime_user.c +++ b/samples/bpf/offwaketime_user.c @@ -28,6 +28,11 @@ static void print_ksym(__u64 addr) if (!addr) return; sym = ksym_search(addr); + if (!sym) { + printf("ksym not found. Is kallsyms loaded?\n"); + return; + } + if (PRINT_RAW_ADDR) printf("%s/%llx;", sym->name, addr); else diff --git a/samples/bpf/sampleip_user.c b/samples/bpf/sampleip_user.c index 216c7ecbbbe9..23b90a45c802 100644 --- a/samples/bpf/sampleip_user.c +++ b/samples/bpf/sampleip_user.c @@ -109,6 +109,11 @@ static void print_ip_map(int fd) for (i = 0; i < max; i++) { if (counts[i].ip > PAGE_OFFSET) { sym = ksym_search(counts[i].ip); + if (!sym) { + printf("ksym not found. Is kallsyms loaded?\n"); + continue; + } + printf("0x%-17llx %-32s %u\n", counts[i].ip, sym->name, counts[i].count); } else { diff --git a/samples/bpf/trace_event_user.c b/samples/bpf/trace_event_user.c index d08046ab81f0..d4178f60e075 100644 --- a/samples/bpf/trace_event_user.c +++ b/samples/bpf/trace_event_user.c @@ -34,6 +34,11 @@ static void print_ksym(__u64 addr) if (!addr) return; sym = ksym_search(addr); + if (!sym) { + printf("ksym not found. Is kallsyms loaded?\n"); + return; + } + printf("%s;", sym->name); if (!strcmp(sym->name, "sys_read")) sys_read_seen = true; diff --git a/tools/testing/selftests/bpf/prog_tests/get_stack_raw_tp.c b/tools/testing/selftests/bpf/prog_tests/get_stack_raw_tp.c index d7bb5beb1c57..c2a0a9d5591b 100644 --- a/tools/testing/selftests/bpf/prog_tests/get_stack_raw_tp.c +++ b/tools/testing/selftests/bpf/prog_tests/get_stack_raw_tp.c @@ -39,7 +39,7 @@ static int get_stack_print_output(void *data, int size) } else { for (i = 0; i < num_stack; i++) { ks = ksym_search(raw_data[i]); - if (strcmp(ks->name, nonjit_func) == 0) { + if (ks && (strcmp(ks->name, nonjit_func) == 0)) { found = true; break; } @@ -56,7 +56,7 @@ static int get_stack_print_output(void *data, int size) } else { for (i = 0; i < num_stack; i++) { ks = ksym_search(e->kern_stack[i]); - if (strcmp(ks->name, nonjit_func) == 0) { + if (ks && (strcmp(ks->name, nonjit_func) == 0)) { good_kern_stack = true; break; } -- 2.17.1