samples/bpf/test_overhead_kprobe_kern: replace bpf_probe_read_kernel with bpf_probe_r...

bpf_probe_read_kernel_str() will add a nul terminator to the dst, then
we don't care about if the dst size is big enough.  This patch also
replaces the hard-coded 16 with TASK_COMM_LEN to make it grepable.

Link: https://lkml.kernel.org/r/20211120112738.45980-6-laoar.shao@gmail.com
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/samples/bpf/offwaketime_kern.c b/samples/bpf/offwaketime_kern.c
index 4866afd..eb4d947 100644 (file)
--- a/samples/bpf/offwaketime_kern.c
+++ b/samples/bpf/offwaketime_kern.c
@@ -113,11 +113,11 @@ static inline int update_counts(void *ctx, u32 pid, u64 delta)
 /* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */
 struct sched_switch_args {
        unsigned long long pad;
-       char prev_comm[16];
+       char prev_comm[TASK_COMM_LEN];
        int prev_pid;
        int prev_prio;
        long long prev_state;
-       char next_comm[16];
+       char next_comm[TASK_COMM_LEN];
        int next_pid;
        int next_prio;
 };

diff --git a/samples/bpf/test_overhead_kprobe_kern.c b/samples/bpf/test_overhead_kprobe_kern.c
index f6d593e..8fdd2c9 100644 (file)
--- a/samples/bpf/test_overhead_kprobe_kern.c
+++ b/samples/bpf/test_overhead_kprobe_kern.c
@@ -6,6 +6,7 @@
  */
 #include <linux/version.h>
 #include <linux/ptrace.h>
+#include <linux/sched.h>
 #include <uapi/linux/bpf.h>
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
@@ -22,17 +23,17 @@ int prog(struct pt_regs *ctx)
 {
        struct signal_struct *signal;
        struct task_struct *tsk;
-       char oldcomm[16] = {};
-       char newcomm[16] = {};
+       char oldcomm[TASK_COMM_LEN] = {};
+       char newcomm[TASK_COMM_LEN] = {};
        u16 oom_score_adj;
        u32 pid;
 
        tsk = (void *)PT_REGS_PARM1(ctx);
 
        pid = _(tsk->pid);
-       bpf_probe_read_kernel(oldcomm, sizeof(oldcomm), &tsk->comm);
-       bpf_probe_read_kernel(newcomm, sizeof(newcomm),
-                             (void *)PT_REGS_PARM2(ctx));
+       bpf_probe_read_kernel_str(oldcomm, sizeof(oldcomm), &tsk->comm);
+       bpf_probe_read_kernel_str(newcomm, sizeof(newcomm),
+                                 (void *)PT_REGS_PARM2(ctx));
        signal = _(tsk->signal);
        oom_score_adj = _(signal->oom_score_adj);
        return 0;

diff --git a/samples/bpf/test_overhead_tp_kern.c b/samples/bpf/test_overhead_tp_kern.c
index eaa3269..80edada 100644 (file)
--- a/samples/bpf/test_overhead_tp_kern.c
+++ b/samples/bpf/test_overhead_tp_kern.c
@@ -4,6 +4,7 @@
  * modify it under the terms of version 2 of the GNU General Public
  * License as published by the Free Software Foundation.
  */
+#include <linux/sched.h>
 #include <uapi/linux/bpf.h>
 #include <bpf/bpf_helpers.h>
 
@@ -11,8 +12,8 @@
 struct task_rename {
        __u64 pad;
        __u32 pid;
-       char oldcomm[16];
-       char newcomm[16];
+       char oldcomm[TASK_COMM_LEN];
+       char newcomm[TASK_COMM_LEN];
        __u16 oom_score_adj;
 };
 SEC("tracepoint/task/task_rename")