Commit d068144d authored by Yafang Shao's avatar Yafang Shao Committed by Linus Torvalds
Browse files

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

samples/bpf/test_overhead_kprobe_kern: replace bpf_probe_read_kernel with bpf_probe_read_kernel_str to get task comm

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: default avatarYafang Shao <laoar.shao@gmail.com>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Reviewed-by: default avatarDavid 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 95af469c

samples/bpf/offwaketime_kern.c

+2 −2
Original line number Diff line number Diff line
@@ -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;

};

samples/bpf/test_overhead_kprobe_kern.c

+6 −5
Original line number Diff line number Diff line
@@ -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>
@@ -22,16 +23,16 @@ 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),

	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);

samples/bpf/test_overhead_tp_kern.c

+3 −2
Original line number Diff line number Diff line
@@ -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")