From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 07B1EC433EF for ; Thu, 20 Jan 2022 02:08:37 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 96B136B0099; Wed, 19 Jan 2022 21:08:36 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 91AC56B009A; Wed, 19 Jan 2022 21:08:36 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7BBCD6B009B; Wed, 19 Jan 2022 21:08:36 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0043.hostedemail.com [216.40.44.43]) by kanga.kvack.org (Postfix) with ESMTP id 6F3516B0099 for ; Wed, 19 Jan 2022 21:08:36 -0500 (EST) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 3930A8123BF0 for ; Thu, 20 Jan 2022 02:08:36 +0000 (UTC) X-FDA: 79049031432.15.5A12304 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf24.hostedemail.com (Postfix) with ESMTP id B622A180007 for ; Thu, 20 Jan 2022 02:08:35 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 09A1D6157F; Thu, 20 Jan 2022 02:08:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D28DDC004E1; Thu, 20 Jan 2022 02:08:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1642644514; bh=sNUdxeGWDdjZ5sTIBjypyvsoG32kxwKMhMmDOFwDaJY=; h=Date:From:To:Subject:In-Reply-To:From; b=Gi9CHoSefOUzIvYnnAvI5Whh5jvWD76zMKXZcOKmhKHVN3g0nCLm+TtDnklN751YP j7AVZDZPTQ0SpZ/zDGtcAh1r0zdTBNEQ56aqIhDibc6i0Y6lCTetWo2BHt51vKw0e+ yEaG0A7f3mxRLw06to3PJWlOyxw937YW5T2CU1Ek= Date: Wed, 19 Jan 2022 18:08:33 -0800 From: Andrew Morton To: akpm@linux-foundation.org, alexei.starovoitov@gmail.com, andrii.nakryiko@gmail.com, andrii@kernel.org, arnaldo.melo@gmail.com, david@redhat.com, dennis.dalessandro@cornelisnetworks.com, keescook@chromium.org, laoar.shao@gmail.com, linux-mm@kvack.org, mathieu.desnoyers@efficios.com, mirq-linux@rere.qmqm.pl, mm-commits@vger.kernel.org, peterz@infradead.org, pmladek@suse.com, rostedt@goodmis.org, torvalds@linux-foundation.org, viro@zeniv.linux.org.uk, willy@infradead.org Subject: [patch 16/55] samples/bpf/test_overhead_kprobe_kern: replace bpf_probe_read_kernel with bpf_probe_read_kernel_str to get task comm Message-ID: <20220120020833.EAvz32t9w%akpm@linux-foundation.org> In-Reply-To: <20220119180714.9e187ce100e4510de3cd9f7d@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: B622A180007 X-Stat-Signature: 8yzdympa6eik77iogeko5prrb6zbgbug Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=Gi9CHoSe; dmarc=none; spf=pass (imf24.hostedemail.com: domain of akpm@linux-foundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-HE-Tag: 1642644515-132784 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Yafang Shao Subject: 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: Yafang Shao Reviewed-by: Kees Cook Acked-by: Andrii Nakryiko Reviewed-by: David Hildenbrand Cc: Mathieu Desnoyers Cc: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Michal Miroslaw Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Matthew Wilcox Cc: David Hildenbrand Cc: Al Viro Cc: Kees Cook Cc: Petr Mladek Cc: Dennis Dalessandro Signed-off-by: Andrew Morton --- samples/bpf/offwaketime_kern.c | 4 ++-- samples/bpf/test_overhead_kprobe_kern.c | 11 ++++++----- samples/bpf/test_overhead_tp_kern.c | 5 +++-- 3 files changed, 11 insertions(+), 9 deletions(-) --- a/samples/bpf/offwaketime_kern.c~samples-bpf-test_overhead_kprobe_kern-replace-bpf_probe_read_kernel-with-bpf_probe_read_kernel_str-to-get-task-comm +++ a/samples/bpf/offwaketime_kern.c @@ -113,11 +113,11 @@ static inline int update_counts(void *ct /* 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; }; --- a/samples/bpf/test_overhead_kprobe_kern.c~samples-bpf-test_overhead_kprobe_kern-replace-bpf_probe_read_kernel-with-bpf_probe_read_kernel_str-to-get-task-comm +++ a/samples/bpf/test_overhead_kprobe_kern.c @@ -6,6 +6,7 @@ */ #include #include +#include #include #include #include @@ -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; --- a/samples/bpf/test_overhead_tp_kern.c~samples-bpf-test_overhead_kprobe_kern-replace-bpf_probe_read_kernel-with-bpf_probe_read_kernel_str-to-get-task-comm +++ a/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 #include #include @@ -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") _