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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB566C433EF for ; Thu, 11 Nov 2021 10:08:04 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 47E2D61107 for ; Thu, 11 Nov 2021 10:08:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 47E2D61107 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id D94856B0092; Thu, 11 Nov 2021 05:08:03 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id D1D6B6B0095; Thu, 11 Nov 2021 05:08:03 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BBE216B0096; Thu, 11 Nov 2021 05:08:03 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0039.hostedemail.com [216.40.44.39]) by kanga.kvack.org (Postfix) with ESMTP id AB3756B0092 for ; Thu, 11 Nov 2021 05:08:03 -0500 (EST) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 6B88B82E592D for ; Thu, 11 Nov 2021 10:08:03 +0000 (UTC) X-FDA: 78796223688.01.DBF580F Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by imf19.hostedemail.com (Postfix) with ESMTP id 0C5C8B0000A7 for ; Thu, 11 Nov 2021 10:07:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1636625270; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=O47h4DVVtUaEBtUgssjuQpExDB0fecfhYF5eRGFKZI0=; b=iC+vtIQijwBbOvb3EruXNpTVSKTum/xrBLOqrDFUKBfHSEUTBv73he9hsHTCC2DV5/BsWy VVkrm6zDHUHNFwnSnlZtt3OIn3pwdwzbXa2vzccCXh6TjeZxJrmC83AtJdlD9UV/dog5de 4iQbRs07X0V8V5EjR69PBWqHAJASBes= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1636625282; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=O47h4DVVtUaEBtUgssjuQpExDB0fecfhYF5eRGFKZI0=; b=Ett4AbyDpu1g2kDK7MGn26tqo43ImhsWZGqxgvOgZaiv8U5guB5+sNOOfGXsHKpAMazs/D x0/zIf05iSEj+wDbtmwvjv21RvqD7r5THvavAV1sop3ZfWexbkn9GsRjwVTKZcGQZ7lFpr 27hzWA1kHZqtYFwmYsyZ17tBTDGjFdw= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-565-CG7BUopAOze1aSls8xAiAQ-1; Thu, 11 Nov 2021 05:07:48 -0500 X-MC-Unique: CG7BUopAOze1aSls8xAiAQ-1 Received: by mail-wm1-f71.google.com with SMTP id g80-20020a1c2053000000b003331a764709so4555506wmg.2 for ; Thu, 11 Nov 2021 02:07:48 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:organization:in-reply-to :content-transfer-encoding; bh=O47h4DVVtUaEBtUgssjuQpExDB0fecfhYF5eRGFKZI0=; b=yGIGB9GzTf7Z93trtA93eIDja/X6ySdJbSv4d0wpU6FnTtLbQo9SxNmZS5wer5qUdT hvDoIKkfTUAbo2WaL6TJ75dsMezIxA7wfECW/cczuKs54i3pdKjKZXCRLtLnYj+046fN H8yunmlwet2M6MXo4QzaOrEcDI5+lL6xe7nQkXR1j8YM9o1c5e4QutgyhS+Cm5I+XBYJ jr4VM1N8lIiuGSy8Bqbv5Mjo9ax0PqD61rek4yvRVfOKK1Uz1Y0Hx6L1qlrcYvibA+hw IypdoGOFzDiNYqwvAoz9nsTJlGqU19Gr6aKLsWOg7LDjl96oxF4g08IZXf2zThZ8EyWB CFyw== X-Gm-Message-State: AOAM532dUpMpsfMLtvYUpVBixeOw98lIS7WCP31xNofkLuA7GE3Usedh baZXikybx1ZGqDNnhOSUY0h9ftpCo3kURDC/Wh5tIRlyzOF1TrMWgvuUyFcvnBzy1sPomuOSyG0 bvXuS4o0Z7DY= X-Received: by 2002:a5d:58ed:: with SMTP id f13mr7228908wrd.373.1636625267126; Thu, 11 Nov 2021 02:07:47 -0800 (PST) X-Google-Smtp-Source: ABdhPJzIYNQG8t7gWYqwpgZkkzMNqewJnW2iU/frpsF+W0jIDUpjovyfAg40kLr/ApFY0hP+csCBmg== X-Received: by 2002:a5d:58ed:: with SMTP id f13mr7228866wrd.373.1636625266915; Thu, 11 Nov 2021 02:07:46 -0800 (PST) Received: from [192.168.3.132] (p4ff23ee8.dip0.t-ipconnect.de. [79.242.62.232]) by smtp.gmail.com with ESMTPSA id g18sm2436886wrv.42.2021.11.11.02.07.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 11 Nov 2021 02:07:46 -0800 (PST) Message-ID: <8be53ae6-b3f9-f3da-afc7-23c8232a7a0a@redhat.com> Date: Thu, 11 Nov 2021 11:07:45 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: [PATCH 5/7] samples/bpf/test_overhead_kprobe_kern: make it adopt to task comm size change To: Yafang Shao , akpm@linux-foundation.org Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, oliver.sang@intel.com, lkp@intel.com, Kees Cook , Mathieu Desnoyers , Arnaldo Carvalho de Melo , Alexei Starovoitov , Andrii Nakryiko , Michal Miroslaw , Peter Zijlstra , Steven Rostedt , Matthew Wilcox , Al Viro , Petr Mladek References: <20211108083840.4627-1-laoar.shao@gmail.com> <20211108083840.4627-6-laoar.shao@gmail.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <20211108083840.4627-6-laoar.shao@gmail.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 0C5C8B0000A7 X-Stat-Signature: 4ax7wuj9jufiee9ek4kmogabajfddtm7 Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=iC+vtIQi; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Ett4AbyD; spf=none (imf19.hostedemail.com: domain of david@redhat.com has no SPF policy when checking 216.205.24.124) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-HE-Tag: 1636625273-379865 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: On 08.11.21 09:38, Yafang Shao wrote: > 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 adopt to task > comm size change. > > Signed-off-by: Yafang Shao > Reviewed-by: Kees Cook > 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 > --- > 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(-) > > diff --git a/samples/bpf/offwaketime_kern.c b/samples/bpf/offwaketime_kern.c > index 4866afd054da..eb4d94742e6b 100644 > --- 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 f6d593e47037..8fdd2c9c56b2 100644 > --- a/samples/bpf/test_overhead_kprobe_kern.c > +++ b/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)); It's a shame we have to do a manual copy here ... Changes LGTM Reviewed-by: David Hildenbrand -- Thanks, David / dhildenb