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[91.12.98.118]) by smtp.gmail.com with ESMTPSA id u13sm8658152wmq.14.2021.12.13.06.41.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 13 Dec 2021 06:41:44 -0800 (PST) Message-ID: Date: Mon, 13 Dec 2021 15:41:43 +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 -mm v2 1/3] elfcore: replace old hard-code 16 with TASK_COMM_LEN_16 Content-Language: en-US To: Yafang Shao , akpm@linux-foundation.org, rostedt@goodmis.org, keescook@chromium.org, pmladek@suse.com, arnaldo.melo@gmail.com, andrii.nakryiko@gmail.com, alexei.starovoitov@gmail.com Cc: linux-mm@kvack.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Mathieu Desnoyers , Michal Miroslaw , Peter Zijlstra , Matthew Wilcox , Al Viro References: <20211211063949.49533-1-laoar.shao@gmail.com> <20211211063949.49533-2-laoar.shao@gmail.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <20211211063949.49533-2-laoar.shao@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-perf-users@vger.kernel.org On 11.12.21 07:39, Yafang Shao wrote: > A new macro TASK_COMM_LEN_16 is introduced for the old hard-coded 16 to > make it more grepable. As explained above this marco, the difference > between TASK_COMM_LEN and TASK_COMM_LEN_16 is that TASK_COMM_LEN_16 must > be a fixed size 16 and can't be changed. > > Suggested-by: Steven Rostedt (VMware) > Signed-off-by: Yafang Shao > 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 > --- > include/linux/elfcore-compat.h | 8 ++------ > include/linux/elfcore.h | 9 ++------- > include/linux/sched.h | 5 +++++ > 3 files changed, 9 insertions(+), 13 deletions(-) > > diff --git a/include/linux/elfcore-compat.h b/include/linux/elfcore-compat.h > index 54feb64e9b5d..69fa1a728964 100644 > --- a/include/linux/elfcore-compat.h > +++ b/include/linux/elfcore-compat.h > @@ -5,6 +5,7 @@ > #include > #include > #include > +#include > > /* > * Make sure these layouts match the linux/elfcore.h native definitions. > @@ -43,12 +44,7 @@ struct compat_elf_prpsinfo > __compat_uid_t pr_uid; > __compat_gid_t pr_gid; > compat_pid_t pr_pid, pr_ppid, pr_pgrp, pr_sid; > - /* > - * The hard-coded 16 is derived from TASK_COMM_LEN, but it can't be > - * changed as it is exposed to userspace. We'd better make it hard-coded > - * here. > - */ > - char pr_fname[16]; > + char pr_fname[TASK_COMM_LEN_16]; > char pr_psargs[ELF_PRARGSZ]; > }; > > diff --git a/include/linux/elfcore.h b/include/linux/elfcore.h > index 746e081879a5..d3bb4bd3c985 100644 > --- a/include/linux/elfcore.h > +++ b/include/linux/elfcore.h > @@ -65,13 +65,8 @@ struct elf_prpsinfo > __kernel_gid_t pr_gid; > pid_t pr_pid, pr_ppid, pr_pgrp, pr_sid; > /* Lots missing */ > - /* > - * The hard-coded 16 is derived from TASK_COMM_LEN, but it can't be > - * changed as it is exposed to userspace. We'd better make it hard-coded > - * here. > - */ > - char pr_fname[16]; /* filename of executable */ > - char pr_psargs[ELF_PRARGSZ]; /* initial part of arg list */ > + char pr_fname[TASK_COMM_LEN_16]; /* filename of executable */ > + char pr_psargs[ELF_PRARGSZ]; /* initial part of arg list */ > }; > > static inline void elf_core_copy_regs(elf_gregset_t *elfregs, struct pt_regs *regs) > diff --git a/include/linux/sched.h b/include/linux/sched.h > index c79bd7ee6029..8d963a50a2a8 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -279,6 +279,11 @@ struct task_group; > * BPF programs. > */ > enum { > + /* > + * For the old hard-coded 16, which is exposed to userspace and can't > + * be changed. > + */ > + TASK_COMM_LEN_16 = 16, > TASK_COMM_LEN = 16, > }; > > Reviewed-by: David Hildenbrand -- Thanks, David / dhildenb