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Mon, 08 Nov 2021 00:39:55 -0800 (PST) Received: from localhost.localdomain ([45.63.124.202]) by smtp.gmail.com with ESMTPSA id w3sm12253206pfd.195.2021.11.08.00.39.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 08 Nov 2021 00:39:54 -0800 (PST) From: Yafang Shao To: 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, Yafang Shao , Andrii Nakryiko , Mathieu Desnoyers , Arnaldo Carvalho de Melo , Andrii Nakryiko , Michal Miroslaw , Peter Zijlstra , Steven Rostedt , Matthew Wilcox , David Hildenbrand , Al Viro , Kees Cook , Petr Mladek Subject: [PATCH 7/7] tools/testing/selftests/bpf: make it adopt to task comm size change Date: Mon, 8 Nov 2021 08:38:40 +0000 Message-Id: <20211108083840.4627-8-laoar.shao@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211108083840.4627-1-laoar.shao@gmail.com> References: <20211108083840.4627-1-laoar.shao@gmail.com> MIME-Version: 1.0 X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 3E554104F34A X-Stat-Signature: aropm7djpoh7w3gry7ntg6pscf6t1phq Authentication-Results: imf31.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=UXeJsyke; spf=pass (imf31.hostedemail.com: domain of laoar.shao@gmail.com designates 209.85.214.175 as permitted sender) smtp.mailfrom=laoar.shao@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-HE-Tag: 1636360785-42552 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: The hard-coded 16 is used in various bpf progs. These progs get task comm either via bpf_get_current_comm() or prctl() or bpf_core_read_str(), all of which can work well even if the task comm size is changed. In these BPF programs, one thing to be improved is the sched:sched_switch tracepoint args. As the tracepoint args are derived from the kernel, we'd better make it same with the kernel. So the macro TASK_COMM_LEN is converted to type enum, then all the BPF programs can get it through BTF. The BPF program which wants to use TASK_COMM_LEN should include the header vmlinux.h. Regarding the test_stacktrace_map and test_tracepoint, as the type defined in linux/bpf.h are also defined in vmlinux.h, so we don't need to include linux/bpf.h again. Signed-off-by: Yafang Shao Acked-by: Andrii Nakryiko Cc: Mathieu Desnoyers Cc: Arnaldo Carvalho de Melo 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 Acked-by: David Hildenbrand --- include/linux/sched.h | 9 +++++++-- tools/testing/selftests/bpf/progs/test_stacktrace_map.c | 6 +++--- tools/testing/selftests/bpf/progs/test_tracepoint.c | 6 +++--- 3 files changed, 13 insertions(+), 8 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index e0454e60fe8f..1c456691f890 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -274,8 +274,13 @@ struct task_group; #define get_current_state() READ_ONCE(current->__state) -/* Task command name length: */ -#define TASK_COMM_LEN 16 +/* + * Define the task command name length as enum, then it can be visible to + * BPF programs. + */ +enum { + TASK_COMM_LEN = 16, +}; extern void scheduler_tick(void); diff --git a/tools/testing/selftests/bpf/progs/test_stacktrace_map.c b/tools/testing/selftests/bpf/progs/test_stacktrace_map.c index 00ed48672620..e9b602a6dc1b 100644 --- a/tools/testing/selftests/bpf/progs/test_stacktrace_map.c +++ b/tools/testing/selftests/bpf/progs/test_stacktrace_map.c @@ -1,7 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2018 Facebook -#include +#include #include #ifndef PERF_MAX_STACK_DEPTH @@ -41,11 +41,11 @@ struct { /* 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/tools/testing/selftests/bpf/progs/test_tracepoint.c b/tools/testing/selftests/bpf/progs/test_tracepoint.c index 4b825ee122cf..f21982681e28 100644 --- a/tools/testing/selftests/bpf/progs/test_tracepoint.c +++ b/tools/testing/selftests/bpf/progs/test_tracepoint.c @@ -1,17 +1,17 @@ // SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2017 Facebook -#include +#include #include /* 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; };