From patchwork Fri Oct 13 05:42:19 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Artem Savkov X-Patchwork-Id: 13420147 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 124183D022 for ; Fri, 13 Oct 2023 05:42:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Uk0XNtz1" Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 601C1B8 for ; Thu, 12 Oct 2023 22:42:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1697175753; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=HvOpJVcRM5bVRhcIK2dFCcGNVXYwAYdPskD4OorCIcc=; b=Uk0XNtz10Tf9mwURlK/g9IREMr9pAFZX2cMVgkVpgmYB+8kTxqbsAKShmNezvc32gtdP8w EPufsYFbgPHi8RvHcm0mjPO/AQFxdSEj1zMjrBYDItqiqjkAbB3nmXZ+A8WqTT4XyGAakA Ipo2wTwhXZBpvwxS+yrKE8+Oy71q6p0= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-539--o11FYg9NjC8yFrdI-4SAg-1; Fri, 13 Oct 2023 01:42:30 -0400 X-MC-Unique: -o11FYg9NjC8yFrdI-4SAg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4C09485A5A8; Fri, 13 Oct 2023 05:42:29 +0000 (UTC) Received: from alecto.usersys.redhat.com (unknown [10.45.224.106]) by smtp.corp.redhat.com (Postfix) with ESMTP id 452F61C060DF; Fri, 13 Oct 2023 05:42:27 +0000 (UTC) From: Artem Savkov To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , bpf@vger.kernel.org, netdev@vger.kernel.org Cc: Steven Rostedt , Masami Hiramatsu , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Thomas Gleixner , linux-rt-users@vger.kernel.org, Jiri Olsa , Artem Savkov Subject: [PATCH bpf-next] bpf: change syscall_nr type to int in struct syscall_tp_t Date: Fri, 13 Oct 2023 07:42:19 +0200 Message-ID: <20231013054219.172920-1-asavkov@redhat.com> In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.7 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, RCVD_IN_DNSWL_BLOCKED,RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL, SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net linux-rt-devel tree contains a patch (b1773eac3f29c ("sched: Add support for lazy preemption")) that adds an extra member to struct trace_entry. This causes the offset of args field in struct trace_event_raw_sys_enter be different from the one in struct syscall_trace_enter: struct trace_event_raw_sys_enter { struct trace_entry ent; /* 0 12 */ /* XXX last struct has 3 bytes of padding */ /* XXX 4 bytes hole, try to pack */ long int id; /* 16 8 */ long unsigned int args[6]; /* 24 48 */ /* --- cacheline 1 boundary (64 bytes) was 8 bytes ago --- */ char __data[]; /* 72 0 */ /* size: 72, cachelines: 2, members: 4 */ /* sum members: 68, holes: 1, sum holes: 4 */ /* paddings: 1, sum paddings: 3 */ /* last cacheline: 8 bytes */ }; struct syscall_trace_enter { struct trace_entry ent; /* 0 12 */ /* XXX last struct has 3 bytes of padding */ int nr; /* 12 4 */ long unsigned int args[]; /* 16 0 */ /* size: 16, cachelines: 1, members: 3 */ /* paddings: 1, sum paddings: 3 */ /* last cacheline: 16 bytes */ }; This, in turn, causes perf_event_set_bpf_prog() fail while running bpf test_profiler testcase because max_ctx_offset is calculated based on the former struct, while off on the latter: 10488 if (is_tracepoint || is_syscall_tp) { 10489 int off = trace_event_get_offsets(event->tp_event); 10490 10491 if (prog->aux->max_ctx_offset > off) 10492 return -EACCES; 10493 } What bpf program is actually getting is a pointer to struct syscall_tp_t, defined in kernel/trace/trace_syscalls.c. This patch fixes the problem by aligning struct syscall_tp_t with with struct syscall_trace_(enter|exit) and changing the tests to use these structs to dereference context. Signed-off-by: Artem Savkov Acked-by: Steven Rostedt (Google) --- kernel/trace/trace_syscalls.c | 4 ++-- tools/testing/selftests/bpf/progs/profiler.inc.h | 2 +- tools/testing/selftests/bpf/progs/test_vmlinux.c | 4 ++-- 3 files changed, 5 insertions(+), 5 deletions(-) diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index de753403cdafb..9c581d6da843a 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -556,7 +556,7 @@ static int perf_call_bpf_enter(struct trace_event_call *call, struct pt_regs *re { struct syscall_tp_t { struct trace_entry ent; - unsigned long syscall_nr; + int syscall_nr; unsigned long args[SYSCALL_DEFINE_MAXARGS]; } __aligned(8) param; int i; @@ -661,7 +661,7 @@ static int perf_call_bpf_exit(struct trace_event_call *call, struct pt_regs *reg { struct syscall_tp_t { struct trace_entry ent; - unsigned long syscall_nr; + int syscall_nr; unsigned long ret; } __aligned(8) param; diff --git a/tools/testing/selftests/bpf/progs/profiler.inc.h b/tools/testing/selftests/bpf/progs/profiler.inc.h index f799d87e87002..897061930cb76 100644 --- a/tools/testing/selftests/bpf/progs/profiler.inc.h +++ b/tools/testing/selftests/bpf/progs/profiler.inc.h @@ -609,7 +609,7 @@ ssize_t BPF_KPROBE(kprobe__proc_sys_write, } SEC("tracepoint/syscalls/sys_enter_kill") -int tracepoint__syscalls__sys_enter_kill(struct trace_event_raw_sys_enter* ctx) +int tracepoint__syscalls__sys_enter_kill(struct syscall_trace_enter* ctx) { struct bpf_func_stats_ctx stats_ctx; diff --git a/tools/testing/selftests/bpf/progs/test_vmlinux.c b/tools/testing/selftests/bpf/progs/test_vmlinux.c index 4b8e37f7fd06c..78b23934d9f8f 100644 --- a/tools/testing/selftests/bpf/progs/test_vmlinux.c +++ b/tools/testing/selftests/bpf/progs/test_vmlinux.c @@ -16,12 +16,12 @@ bool kprobe_called = false; bool fentry_called = false; SEC("tp/syscalls/sys_enter_nanosleep") -int handle__tp(struct trace_event_raw_sys_enter *args) +int handle__tp(struct syscall_trace_enter *args) { struct __kernel_timespec *ts; long tv_nsec; - if (args->id != __NR_nanosleep) + if (args->nr != __NR_nanosleep) return 0; ts = (void *)args->args[0];