From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 4B333437460 for ; Wed, 29 Jul 2026 08:39:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785314381; cv=none; b=UOaNbxcW/x2ibRlRX4AiwX/kI71SV2EMIaJSHrxZhFz5GSgpFriXWMnGlXFSMgq72S+AT+zQ/ndfnBfohkyKDqu6uwDZWWQS8L41GpbO7pEdVn4MuLZSmzfaL89VSci/8nBnNWzLbz5jvBIy6ckQ2+mdPsX0kyzfNWcxzjjobl4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785314381; c=relaxed/simple; bh=O07eX2V5VxOgg/cZp4AgnCTjs98ESKSt5vB05EkKC48=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HHVjDw2UQwTOxNTjTDgXYJH59mTH+XWcozAVqJzFo8MExesxOsMPiKiATqh+TMoyRYloAF64OFrXofuitdaDMv+KcUonOmI3F4rQYLtK5/I6C6uRIZWZ9hpwL4lkwfib+85eUEh/+9Iu1uKw5zNpjIQlMgoyIEt2BWpUhgtOpE4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YKW1WgIE; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="YKW1WgIE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2190A1F00A3F; Wed, 29 Jul 2026 08:39:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785314379; bh=a24UptWvgiIeUSa0ei4gJ/Icr1UFF1mbNyQyDedmmNg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=YKW1WgIEDYmqC08DMu5HkE3MTL+eXP2zCET/4lmQrGMwfjI8tp7OuQxc71crtFBu3 RIYdHh81Gq+1JPYvBiy8VZP29emndmoacT5WfGo2UhvBY3y7D9QzLOv+gU3NzNWVks 8+VF7I+43n8+52bGRq0p4HTRZRMsK14T0IV5HP3h3T+ApAPVkkYsZVyEd5ui9lmqqt Wi6l3dy1hJ4oc6P6K2x5TA1fQjGJ5y2ZKF1bKUtNaUjwmbXj4iGgPE3matSs0nw7hR 6Dsd4izRORAigqVDg41VIPozXvUUCY3jD2Kg2shzcNK0vkEyV0kZl4r3Fff9MAXUIi uA1RLeCNFSAjQ== From: Jiri Olsa To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: bpf@vger.kernel.org, Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , Quentin Monnet , Tao Chen , STAR Labs SG , Arnaud Lecomte Subject: [PATCHv2 bpf-next 09/11] bpf: Remove trace_in argument from __bpf_get_stack Date: Wed, 29 Jul 2026 10:38:05 +0200 Message-ID: <20260729083807.1588544-10-jolsa@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260729083807.1588544-1-jolsa@kernel.org> References: <20260729083807.1588544-1-jolsa@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Now with the new callchain_* helper functions we can process trace_in case directly in bpf_get_stack_pe function and remove it from __bpf_get_stack which makes things easier for preemption fix in following change. Signed-off-by: Jiri Olsa --- kernel/bpf/stackmap.c | 46 ++++++++++++++++++++++++++++++++----------- 1 file changed, 34 insertions(+), 12 deletions(-) diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index 875f530f3597..bdf48a7ad2e8 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -783,7 +783,6 @@ static long callchain_finalize(void *buf, u32 size, u32 trace_nr, u32 elem_size, } static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, - struct perf_callchain_entry *trace_in, void *buf, u32 size, u64 flags, bool may_fault) { bool user_build_id = flags & BPF_F_USER_BUILD_ID; @@ -822,10 +821,7 @@ static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, if (may_fault) rcu_read_lock(); /* need RCU for perf's callchain below */ - if (trace_in) { - trace = trace_in; - trace->nr = min_t(u32, trace->nr, max_depth); - } else if (kernel && task) { + if (kernel && task) { trace = get_callchain_entry_for_task(task, max_depth); } else { trace = get_perf_callchain(regs, kernel, user, max_depth, @@ -856,7 +852,7 @@ static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, BPF_CALL_4(bpf_get_stack, struct pt_regs *, regs, void *, buf, u32, size, u64, flags) { - return __bpf_get_stack(regs, NULL, NULL, buf, size, flags, false /* !may_fault */); + return __bpf_get_stack(regs, NULL, buf, size, flags, false /* !may_fault */); } const struct bpf_func_proto bpf_get_stack_proto = { @@ -872,7 +868,7 @@ const struct bpf_func_proto bpf_get_stack_proto = { BPF_CALL_4(bpf_get_stack_sleepable, struct pt_regs *, regs, void *, buf, u32, size, u64, flags) { - return __bpf_get_stack(regs, NULL, NULL, buf, size, flags, true /* may_fault */); + return __bpf_get_stack(regs, NULL, buf, size, flags, true /* may_fault */); } const struct bpf_func_proto bpf_get_stack_sleepable_proto = { @@ -896,7 +892,7 @@ static long __bpf_get_task_stack(struct task_struct *task, void *buf, u32 size, regs = task_pt_regs(task); if (regs) - res = __bpf_get_stack(regs, task, NULL, buf, size, flags, may_fault); + res = __bpf_get_stack(regs, task, buf, size, flags, may_fault); put_task_stack(task); return res; @@ -936,6 +932,33 @@ const struct bpf_func_proto bpf_get_task_stack_sleepable_proto = { .arg4_type = ARG_ANYTHING, }; +static int __bpf_get_stack_pe(struct perf_callchain_entry *trace, void *buf, u32 size, + u64 flags) +{ + bool user_build_id = flags & BPF_F_USER_BUILD_ID; + u64 skip = flags & BPF_F_SKIP_FIELD_MASK; + bool user = flags & BPF_F_USER_STACK; + u32 elem_size, max_depth, nr_trace; + bool kernel = !user; + + if (kernel && user_build_id) + return -EINVAL; + + elem_size = user_build_id ? sizeof(struct bpf_stack_build_id) : sizeof(u64); + if (unlikely(size % elem_size)) + return -EINVAL; + + max_depth = stack_map_calculate_max_depth(size, elem_size, flags); + trace->nr = min_t(u32, trace->nr, max_depth); + + if (trace->nr < skip) + return -EFAULT; + + nr_trace = callchain_store(trace, buf, elem_size, flags); + return callchain_finalize(buf, size, nr_trace, elem_size, user_build_id, + user, false /* !may_fault */); +} + BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx, void *, buf, u32, size, u64, flags) { @@ -947,7 +970,7 @@ BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx, int err = -EINVAL; if (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)) - return __bpf_get_stack(regs, NULL, NULL, buf, size, flags, false /* !may_fault */); + return __bpf_get_stack(regs, NULL, buf, size, flags, false /* !may_fault */); if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | BPF_F_USER_BUILD_ID))) @@ -966,7 +989,7 @@ BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx, if (kernel) { trace->nr = nr_kernel; - err = __bpf_get_stack(regs, NULL, trace, buf, size, flags, false /* !may_fault */); + err = __bpf_get_stack_pe(trace, buf, size, flags); } else { /* user */ u64 skip = flags & BPF_F_SKIP_FIELD_MASK; @@ -974,9 +997,8 @@ BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx, skip += nr_kernel; if (skip > BPF_F_SKIP_FIELD_MASK) goto clear; - flags = (flags & ~BPF_F_SKIP_FIELD_MASK) | skip; - err = __bpf_get_stack(regs, NULL, trace, buf, size, flags, false /* !may_fault */); + err = __bpf_get_stack_pe(trace, buf, size, flags); } /* restore nr */ -- 2.54.0