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 5E1903B71B1 for ; Mon, 20 Jul 2026 08:55:16 +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=1784537717; cv=none; b=XZjRasKK28yYNRyLiGdOLO1QPhfOI4ToMLUvPau9fLQtygYdtk+lkz1Q1klEvl8Sx1/a2lziQINEJoWJ4V7Xx4r8M7pXhCa36KGLfCibVduOWrmUBayEtIIjWLFj3FNn6ZYIeXUGu1zrPK3+QxX7FYwSLpzhlLX21qL13ou2Hvw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784537717; c=relaxed/simple; bh=nq7rGnKX3a+oyE6ow8MKzs9oA8ssmCOoIOPI/7UJbQg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=i6QI+L1iLoHBwMjoCCPosyk0lv09Q82NcVR79HO8LxE9i+cu7HHy0HOhTkzHTk1ZGAEI3kd8EMLxN5w+RWh3kUilNXtldzKgYVehyX1tP5ODSToLCvK6XXT5WQGxbjSteYmzp71ifZg3RTn5y6NkZorLif8vh2pr5RrJUlUw6Hk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DGbwb6rb; 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="DGbwb6rb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D93A1F000E9; Mon, 20 Jul 2026 08:55:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784537716; bh=PN9kaf2Y/C+NT/RgCMBnfUxiG8getPm55G2Y8Yp4XG8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=DGbwb6rbwhlYr/A4VufetjcmR5H7litrsRaKyEdGPbC/noF6Ju/daUgTTpPfjIfJ+ k0yv1rYgZ4QkWcy1eudUE0manOedkyZHLGl/sezBvWstut1cymGqshjlxCwNCf4WAK lRVFheY88RXrjfijrSF2O2x2FnTK/hZiPUJMWmRaMHZrp+OFhfCIKSflobEKSMlXcB MJBgU45N19Wn+tIgD1asjTZRwODDrgIkbbPjTB/08niA1IdzUusyybb6rHoP9aUWuZ jyIA7mmliHwLKvkF5CLXsmlVvGdaiCGY30R8o1eYnLuqRjPhzdBsYFQzgoh7Novnuu /CsOTGG++/t3A== 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 Subject: [PATCH bpf-next 8/9] bpf: Remove trace_in argument from __bpf_get_stack Date: Mon, 20 Jul 2026 10:53:50 +0200 Message-ID: <20260720085351.655075-9-jolsa@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260720085351.655075-1-jolsa@kernel.org> References: <20260720085351.655075-1-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 | 50 +++++++++++++++++++++++++++++++------------ 1 file changed, 36 insertions(+), 14 deletions(-) diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index eea7b781300c..57cd4c33403b 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -784,7 +784,6 @@ 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; @@ -823,10 +822,7 @@ 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, @@ -857,7 +853,7 @@ 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 = { @@ -873,7 +869,7 @@ 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 = { @@ -897,7 +893,7 @@ 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; @@ -937,6 +933,33 @@ 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, size, 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) { @@ -948,7 +971,7 @@ BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx, __u64 nr_kernel; 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))) @@ -968,7 +991,7 @@ BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx, __u64 nr = trace->nr; 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); /* restore nr */ trace->nr = nr; @@ -978,14 +1001,13 @@ 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); } - return err; clear: - memset(buf, 0, size); + if (err < 0) + memset(buf, 0, size); return err; } -- 2.54.0