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 4B7433F9298 for ; Wed, 5 Aug 2026 09:30:07 +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=1785922208; cv=none; b=fyGT4EsK7YTh+ZqBZOKhC72VuacIMrNhxRlYJpum3pzg2AFDtnc1sk8RwaQVn4xUVbLO7GSql3Wkx1aMfm66NTIHjt8dUYxN/yhWoLGZqBHXtffIizhq+YWgPlERYP976yhBJjwD6IYQQoG+iuJ3NZrt26TOg4hxgKjEeB8ezJ0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785922208; c=relaxed/simple; bh=G0U7RI8OBwqh1iXbrFhU5q1brq3jtZXil8fMI93IXwk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XuklnPApdJ2ICVci8QvztrkYWNHnPsEe0DNlcymHbUu0bsNJbIZnujzjcV6K/uVpkjYjTpn+XTi+ip78+u4e9oZGeBsREAxIGN/Rb9MJmkrCQ/EDmpsosaWfwRSUAuU/fYoEr7Dd8B3dsO4Bw42a6tauo/ApEDX1EKDQOitEaew= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=odsryUlV; 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="odsryUlV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 698D91F000E9; Wed, 5 Aug 2026 09:30:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785922207; bh=8zAwsqU+MTKaK/Aw+1jq741kFRMC1sh3wwMY/1sz+pY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=odsryUlV/8TUU0t8+WNTWKTNWOkgiG/Yx5bKxxfpoPS8+Fq9LmVUcWLI+VMd5to+P 10vUpczZ7cTNhb2Ym72/OJkCdswTtg6IS7oNa8MICVezUY/yKYdD4jDPbrqCZdeQw5 vMsGSHnNLBZSYVQBYMFoGcowdds6DoM1pmn5vIfhMrnbeSaSYvOgcmuVb5mTaJyQgQ yz/yC0nl5YFHdRdSU6cNf5W1qR3QUvnWAyR+tvQvyH8JV90NtsbqRXcMptLfcwebRt eKOsBHvFlshTN7ev+SH/WzieDBQ/ESnoowQ0pjmt0bgq2htuzKmh0/AgLH4TvZCw8k UwIJd5HpyKzXA== 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: [PATCHv4 bpf-next 08/12] bpf: Remove trace_in argument from __bpf_get_stack Date: Wed, 5 Aug 2026 11:28:39 +0200 Message-ID: <20260805092843.516315-9-jolsa@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260805092843.516315-1-jolsa@kernel.org> References: <20260805092843.516315-1-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, 35 insertions(+), 15 deletions(-) diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index cdeb6c2e50da..b0e38e5b3738 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -780,7 +780,6 @@ 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; @@ -819,10 +818,7 @@ 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, @@ -853,7 +849,7 @@ 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 = { @@ -869,7 +865,7 @@ 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 = { @@ -893,7 +889,7 @@ 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; @@ -933,6 +929,32 @@ 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, trace_nr; + 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; + + trace_nr = callchain_store(trace, buf, elem_size, flags); + return callchain_finalize(buf, size, trace_nr, elem_size, flags, false /* !may_fault */); +} + BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx, void *, buf, u32, size, u64, flags) { @@ -944,7 +966,7 @@ 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))) @@ -964,7 +986,7 @@ 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; @@ -974,16 +996,14 @@ 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; - } const struct bpf_func_proto bpf_get_stack_proto_pe = { -- 2.54.0