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 373DC3AA1BC; Tue, 13 Oct 2026 12:23:07 +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=1791894188; cv=none; b=KbbEz4zTv9x3Jj89e3fCS5eauwvdv9F0hX0hTnJPhmsJSAlB6CPp8pSlaXnCxOLgUjsbAuVyrUH/cZmweUd88ZJJDMGYfVtA7a3WNapp+cMjR2Gf4Uwzs4YN2AF3ARE3nSBGKN6bwaO1fUL9U7K876fofJbo586zj5Tjz/bgb2M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791894188; c=relaxed/simple; bh=NNLJ78zheIfN5QppIHTVdpb1JHg8caoyS7/v4rh3lzM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=st5qkp+rou1//LpN7fyEq3sUPA8zXwU6WV/fkyLziJ32q9QgJleD+j2gSevf6lbKK0NurVF3VePB+uMTX8vGkMcH3eHz/dMQkTlEmnqN9GPVAqUap67xuo4VVjvmqtseV74JMqwwXG8apCy25m6MlLciR+TQC+IOqZbbwraJY5o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=nKnCxb5f; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="nKnCxb5f" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 86EF91F000FF; Tue, 13 Oct 2026 12:23:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1791894187; bh=DqaoeI6an3CjmQE0jBoVnHN1fQnJnf9xVTX0In2sRE8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=nKnCxb5fxN2LnWcp90sxEQPtCOpWgiyZ8cDtbUEMwxE0/KyZYf+VrPYMeb5uzA+kX Nnq/Yf9WmZFEyv3jPW0otagadphYi4rvjQfRufc5lsgfJKfFyYANN8eQ4/GZvqNCqC 2GumMLEO4Szio1M9Wa0310LtZOhsokUg2GaCHnwM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jiri Olsa , Andrii Nakryiko , Sasha Levin Subject: [PATCH 6.18 439/621] bpf: Factor callchain_finalize function from __bpf_get_stack Date: Tue, 13 Oct 2026 13:37:14 +0200 Message-ID: <20261013112931.250391894@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261013112920.855194808@linuxfoundation.org> References: <20261013112920.855194808@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiri Olsa [ Upstream commit 014fbe5902dccdaef69114abdcdb15e3dbe55e34 ] The new callchain_finalize function calls the build-id retrieval (if needed) and zeroes the buffer. This makes things easier for preemption fix in following change. Signed-off-by: Jiri Olsa Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20260803210149.296496-8-jolsa@kernel.org Stable-dep-of: f5d242825ca4 ("bpf: Clear buf on error in __bpf_get_task_stack") Signed-off-by: Sasha Levin --- kernel/bpf/stackmap.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index 933edcbb92f56..8e4a716410494 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -644,16 +644,31 @@ static u32 callchain_store(struct perf_callchain_entry *trace, void *buf, return trace_nr; } +static long callchain_finalize(void *buf, u32 size, u32 trace_nr, u32 elem_size, + u64 flags, bool may_fault) +{ + bool user_build_id = flags & BPF_F_USER_BUILD_ID; + bool user = flags & BPF_F_USER_STACK; + u32 copy_len = trace_nr * elem_size; + + if (user_build_id) + stack_map_get_build_id_offset(buf, trace_nr, user, may_fault); + + if (size > copy_len) + memset(buf + copy_len, 0, size - copy_len); + return copy_len; +} + 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) { - u32 trace_nr, copy_len, elem_size, max_depth; bool user_build_id = flags & BPF_F_USER_BUILD_ID; bool crosstask = task && task != current; u32 skip = flags & BPF_F_SKIP_FIELD_MASK; bool user = flags & BPF_F_USER_STACK; struct perf_callchain_entry *trace; + u32 trace_nr, elem_size, max_depth; bool kernel = !user; int err = -EINVAL; @@ -703,19 +718,13 @@ static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, } trace_nr = callchain_store(trace, buf, elem_size, flags); - copy_len = trace_nr * elem_size; /* trace should not be dereferenced after this point */ if (may_fault) rcu_read_unlock(); preempt_enable(); - if (user_build_id) - stack_map_get_build_id_offset(buf, trace_nr, user, may_fault); - - if (size > copy_len) - memset(buf + copy_len, 0, size - copy_len); - return copy_len; + return callchain_finalize(buf, size, trace_nr, elem_size, flags, may_fault); err_fault: err = -EFAULT; -- 2.53.0