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 983D63F4DCA; Wed, 5 Aug 2026 09:29:38 +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=1785922179; cv=none; b=J4iQ4du7Sj2TdN5S8RmasVAhXjXpmHeOM8vD23TDL6bdqN7kAhytsGk5NJ183FqH0yAXL4XsBLYeSLCtDZLEBt8K0kD9IQ011qdhOxJxlkpuy1LaOZ+OS1Jo6j8QB06DWMiyfeDzHD8H4XOu2UxU5ZSztZmXJQvNxThDAj8EWJk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785922179; c=relaxed/simple; bh=lGP2X6dSU357nY8L8mbyIrpAFhTeWZvjNedNM0w7XUI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FuXiuSi7OyxYbvCey9uuwDe5VV7mufD5ZjVAzv5GN2f7IoyeYjb4MCZmS/IDY6+KXNNARodCxhE645Wq45C4HyBpkDwGzJKyp8IWo9RslINdgXWqC5oeFi2ecfA0GZQbKuwjlHSsVKPCmx4KJF7sgaXHMqiSyLglGuXwsHiQSIU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IFBSU7ni; 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="IFBSU7ni" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 365B51F000E9; Wed, 5 Aug 2026 09:29:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785922178; bh=Ra7HkvSPvuQGLIW1+R69jpUuCCgg35DjxnHgH0rDyjQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=IFBSU7niBMi8KoaVI3fdh5FWes8SAXshEK3xWkSFLyJJoHGZrdgU2cgCupROmIHLS q54HUhGjPlrnYjydxx7nHfwaSgbxDrj8z1e96txoivqACy+C1hEeev3HO3mdnW+LQk 89GDn1mHk4IRhYz3kQZnbwcVzvQ0HZVjzvLYTLp84y/+d/rHUYVkNdR8BrA1tguBjz WmJ0uaiGXwBcJ3KyU35qmO2w5GnjC7zcU3eYjoB3tUT+Al3PEXW4l3C6YpV9TeOFXt IiCu52VkDYW/WmOMJVIt4Pq9U+alcflq+sGNGEBtdbIZnQbuFb5913eZ2d4iQ0ro/s aq6wwuwePpMzg== From: Jiri Olsa To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: stable@vger.kernel.org, Tao Chen , bpf@vger.kernel.org, Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , Quentin Monnet , STAR Labs SG , Arnaud Lecomte Subject: [PATCHv4 bpf-next 05/12] bpf: Disable preemption in bpf_get_stackid Date: Wed, 5 Aug 2026 11:28:36 +0200 Message-ID: <20260805092843.516315-6-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 The get_perf_callchain call needs disabled preemption plus we need it disabled as long as we access its returned trace entries buffer. Note the bpf_get_stackid_pe function is executed already with preemption disabled. Cc: stable@vger.kernel.org Fixes: d5a3b1f69186 ("bpf: introduce BPF_MAP_TYPE_STACK_TRACE") Reported-by: Tao Chen Closes: https://lore.kernel.org/bpf/20260206090653.1336687-2-chen.dylane@linux.dev/ Signed-off-by: Jiri Olsa --- kernel/bpf/stackmap.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index 3ee0034daf52..5b18d728f4b8 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -632,20 +632,22 @@ BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, struct bpf_map *, map, return -EINVAL; max_depth = stack_map_calculate_max_depth(map->value_size, elem_size, flags); - trace = get_perf_callchain(regs, kernel, user, max_depth, - false, false, 0); - if (unlikely(!trace)) - /* couldn't fetch the stack trace */ - return -EFAULT; + scoped_guard(preempt) { + trace = get_perf_callchain(regs, kernel, user, max_depth, + false, false, 0); + if (unlikely(!trace)) + /* couldn't fetch the stack trace */ + return -EFAULT; - err = stackid_fastpath(&stackid, map, trace, flags); - if (err != -ENOENT) - return err; + err = stackid_fastpath(&stackid, map, trace, flags); + if (err != -ENOENT) + return err; - new_bucket = stackid_new_bucket(&stackid, map); - if (!new_bucket) - return -ENOMEM; + new_bucket = stackid_new_bucket(&stackid, map); + if (!new_bucket) + return -ENOMEM; + } return stackid_install(&stackid, map, new_bucket, flags); } -- 2.54.0