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 930D25437F0 for ; Tue, 8 Sep 2026 12:48:18 +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=1788871699; cv=none; b=up62vGlLt+q5Nxood74p64QiBJiFPFpgDNqs245e6U+4XXIb2PTWxYpQZrpC6xjpYVKHh1J/O3SYu4/A2swDrV54/x01E8koEjSN1QsmEHcXvMj++wpZsZTvBYkWFlwpwGAWG9nOSKAiXDDm8+9d982fLqwoSDtZxChpG7ki2OI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788871699; c=relaxed/simple; bh=N9naq3AzYuqT0gr+QkNSE0tYczHjG9fvX2R4xhc33f4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=erc66Mej2rO/ZYTg9oG5mZcFxoe49mXk1AlDolfY4iLEvTSFCEB77Npeu0QeW4IdgPLqqX/gFFJpYGxubrn2fXuL3OGkdDH1Hr2X78VHXOUIii0zAoO/yR4FHZMRzjLhdngmG2e3eyRPbNinkuyPpcowPhZ/zN+Ek046WOBghaQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 Received: by smtp.kernel.org (Postfix) with ESMTPSA id F18711F00ACF; Tue, 8 Sep 2026 12:48:17 +0000 (UTC) From: Sasha Levin To: stable@vger.kernel.org Cc: Jiri Olsa , Tao Chen , Andrii Nakryiko , Sasha Levin Subject: [PATCH 7.2.y 5/5] bpf: Disable preemption in bpf_get_stackid Date: Tue, 8 Sep 2026 08:48:13 -0400 Message-ID: <20260908124813.2161006-5-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260908124813.2161006-1-sashal@kernel.org> References: <2026090344-joystick-majestic-6d7c@gregkh> <20260908124813.2161006-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Jiri Olsa [ Upstream commit 15f1bd8574662f1b7b26aaa2e23ebf4066f0117d ] 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. Fixes: d5a3b1f69186 ("bpf: introduce BPF_MAP_TYPE_STACK_TRACE") Reported-by: Tao Chen Signed-off-by: Jiri Olsa Signed-off-by: Andrii Nakryiko Cc: stable@vger.kernel.org Link: https://lore.kernel.org/bpf/20260803210149.296496-6-jolsa@kernel.org Closes: https://lore.kernel.org/bpf/20260206090653.1336687-2-chen.dylane@linux.dev/ Signed-off-by: Sasha Levin --- 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 b85597c880d47..9b086ecbf1594 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); } -- 2.53.0