From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (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 865FC285CAB for ; Fri, 29 Aug 2025 09:45:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756460718; cv=none; b=Z+6tRRemI49BUfPcpU0HIYcAj9A9EfZPvzLxxvtbIXjwR0rmU+1nRqJEqc/r4+2Dn1ijnEx4aswj65j+OoEkKuvktxalcCjPP43rz+PsekhW3TDxzHxqMa/jgXaA6JOzxRVfsEphjLq3sDxajVRwCh+g3nfQQjzxM54gMx5ehR0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756460718; c=relaxed/simple; bh=90kTLjdQ5Dmkces/uCsWAArb2X21n22BDlHmzm3mHJc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=tUH1m1DVkdqVpGDuQJuq69lITM9HhsszNoAarnixaEKtiPXBX8CqEgJkMnqa5tjVGTT9mdYNbGFe507oo1slTSePb5Iy4YRpd2ArsxHzoiY75l4TyFVj1uM+FGyAvsbsl5UgMc/OAbvvanWKK6jS1PxpcvaogxovLjW3AXJ+05o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=none smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.235]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTPS id 4cCtfd2q76zYQvtx for ; Fri, 29 Aug 2025 17:45:13 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.75]) by mail.maildlp.com (Postfix) with ESMTP id E261F1A0A8B for ; Fri, 29 Aug 2025 17:45:11 +0800 (CST) Received: from [10.67.110.36] (unknown [10.67.110.36]) by APP2 (Coremail) with SMTP id Syh0CgDnD5emdrFoIQK1Ag--.15325S2; Fri, 29 Aug 2025 17:45:11 +0800 (CST) Message-ID: <3ee1aeb7-bd3a-4d6e-a446-2390de0ce561@huaweicloud.com> Date: Fri, 29 Aug 2025 17:45:10 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH -next] x86: Prevent KASAN false positive warnings in __show_regs() To: Josh Poimboeuf Cc: Andrey Ryabinin , x86@kernel.org, Thomas Gleixner , Alexander Potapenko , Andrey Konovalov , Borislav Petkov , Dave Hansen , Dmitry Vyukov , Ingo Molnar , linux-kernel@vger.kernel.org, Peter Zijlstra References: <20250818130715.2904264-1-wutengda@huaweicloud.com> <1cd29a46-3c17-42ca-af41-ed0a645b29c3@gmail.com> <2956719f-58bf-40ac-9c63-6f9a8092ae1d@huaweicloud.com> Content-Language: en-US From: Tengda Wu In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CM-TRANSID:Syh0CgDnD5emdrFoIQK1Ag--.15325S2 X-Coremail-Antispam: 1UD129KBjvdXoW7GryxGFykZF1fZryUWw45KFg_yoWfWrb_Wa yUAFWkurnIkFZ7X3Z8Kr1UJr9rWw4aqrs2qF95tF9rWry7JFWrAa18tF98Aa42qFsYyF9x uwn8ta4UK3yjvjkaLaAFLSUrUUUUjb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUbxxYFVCjjxCrM7AC8VAFwI0_Gr0_Xr1l1xkIjI8I6I8E6xAIw20E Y4v20xvaj40_Wr0E3s1l1IIY67AEw4v_Jr0_Jr4l8cAvFVAK0II2c7xJM28CjxkF64kEwV A0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVWDJVCq3wA2z4x0Y4vE2Ix0cI8IcVCY1x02 67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I 0E14v26rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40E x7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x 0Yz7v_Jr0_Gr1lF7xvr2IY64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1lc7CjxVAaw2AF wI0_Jw0_GFyl42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4 xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43 MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I 0E14v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWU JVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxUF1 v3UUUUU X-CM-SenderInfo: pzxwv0hjgdqx5xdzvxpfor3voofrz/ On 2025/8/29 3:16, Josh Poimboeuf wrote: > On Thu, Aug 28, 2025 at 08:06:17PM +0800, Tengda Wu wrote: >> +++ b/arch/x86/kernel/dumpstack.c >> @@ -189,9 +189,15 @@ static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, >> unsigned long visit_mask = 0; >> int graph_idx = 0; >> bool partial = false; >> + bool kasan_disabled = false; >> >> printk("%sCall Trace:\n", log_lvl); >> >> + if (task != current) { >> + kasan_disable_current(); >> + kasan_disabled = true; >> + } > > Looks reasonable to me, though note that some callers pass a NULL @task > to indicate 'current'. > > (No idea why, that subtlety should probably be removed...) > > So this might need to be > > if (task && task != current) { > ... > Dave mentioned that there's an object_is_on_stack available, which is essentially on_current_stack. I will try using it and send out v2. Thanks, Tengda