From nobody Tue Sep 29 07:00:19 2026 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.2]) (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 4A9A4429010 for ; Tue, 11 Aug 2026 09:23:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.2 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786440240; cv=none; b=MTp/U/xehzgRu5dm6ySUPOTJlExRLq6ZPcVeTuiOiVuVuZYbZU4+BFHFzUV3PRm37qjbVkrWGWYeT8182to2sMJ0gdRZAuGn1NMyalOvxJE5zIUO/cCQZwHasGqhLp5R+KAk2jEC1qvM3XEFpfYEPJJOwu+WNN+IXvXFOTP6t4M= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786440240; c=relaxed/simple; bh=4iR9g3C0WeBYavM+AwtciROMCq32YmbRTUnxdvCBV4s=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=F1lZmH8UWYVL4v+8ZuoPuVWY/R18vNK5ZVJiF1zWjqFUxIKx7itNWk8mO5+w4Ng7XF+2k0ykgjrqzu/T4fS4y35oMMu/QP+xTbfy6fmPQmarrdWAL68h/QxvLeZ0jmScRTHwlJg4lZ+yKuaXOUStm+wJ7hKKbIb/N6G3JP8rFV4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=ABIUFPga; arc=none smtp.client-ip=220.197.31.2 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="ABIUFPga" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=w3 MYd2TVYjVgXHcht1S6pZlncyHsIQAl89MBKPGG9XA=; b=ABIUFPgalmmet5BOg0 6WOMthh2aBOugVzhYoQjk6qbo88Y3Y8ADSuNCeXIBVplqg8kb9O3TLQtDoCRG/jj J0vJsgJdmzbi5yp3No9foL+JqGepmPLZL3v/iXS8OOXdc1AcUb5gTSbW+r8K6l29 6cMgVxky4c1089BYrUyHxRy6k= Received: from neo-TianYi510Pro-15ICK.. (unknown []) by gzga-smtp-mtada-g0-1 (Coremail) with SMTP id _____wAXVi4O6npqFnMiBA--.20913S2; Tue, 11 Aug 2026 17:23:26 +0800 (CST) From: liuqiangneo@163.com To: jgg@ziepe.ca, leon@kernel.org, akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Qiang Liu Subject: [PATCH] lib/test_hmm: fix NULL deref and wrong direction in devmem fault debug message Date: Tue, 11 Aug 2026 17:22:55 +0800 Message-ID: <20260811092256.102101-1-liuqiangneo@163.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wAXVi4O6npqFnMiBA--.20913S2 X-Coremail-Antispam: 1Uf129KBjvdXoWrtr47GF47Xr43XF48Kw1DAwb_yoWDtFc_GF 409Fn5Wa4jyFyrurs3CwnrtrWFy3y7uayxuw1xJrZxuryYq39Iq34vqrsIqas8WrWqvFy3 Cr1DZry3Cw18tjkaLaAFLSUrUUUUjb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUvcSsGvfC2KfnxnUUI43ZEXa7IU8db1UUUUUU== X-CM-SenderInfo: 5olx1xxdqj0vrr6rljoofrz/xtbC3w-2WGp66g9FZwAA3p Content-Type: text/plain; charset="utf-8" From: Qiang Liu Move pr_debug() inside the `if (dpage)` block to avoid a NULL deref, and fix the direction label from "sys to dev" to "dev to sys" to match the device-to-system copy. Assisted-by: Qoder:Qwen-3.8-MAX-Preview Signed-off-by: Qiang Liu --- lib/test_hmm.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/lib/test_hmm.c b/lib/test_hmm.c index 6e72a0d8a53d..1dae93ab1e93 100644 --- a/lib/test_hmm.c +++ b/lib/test_hmm.c @@ -1151,10 +1151,9 @@ static vm_fault_t dmirror_devmem_fault_alloc_and_cop= y(struct migrate_vma *args, if (!dpage && !order) return VM_FAULT_OOM; =20 - pr_debug("migrating from sys to dev pfn src: 0x%lx pfn dst: 0x%lx\n", - page_to_pfn(spage), page_to_pfn(dpage)); - if (dpage) { + pr_debug("migrating from dev to sys pfn src: 0x%lx pfn dst: 0x%lx\n", + page_to_pfn(spage), page_to_pfn(dpage)); lock_page(dpage); *dst |=3D migrate_pfn(page_to_pfn(dpage)); } --=20 2.43.0 No virus found Checked by Hillstone Network AntiVirus