From nobody Mon Sep 28 05:46:04 2026 Received: from smtpbgsg1.qq.com (smtpbgsg1.qq.com [54.254.200.92]) (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 E6809191F94 for ; Wed, 26 Aug 2026 06:32:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=54.254.200.92 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787725957; cv=none; b=GwFTvnPvqtMzN5dytNkciLY1eqvqOScLKy5i04KTHIw4dQo7XZfrgyFsiiUlzDpPq0FAkrbPwj43Y7r19ZPhZELD9S4Z8rUXkBxweu9cc6cF+xH+4befkkwYo13p3hlE+NeAohW/4r5nfHs3e8OVLkGjWD3cs6OczHnXFVhPxTs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787725957; c=relaxed/simple; bh=upLjFfbUbpWALtJpvj3vGLdYzZiidNDCYMOehZpnaX8=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=tGY50m7kKFGnexNqmQl3BOMaOK//hPkwG+trPCyxp4uOILHW0Jfa6wHSok60NZ9Y1tA3+fA54CoaVycu09N/9csCkJX5fpH+XD5pLAV9X/rmMcfzplVmu5iUxAuPU7Ttyj0YdgZP3197nOJs3nkkdjffn5byuKciYW8+ivu1wiU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kylinsec.com.cn; spf=pass smtp.mailfrom=kylinsec.com.cn; arc=none smtp.client-ip=54.254.200.92 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kylinsec.com.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kylinsec.com.cn X-QQ-mid: esmtpgz16t1787725891ta63e8adb X-QQ-Originating-IP: kW0zayIzP3o/qoxTIBQCQN6S1pyzy6x6ZC7xM/dLCAc= Received: from localhost.localdomain ( [111.8.45.130]) by bizesmtp.qq.com (ESMTP) with id ; Wed, 26 Aug 2026 14:31:28 +0800 (CST) X-QQ-SSF: 0000000000000000000000000000000 X-QQ-GoodBg: 0 X-BIZMAIL-ID: 17325394170361992191 EX-QQ-RecipientCnt: 11 From: Liu Dalin To: Andrew Morton , David Hildenbrand , Jason Gunthorpe Cc: John Hubbard , Peter Xu , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Liu Dalin , Deng Yingchao , Qin Yungao , Luo Qiu Subject: [PATCH] mm/gup: add NULL check for unlocked parameter in fixup_user_fault() Date: Wed, 26 Aug 2026 14:31:24 +0800 Message-ID: <6D25DBDC7BEC853D+20260826063124.3255387-1-liudalin@kylinsec.com.cn> 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-QQ-SENDSIZE: 520 Feedback-ID: esmtpgz:kylinsec.com.cn:qybglogicsvrgz:qybglogicsvrgz6b-0 X-QQ-XMAILINFO: N/5uKQClqYtPM1OK2QllPf1Za3G9snMwPFA+3bm0Rm6LdNibDniZc1NV 5FR6xe5gs/wtetbp3/uf/MxVQTQteVKy/evXkvBs8Pew0rDbGT4q7HmWgDQwaNG1ZVi4b3P wIZt1FP1OcpryZSli0gE2b4dh0wvknBPT34na/9ZXEgeJtaufPNZLV2FgDdE5h5T0t7lqTv /6yd7CuWELMi+LWjxniu0+neCxpGvnJH/8/X4M4Lv+BaXNJOKoW4Zhn4jzYRI2CZPxFbXgR dWNxr26RH+GzFXM6AtHOrRItgEPFd2wTJl+Qqun9qs2eAR2OYFuIeYgSPQbIEWKUf8Yz4Hr vaNKc41P3XfayPxfrskuqFXz1v1lkDSTD3XWcOnXwV3q6vgaVF1I5gwZ+lD6WjBwfwaOJ66 M0+xEVs0ZqRXeSxZVegisiIkk7a84pPFfUEIBkh9/ifHj3NFWLKwNMjGmnntIxksCsNPs2x Xk3Pt6P1oJ6thGOEIwO3pG8rn6M1X2OF8HpGFQNDcnIDY5eSNvTXlndI4poZ08Q8GHpj/DB ZR/4e2PwSPry0T2fW5HnziyY1igPHVMLwsGQdf3x9E7Eqi+ggEbCwv8mz+Y27ldwdoYc8xg MoYGLzVk09A4KYl7j/G4UJTaGtXKymYl1p7aiMc1CR0IaDqaDxwE6jFzY223IwXbpMm6AdJ VD6WYvIgJh5YBwWtMnpwHBgIXpzNKwNJBGODiYyaiHukg0ghL8pM3PWQXvLZ3tl4aHNTDVw 0wqDoILF6DlSzGtmSMhhMVZKeteCOUenZkmxQB2xPeU5ZEHFlX5wskOJwaddjujvud2nTru AWyiuq5jVQuUji05aTfgnHkjlTg1h0DcIERaQG3a5q4IoDFT04AlJs2z+GC1PCgKTUr0ykZ 8dc/3PyZkrALHKJDQuxQi9n/zzb9LNyARBAHCbcDUrX9tIpnm+k4FyPjMNGz4dZbecfeCqs NfrZGBzx8ucXNMplsHhmmFU1uAuiLxg97KZdLqe+xJcYZHSs+qr0W6UDi9bUaGW4VnbA42d 9kHKoyUCRH+B/x+jzFbvJfiKZWE9iMZLAkROpqNaUGWVB80nBmq33vak8/guLsc49nAL8LO 2PQRSB23xWhb0CJpVFjW18JrPZczYLq8x+27fXmTUXr6z26YP3zHiA= X-QQ-XMRINFO: NyFYKkN4Ny6FuXrnB5Ye7Aabb3ujjtK+gg== X-QQ-RECHKSPAM: 0 Content-Type: text/plain; charset="utf-8" While the current callers either pass a valid pointer or explicitly pass NULL (indicating they don't need the unlock notification), it is safer to add a defensive NULL check before dereferencing. This prevents a kernel crash if any caller passes NULL and handle_mm_fault() returns VM_FAULT_COMPLETED or VM_FAULT_RETRY. Fixes smatch warnings: - mm/gup.c:1597 fixup_user_fault() error: we previously assumed 'unlocked' = could be null (see line 1573) Fixes: 4bbd4c776a63 ("mm: move get_user_pages()-related code to separate fi= le") Assisted-by: smatch:2.0 [static analysis] Signed-off-by: Liu Dalin --- mm/gup.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 0692119b7904..d12475a7f7cc 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1594,7 +1594,8 @@ int fixup_user_fault(struct mm_struct *mm, * could tell the callers so they do not need to unlock. */ mmap_read_lock(mm); - *unlocked =3D true; + if (unlocked) + *unlocked =3D true; return 0; } =20 @@ -1608,7 +1609,8 @@ int fixup_user_fault(struct mm_struct *mm, =20 if (ret & VM_FAULT_RETRY) { mmap_read_lock(mm); - *unlocked =3D true; + if (unlocked) + *unlocked =3D true; fault_flags |=3D FAULT_FLAG_TRIED; goto retry; } --=20 2.43.0