From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) (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 59965239E70 for ; Tue, 11 Nov 2025 14:06:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=67.231.145.42 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762869994; cv=none; b=Bsm9n6TIMBAEZuNC1h0FbqD4c513oOhHZMzCKIlFzGNqKrPkJ6iZ6VeMFPkEEP5q4ANobEWSAfaEFBLsxkK19jndjs+w9RLTimHEuBzi91za2qz4oEPLFKuJN4m6ui1C4yYzZZHjYmUelUvpo+NBl5+oI1y3NcGU9dxVPaYmASc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762869994; c=relaxed/simple; bh=+si8862ou1F9T1BAmoGHFYD+SieE5gMBf5QWZrz2WnQ=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=jg1AtgA+gSacD/rlx5KzxPSr/I9Iw7ZuXYH4ICcgmT+M50FG6qFUb1J1JESDjf8KrUo27Ozq0j9PMYQVTbrOnVKzkWuY7WfSK4HsLLp0Ayn2GUPgUuBZmw5KfMIMPGLCq3N4wjv7AUSDRUANgO9WL52D0396ASj0c3P8pC9viH4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=meta.com; spf=pass smtp.mailfrom=meta.com; dkim=pass (2048-bit key) header.d=meta.com header.i=@meta.com header.b=Fw+S+wUL; arc=none smtp.client-ip=67.231.145.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=meta.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=meta.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=meta.com header.i=@meta.com header.b="Fw+S+wUL" Received: from pps.filterd (m0148461.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 5AB7STj41282287 for ; Tue, 11 Nov 2025 06:06:32 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=meta.com; h=cc :content-transfer-encoding:content-type:date:from:message-id :mime-version:subject:to; s=s2048-2025-q2; bh=7/isxsudFFhOWwsRwQ 3DNbcI6iye8MVCV01lphqHFHg=; b=Fw+S+wULWjEyDVoJD6IqGlwAl23NbcbEif okPewDDaYvmzKVmCber5xEIcp8dr2iBa6y9R0Hzp/RUUu7EiqT37C01WO2YGe/Uj kWSJzrPow+hZeYg/tm2G1LoKk/Ij2ZvfNGK5Vd61PCbm+UgSziDfaXTn+HZ5965v Lhm6i9u4XaVqkpoKWYeU5X8vAVFw+6kIInrLTciKWEUiSjsUwonjPenPl8uCkwcN z8ycumceRlReyTun5IyuoAqQWrfdtV0SLhaYZ4kFKgEknkymOs3E8MEADGVArL6O LWCbWUijulcpsUENgCQAAFUAZmmDreuMsnTfINRs17YWTrN+wsow== Received: from mail.thefacebook.com ([163.114.134.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 4ac0sha2su-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 11 Nov 2025 06:06:32 -0800 (PST) Received: from twshared22445.03.snb1.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c08b:78::c78f) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.2.2562.20; Tue, 11 Nov 2025 14:06:31 +0000 Received: by devbig197.nha3.facebook.com (Postfix, from userid 544533) id 15F0E3A7E68B; Tue, 11 Nov 2025 06:06:22 -0800 (PST) From: Keith Busch To: , , CC: , Keith Busch , Matthew Wilcox Subject: [PATCH] block: fix merging data-less bios Date: Tue, 11 Nov 2025 06:06:20 -0800 Message-ID: <20251111140620.2606536-1-kbusch@meta.com> X-Mailer: git-send-email 2.47.3 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-FB-Internal: Safe Content-Type: text/plain X-Authority-Analysis: v=2.4 cv=Pf/yRyhd c=1 sm=1 tr=0 ts=691342e8 cx=c_pps a=CB4LiSf2rd0gKozIdrpkBw==:117 a=CB4LiSf2rd0gKozIdrpkBw==:17 a=6UeiqGixMTsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VwQbUJbxAAAA:8 a=JfrnYn6hAAAA:8 a=upPtVoU741YgZzhtDMoA:9 a=zZCYzV9kfG8A:10 a=1CNFftbPRP8L7MoqJWF3:22 X-Proofpoint-GUID: LcpbBNm1L6EOTvjrALBWqiZz4cCQShHc X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTExMDExMyBTYWx0ZWRfX8G8oeXXKiGaG lDuj0qnuLFenltcSDTuhIi2/A+sxscBcKZva+kDirGl71+MGO/wf3r9HzyPKc/d6GrNx6Maxb0b Q+sPBFxZG7pXtIduPlO9IBfDxHDxbZFk/nXfUjMgW+FsNG/yLwgqno7HHk/3WhAGR/DHhTp0+94 MuS0I2AKSAEZLW5OgYIitSmlbsruceQH16T8SuA8HoANEVWopnJ23BiVKRMse9vO6yy9F5dArne qrAiJhnqMnmLddZ1ylZcFxG3toBz7FbJGedA2Z/uJouFmbtVcrRQtUl9nygsOLz0hN+ji8DvLKJ WSZIH/zgeL5qhdt2CcIb8iM0wpyhS8pE8D+/9BgK9ATENMvkE6Er5r+eBIFnf74VH6/8tnNOnJt Yp/ZhiJV8B+P4ymVczvrDrk4Yzq6YQ== X-Proofpoint-ORIG-GUID: LcpbBNm1L6EOTvjrALBWqiZz4cCQShHc X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-11-11_02,2025-11-11_02,2025-10-01_01 From: Keith Busch The data segment gaps the block layer tracks doesn't apply to bio's that don't have data. Skip calculating this to fix a NULL pointer access. Fixes: 2f6b2565d43cdb5 ("block: accumulate memory segment gaps per bio") Reported-by: Matthew Wilcox Signed-off-by: Keith Busch --- block/blk-merge.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/block/blk-merge.c b/block/blk-merge.c index 3ca6fbf8b7870..d3115d7469df0 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -737,6 +737,9 @@ u8 bio_seg_gap(struct request_queue *q, struct bio *p= rev, struct bio *next, { struct bio_vec pb, nb; =20 + if (!bio_has_data(prev)) + return 0; + gaps_bit =3D min_not_zero(gaps_bit, prev->bi_bvec_gap_bit); gaps_bit =3D min_not_zero(gaps_bit, next->bi_bvec_gap_bit); =20 --=20 2.47.3