From nobody Fri Dec 19 08:06:15 2025 Received: from mail-ot1-f102.google.com (mail-ot1-f102.google.com [209.85.210.102]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3E1B83B8D67 for ; Tue, 9 Dec 2025 03:14:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.102 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765250078; cv=none; b=kEUUAVb/tYs7cn7QbaHY0xyDV/8RC/KiJzeq+KH4F3Un2OgjpvA3CmXa1wXOaoK5sd5E/7b3nUWVacFN1bzqhnlKuMsoEdiJ5EDlc4nEftcXHdZG0AHi77F0qq7bLVYL2M+v4gh7sIuCYXe3URnDtRsmVUS1kSCBBdLsBGuXuZo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765250078; c=relaxed/simple; bh=ZnZgBiNuPteatBPa3l+Ueno+E6tP+ZZkudlZjhS4WIo=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=GiXr0FG7ORx3ZpcMunvPECpVhNRieNferzbsHdotF3bksWXZn9UFs7ie/X7gmDpuRyZl/MI3YsWWLXEN0pAVlmOXtZLlwSZ2aqPolZeyOZO4J58WFsh3M33us7GMby/K+1BgisfA2v7hUiAue/OnjxYvp+sWpowVNn0bLtH2Hh8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=purestorage.com; spf=fail smtp.mailfrom=purestorage.com; dkim=pass (2048-bit key) header.d=purestorage.com header.i=@purestorage.com header.b=ACE0LPCw; arc=none smtp.client-ip=209.85.210.102 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=purestorage.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=purestorage.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=purestorage.com header.i=@purestorage.com header.b="ACE0LPCw" Received: by mail-ot1-f102.google.com with SMTP id 46e09a7af769-7c72d7e6c0fso859717a34.3 for ; Mon, 08 Dec 2025 19:14:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=purestorage.com; s=google2022; t=1765250075; x=1765854875; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=AhV7UuiRfziAgkz31PmGRqa1zi8I8b6M7zmhCcc5CHM=; b=ACE0LPCwAnq1W1t8kYGAVU648U/UlIghvjZgzwDNtZfNvz7Nb6H6/aA+7Q/xYaoLJG qbgjv4/61ACAIPJrL5Ll++njwlqHyvbnfmISUlWy+SO0zL4/mZT5gXAatx0TKva1YMeO S/itCVgd37Tp6j/GpO8ilrKeBUGe6sPkdNUrf7tn9hADXcoY715RyM2BahUoyUSyXSbJ O8VmBxki/Gq+R6HLGfuOC6+pByMOjCNNL/UiLAeXDMMO2bxLr6PQH7kOReOAWBDwusp7 XHNmhWt1wM5CVpEF7jroLKTA1UPzmBzokDfL0elH6kQwYwQeGWaH+qh+yAgU6lRHBXx+ OAKA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1765250075; x=1765854875; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=AhV7UuiRfziAgkz31PmGRqa1zi8I8b6M7zmhCcc5CHM=; b=WeH0YrncWJl7eyd4fw0aH7z/Lf47LAm+jYmNRM7o21SoB4G482PZ63dFeO/7omIT1Y 8aDEH6xuqvmNYvGe9ujVdnL+d71UIn1zZrq9/VqmV987puBOCGCHYHfhd21svLNXjUAM 3+U7VqVufi6TCEAP137RkXharlPBmUTovDhaIKcl3VZbP5/NhT/vCax6hbAbeci67zRi ZwtjR4GUQyt+GpZTzAYBD3AS/6KNurjvEY2ibRa/4gEnRhcToBc9CbvllYkhuLY4jq4f LQu+moBziJCoHIlqMjiLOk/J0x3PEaVNxZ2ez5tIA7WzRSW6Ql+tBtNuDuKsyqEtTymk GYLQ== X-Forwarded-Encrypted: i=1; AJvYcCViC4KzioXoFMMiNPsbA7ODVQgIiyY03bW0xWL/iuRA3MWeYXVx3MoI6MPEA4Iz3ueWuTKSf73IfmtzBuI=@vger.kernel.org X-Gm-Message-State: AOJu0YzyIXMoNlS73i4EXtmQHd6ZUiZG9qDhVdxTdldZAyZ0iAqzKnSl O+e9MwlYbmWt0DfihQqZgn4YsYZs9Y7pCakagSGWHvxNTK207IiRodyX8yBwC+lvfxuzM8qjDuR Ynf/9pSjf13hWUPldUd43HIa/V0F2V0WtOS+ilTk1glePadgR7YJS X-Gm-Gg: ASbGnct+kv96QVtW63u69j0qyvBoskg7Wg1LqP/9b1L2rdSWgiKIAn7bOXHLUBbth2q kJKFCsElX7tI3kTdPaZoZUssF2R5PmIM8oRUdxqziO7u0zjQf/HlGOqes5D6a1k/eUeVw/DOgVB Co12QfxDGShi+D9RpWgyacq+i74u7eOdFdGF+jPje4OzlbAvoV1SwYbn1n3DnEcziy/9CSF8ylM CvD7cpOyPMf3qolKZHl+oaar9waC5tatwWJ/9f9UcUBYrG7vypW+I5uGFs9WXIDpc0mokVK+1Oh SSq2oFU5OMVZzxLbh6bnOVHUeVZcAhnPF2glDO7HlSW5Gbe1V/a+eqLtkX6pk2T1G6fy+CiyNeW MJyl2uzdvK0+12RN+d8WHWH5cymo= X-Google-Smtp-Source: AGHT+IFTQjPQj7BCoxto1UVPYn30Ma8tJts2Mm6/SWho5u13K7FUjoDUE793VaJSpxPd4WWXgIhVohrddLSt X-Received: by 2002:a05:6830:25d0:b0:7c7:59a1:48d1 with SMTP id 46e09a7af769-7cac1eddbecmr595381a34.1.1765250075291; Mon, 08 Dec 2025 19:14:35 -0800 (PST) Received: from c7-smtp-2023.dev.purestorage.com ([2620:125:9017:12:36:3:5:0]) by smtp-relay.gmail.com with ESMTPS id 46e09a7af769-7c95ac65768sm2293758a34.5.2025.12.08.19.14.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 08 Dec 2025 19:14:35 -0800 (PST) X-Relaying-Domain: purestorage.com Received: from dev-csander.dev.purestorage.com (unknown [IPv6:2620:125:9007:640:ffff::1199]) by c7-smtp-2023.dev.purestorage.com (Postfix) with ESMTP id 3D9BC3400AF; Mon, 8 Dec 2025 20:14:34 -0700 (MST) Received: by dev-csander.dev.purestorage.com (Postfix, from userid 1557716354) id 2ED0AE41461; Mon, 8 Dec 2025 20:14:34 -0700 (MST) From: Caleb Sander Mateos To: Ming Lei , Jens Axboe Cc: Caleb Sander Mateos , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] ublk: don't mutate struct bio_vec in iteration Date: Mon, 8 Dec 2025 20:14:23 -0700 Message-ID: <20251209031424.3412070-1-csander@purestorage.com> X-Mailer: git-send-email 2.45.2 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 Content-Type: text/plain; charset="utf-8" __bio_for_each_segment() uses the returned struct bio_vec's bv_len field to advance the struct bvec_iter at the end of each loop iteration. So it's incorrect to modify it during the loop. Don't assign to bv_len (or bv_offset, for that matter) in ublk_copy_user_pages(). Signed-off-by: Caleb Sander Mateos Fixes: e87d66ab27ac ("ublk: use rq_for_each_segment() for user copy") Reviewed-by: Ming Lei --- drivers/block/ublk_drv.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 2c715df63f23..1e1a167d776d 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -924,30 +924,30 @@ static size_t ublk_copy_user_pages(const struct reque= st *req, struct req_iterator iter; struct bio_vec bv; size_t done =3D 0; =20 rq_for_each_segment(bv, req, iter) { + unsigned len; void *bv_buf; size_t copied; =20 if (offset >=3D bv.bv_len) { offset -=3D bv.bv_len; continue; } =20 - bv.bv_offset +=3D offset; - bv.bv_len -=3D offset; - bv_buf =3D bvec_kmap_local(&bv); + len =3D bv.bv_len - offset; + bv_buf =3D kmap_local_page(bv.bv_page) + bv.bv_offset + offset; if (dir =3D=3D ITER_DEST) - copied =3D copy_to_iter(bv_buf, bv.bv_len, uiter); + copied =3D copy_to_iter(bv_buf, len, uiter); else - copied =3D copy_from_iter(bv_buf, bv.bv_len, uiter); + copied =3D copy_from_iter(bv_buf, len, uiter); =20 kunmap_local(bv_buf); =20 done +=3D copied; - if (copied < bv.bv_len) + if (copied < len) break; =20 offset =3D 0; } return done; --=20 2.45.2