From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-il1-f199.google.com (mail-il1-f199.google.com [209.85.166.199]) (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 C74561F8AEE for ; Mon, 2 Dec 2024 09:01:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733130065; cv=none; b=ouC8HzPOAdC8T6dPGW73zwMMveiSoJezcsBBeJHv/sdaDFD3MOJc/blCSNMkALfJZ+16owhmdU/5NuPjUSd7I27Mrfece5u4l00ShekaTfZKGe9GEg0DVNg/4/7LI64WHFuro5JRoWYDmMHo7JA1sX5QDajbZViwRUjSjJrUHc8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733130065; c=relaxed/simple; bh=JTvtG9sx2Y0GKxJGf0sSE/cq1zn64sz//XTBIF3P5J4=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=h6lEOSjz5ieAvjMiyJUah++N38O69klJ95iZTLfpNce24YClzTHUoQmWYgdHdERBs5+HMHYCSGy1UDrFKY1j+pRNJz4oo2sC6bi41GdYg755CPuS5DSDxa+Tr71k5D4L0bvGCb6KvpIaM6rJLFEyT6Kim4t+qUqbkZIVnq2M5qA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.166.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-il1-f199.google.com with SMTP id e9e14a558f8ab-3a7bdd00353so44097315ab.1 for ; Mon, 02 Dec 2024 01:01:03 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1733130063; x=1733734863; h=to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=DNXVAwiE/8yGMiilegsGJAPl32w9GzOq4koQMweD/ic=; b=O7ZRTm3t7AiQuSjw7IJd7xPJQO9NVKDe09O7Q+lCt3I+iT1relG3HV3fknKRDDMtpQ FkXsivCtUb3sV3AoxeXrLY+csmg6tLttl+6X6alKSlMS0QLcAmGV4H0+7cauiOQRykNj Zf/aigdOoP4eqxunzM0rnWWj5AV3i6Qg7UJGU2tke8opj9EQFMWCCf/7CTO6NI+3L0xL KIiGX9a4/spHyNBdiaFVokHYiNac8/fyK6EN9cJ0h/MUXCZUQfVB34pSMKwZSCYTq0z7 DU6NuyKjLFqJZ7P/h5Nt0zZfkTAOcR6vrfYBSG4I2+fpHBo1fnGGxCXUpq4yBMeL1AsU 0X8g== X-Gm-Message-State: AOJu0YxCxsGn8erzQXcG6G4mnBVIucTvK/xsqlUfPYmt/enpDZ/BcHyQ J6Pj5FHW7i608Zb8v7nbbUhNHqVX2TrVmtPAkA/7EECo/qlQemETvCaazCdDujbV9164pUjm1T9 jGRYGQZW50YpMe9ujBgkRANpUB78VNYFrZ1VzIOpK8YzbjKTv3tKl14M= X-Google-Smtp-Source: AGHT+IGV4DBHCKg1xaNl4XqL7oZ6hLUqrELB8jAevlyV0wkN2wibakOP8TNJADJMIOPlFMLhKur8hDbXcygUUg4ZPh2+DGGZvC3D Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:1cad:b0:3a7:a69c:9692 with SMTP id e9e14a558f8ab-3a7c55e2b67mr191756815ab.21.1733130062997; Mon, 02 Dec 2024 01:01:02 -0800 (PST) Date: Mon, 02 Dec 2024 01:01:02 -0800 In-Reply-To: <67238110.050a0220.35b515.015e.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <674d774e.050a0220.48a03.0022.GAE@google.com> Subject: Re: [syzbot] Re: kernel BUG in iov_iter_revert() From: syzbot To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" For archival purposes, forwarding an incoming command email to linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com. *** Subject: Re: kernel BUG in iov_iter_revert() Author: dmantipov@yandex.ru #syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git e70140ba0d2b1a30467d4af6bcfe761327b9ec95 diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index 7ac34550c403..4404f3c6ec3e 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -95,7 +95,7 @@ static size_t netfs_load_buffer_from_ra(struct netfs_io_request *rreq, } /* - * netfs_prepare_read_iterator - Prepare the subreq iterator for I/O + * __netfs_prepare_read_iterator - Prepare the subreq iterator for I/O * @subreq: The subrequest to be set up * * Prepare the I/O iterator representing the read buffer on a subrequest for @@ -109,7 +109,7 @@ static size_t netfs_load_buffer_from_ra(struct netfs_io_request *rreq, * [!] NOTE: This must be run in the same thread as ->issue_read() was called * in as we access the readahead_control struct. */ -static ssize_t netfs_prepare_read_iterator(struct netfs_io_subrequest *subreq) +static ssize_t __netfs_prepare_read_iterator(struct netfs_io_subrequest *subreq) { struct netfs_io_request *rreq = subreq->rreq; size_t rsize = subreq->len; @@ -174,6 +174,21 @@ static ssize_t netfs_prepare_read_iterator(struct netfs_io_subrequest *subreq) return subreq->len; } +/* Wrap the above by handling possible -ENOMEM and + * marking the corresponding subrequest as cancelled. + */ +static inline ssize_t netfs_prepare_read_iterator(struct netfs_io_subrequest *subreq) +{ + struct netfs_io_request *rreq = subreq->rreq; + ssize_t slice = __netfs_prepare_read_iterator(subreq); + + if (unlikely(slice < 0)) { + atomic_dec(&rreq->nr_outstanding); + netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_cancel); + } + return slice; +} + static enum netfs_io_source netfs_cache_prepare_read(struct netfs_io_request *rreq, struct netfs_io_subrequest *subreq, loff_t i_size) @@ -285,9 +300,7 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq) } slice = netfs_prepare_read_iterator(subreq); - if (slice < 0) { - atomic_dec(&rreq->nr_outstanding); - netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_cancel); + if (unlikely(slice < 0)) { ret = slice; break; } @@ -302,6 +315,10 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq) trace_netfs_sreq(subreq, netfs_sreq_trace_submit); netfs_stat(&netfs_n_rh_zero); slice = netfs_prepare_read_iterator(subreq); + if (unlikely(slice < 0)) { + ret = slice; + break; + } __set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags); netfs_read_subreq_terminated(subreq, 0, false); goto done; @@ -310,6 +327,10 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq) if (source == NETFS_READ_FROM_CACHE) { trace_netfs_sreq(subreq, netfs_sreq_trace_submit); slice = netfs_prepare_read_iterator(subreq); + if (unlikely(slice < 0)) { + ret = slice; + break; + } netfs_read_cache_to_pagecache(rreq, subreq); goto done; } -- 2.47.1