From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.4 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 12040C43215 for ; Sat, 23 Nov 2019 17:18:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EA9682071C for ; Sat, 23 Nov 2019 17:18:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726920AbfKWRSR (ORCPT ); Sat, 23 Nov 2019 12:18:17 -0500 Received: from mail-io1-f71.google.com ([209.85.166.71]:50316 "EHLO mail-io1-f71.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726705AbfKWRSQ (ORCPT ); Sat, 23 Nov 2019 12:18:16 -0500 Received: by mail-io1-f71.google.com with SMTP id t193so7424105iof.17 for ; Sat, 23 Nov 2019 09:18:16 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:in-reply-to:message-id:subject :from:to:cc; bh=r3IKtlP9avY/gx1gskcMuHnqiMKCHHlRn82dSbOu4hA=; b=ceC+5pfUY3ws4ti8hJoZwR0BfOmjAG6eE2bOgxRUOFdsTKv6BHRNYI0LKBdho97ERE 2jjsDujIRWobNwM08ZkkWKyU553yzQjg80X9Ya3L9DRmdxKxzA1/CzxjdYrcwlfGC+sV OYifdg39QXAhV1twMTiMy4XXeuE58rax4Hj42+LQXxh4lPIi/wDq9Y3PasoSSn/12Pg+ 6j/K0olhTp245OdyoNU4JV0SyAL5yQlb1FwX4Husvc4h8c1smaRskS6DYFwVmQ8tVlVd ZQx3XYOO/4iOlBPEy+ZjPjejYvvLWI1RCzcOC0i81D55c7W5OskpER1GeicUl8tEyWux ICUg== X-Gm-Message-State: APjAAAX83kf8Y6XrFLCrrUQNn6FMZAwDzlRH3wBgFbJbtpD8pY0qboxO axmizvg7wvChXFMa58jjmQ4dXmt6CZzVv5NfXzrPpEyD33n9 X-Google-Smtp-Source: APXvYqxKG6BQk5546U13VbdXiwmuIiKKVcHpO+QvqQB5cly4fHYZAEK8+MO2Fm6dOElx8oaeK3bsu08R73Qga2nwAuVaP2NI5bDM MIME-Version: 1.0 X-Received: by 2002:a6b:f703:: with SMTP id k3mr17592308iog.95.1574529495615; Sat, 23 Nov 2019 09:18:15 -0800 (PST) Date: Sat, 23 Nov 2019 09:18:15 -0800 In-Reply-To: X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <00000000000046a8b6059806b796@google.com> Subject: Re: Re: Re: possible deadlock in mon_bin_vma_fault From: syzbot To: Alan Stern Cc: arnd@arndb.de, gregkh@linuxfoundation.org, jrdr.linux@gmail.com, keescook@chromium.org, kstewart@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, stern@rowland.harvard.edu, syzkaller-bugs@googlegroups.com, tglx@linutronix.de, viro@zeniv.linux.org.uk, zaitcev@redhat.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Fri, 22 Nov 2019, syzbot wrote: >> > #syz test: linux-4.19.y f6e27dbb1afa >> "linux-4.19.y" does not look like a valid git repo address. > Let's try again. The "git tree" value in the original bug report was > "upstream", so I'll use that even though it doesn't look like a valid > git repo address either. > Alan Stern > #syz test: upstream f6e27dbb1afa "upstream" does not look like a valid git repo address. > commit 5252eb4c8297fedbf1c5f1e67da44efe00e6ef6b > Author: Pete Zaitcev > Date: Thu Nov 21 17:24:00 2019 -0600 > usb: Fix a deadlock in usbmon between mmap and read > Signed-off-by: Pete Zaitcev > Reported-by: syzbot+56f9673bb4cdcbeb0e92@syzkaller.appspotmail.com > diff --git a/drivers/usb/mon/mon_bin.c b/drivers/usb/mon/mon_bin.c > index ac2b4fcc265f..f48a23adbc35 100644 > --- a/drivers/usb/mon/mon_bin.c > +++ b/drivers/usb/mon/mon_bin.c > @@ -1039,12 +1039,18 @@ static long mon_bin_ioctl(struct file *file, > unsigned int cmd, unsigned long arg > mutex_lock(&rp->fetch_lock); > spin_lock_irqsave(&rp->b_lock, flags); > - mon_free_buff(rp->b_vec, rp->b_size/CHUNK_SIZE); > - kfree(rp->b_vec); > - rp->b_vec = vec; > - rp->b_size = size; > - rp->b_read = rp->b_in = rp->b_out = rp->b_cnt = 0; > - rp->cnt_lost = 0; > + if (rp->mmap_active) { > + mon_free_buff(vec, size/CHUNK_SIZE); > + kfree(vec); > + ret = -EBUSY; > + } else { > + mon_free_buff(rp->b_vec, rp->b_size/CHUNK_SIZE); > + kfree(rp->b_vec); > + rp->b_vec = vec; > + rp->b_size = size; > + rp->b_read = rp->b_in = rp->b_out = rp->b_cnt = 0; > + rp->cnt_lost = 0; > + } > spin_unlock_irqrestore(&rp->b_lock, flags); > mutex_unlock(&rp->fetch_lock); > } > @@ -1216,13 +1222,21 @@ mon_bin_poll(struct file *file, struct > poll_table_struct *wait) > static void mon_bin_vma_open(struct vm_area_struct *vma) > { > struct mon_reader_bin *rp = vma->vm_private_data; > + unsigned long flags; > + > + spin_lock_irqsave(&rp->b_lock, flags); > rp->mmap_active++; > + spin_unlock_irqrestore(&rp->b_lock, flags); > } > static void mon_bin_vma_close(struct vm_area_struct *vma) > { > + unsigned long flags; > + > struct mon_reader_bin *rp = vma->vm_private_data; > + spin_lock_irqsave(&rp->b_lock, flags); > rp->mmap_active--; > + spin_unlock_irqrestore(&rp->b_lock, flags); > } > /* > @@ -1234,16 +1248,12 @@ static vm_fault_t mon_bin_vma_fault(struct > vm_fault *vmf) > unsigned long offset, chunk_idx; > struct page *pageptr; > - mutex_lock(&rp->fetch_lock); > offset = vmf->pgoff << PAGE_SHIFT; > - if (offset >= rp->b_size) { > - mutex_unlock(&rp->fetch_lock); > + if (offset >= rp->b_size) > return VM_FAULT_SIGBUS; > - } > chunk_idx = offset / CHUNK_SIZE; > pageptr = rp->b_vec[chunk_idx].pg; > get_page(pageptr); > - mutex_unlock(&rp->fetch_lock); > vmf->page = pageptr; > return 0; > }