From patchwork Tue Oct 29 16:32:26 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 11218139 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5943E1390 for ; Tue, 29 Oct 2019 16:32:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 28F98208E3 for ; Tue, 29 Oct 2019 16:32:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="dnUlLPeH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390374AbfJ2Qck (ORCPT ); Tue, 29 Oct 2019 12:32:40 -0400 Received: from mail-wr1-f73.google.com ([209.85.221.73]:37721 "EHLO mail-wr1-f73.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390252AbfJ2Qcj (ORCPT ); Tue, 29 Oct 2019 12:32:39 -0400 Received: by mail-wr1-f73.google.com with SMTP id q14so8813799wrw.4 for ; Tue, 29 Oct 2019 09:32:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=aFBVvPMXMdVoNWS+arga+zyutc52PrhwrmcehtICP7Y=; b=dnUlLPeHrSuhFF3+r3nexRhXSUgG2QFJmbgnM7MsHtu9FFwvUjdpifIlzbNDwRGkd/ Rugpk2suP1+NWI0NcnbXkosWcp5TC1CcRvDazP+lW6hm5NaO4SXfRFuKQfst1xaVJ735 loWFY3SBTLlZeW5p5a4BNCH8n5LF1tQy9M5Dcw9+Hx9HDhgklnBWRMOaVr3t+JbGQwPk o6f2umBa8YgNSH/0EA9o69e8rdGo1yiXatKJ1mHoKWzbMUsqFfKYyPCdlgB1rnZCCvbE ikFEJ8JrBVmn8KZDM/0CUXuDXrNd2ZFJCWCzeVgBfFhqtnbvvxAlQICeYgavC606yNrC 8ECg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=aFBVvPMXMdVoNWS+arga+zyutc52PrhwrmcehtICP7Y=; b=s8gypUmysc8DAMt4VWTU/ASjq4MHBo7mp5uB9PF+fYwmouOvmQibdzvro2xMXcbfHE 2aUQb54Qo5U1U2aNdj3XM9FpRopDlo+/pJhgEcZr5XtElNXPXfU/RH/oK08g7kg+Do9w Y7jfSxXMFm8sk2qer1+hziplfCbCq01TYzNUDygCaVV41JhREN2QDxh9RCkTNu5Ad3mg wqRfhiH8n3vWf6j1PShMo/L6RJQdJlcsXL/5w6ewXZRdRowBKhp8kNaUpGB8IQRAWYdy Vwc585Q5x+Xmxfm/ulKFAoNHmQ98ZPAYYra7dSMOf8Ekk4zKs3No8iT8zNK+a0mFjVXn AkWg== X-Gm-Message-State: APjAAAVIzvu+NUOjhcbQnaUXOsseXIX3MPeXDFsxeEFU1r88+J7CkVRN lQzf778Lo9N57Lb8rqZUxbju4Il4hWSGZt1e X-Google-Smtp-Source: APXvYqyQYFo/SVqLudHuBq0akKPCDJONWrXAYKTaEfxtfHzCYvYIvxkO/0zufmfXYgX8y9D4iHgx4ShS3grBopTf X-Received: by 2002:a05:6000:142:: with SMTP id r2mr20520344wrx.30.1572366756966; Tue, 29 Oct 2019 09:32:36 -0700 (PDT) Date: Tue, 29 Oct 2019 17:32:26 +0100 Message-Id: Mime-Version: 1.0 X-Mailer: git-send-email 2.24.0.rc0.303.g954a862665-goog Subject: [PATCH v3 0/3] kcov: collect coverage from usb and vhost From: Andrey Konovalov To: linux-usb@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Dmitry Vyukov , Greg Kroah-Hartman , Alan Stern , "Michael S . Tsirkin" , Jason Wang Cc: Andrew Morton , Arnd Bergmann , Steven Rostedt , David Windsor , Elena Reshetova , Anders Roxell , Alexander Potapenko , Marco Elver , Andrey Konovalov Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org This patchset extends kcov to allow collecting coverage from backgound kernel threads. This extension requires custom annotations for each of the places where coverage collection is desired. This patchset implements this for hub events in the USB subsystem and for vhost workers. See the first patch description for details about the kcov extension. The other two patches apply this kcov extension to USB and vhost. Examples of other subsystems that might potentially benefit from this when custom annotations are added (the list is based on process_one_work() callers for bugs recently reported by syzbot): 1. fs: writeback wb_workfn() worker, 2. net: addrconf_dad_work()/addrconf_verify_work() workers, 3. net: neigh_periodic_work() worker, 4. net/p9: p9_write_work()/p9_read_work() workers, 5. block: blk_mq_run_work_fn() worker. These patches have been used to enable coverage-guided USB fuzzing with syzkaller for the last few years, see the details here: https://github.com/google/syzkaller/blob/master/docs/linux/external_fuzzing_usb.md This patchset has been pushed to the public Linux kernel Gerrit instance: https://linux-review.googlesource.com/c/linux/kernel/git/torvalds/linux/+/1524 Changes v2 -> v3: - Removed using u64 division as arm can't do that. - Added EXPORT_SYMBOL() for kcov_common_handle(), kcov_remote_start() and kcov_remote_stop(). - Added usage comments for kcov_remote_start(), kcov_remote_stop() and kcov_common_handle(). - Expanded a comment in kcov_task_exit() to better explain WARN_ON() condition. - Reduced KCOV_REMOTE_MAX_HANDLES to 0x100 to avoid allowing too many GFP_ATOMIC allocations. Changes v1 -> v2: - Changed common_handle type back to u64 (to allow extending it in the future). - Reworked kcov_remote_handle() helpers. - Fixed vhost annotations when CONFIG_KCOV is not enabled. - Use kcov_disable() instead of kcov_remote_reset() when KCOV_REMOTE_ENABLE fails. Changes RFC v1 -> v1: - Remove unnecessary #ifdef's from drivers/vhost/vhost.c. - Reset t->kcov when area allocation fails in kcov_remote_start(). - Use struct_size to calculate array size in kcov_ioctl(). - Add a limit on area_size in kcov_remote_arg. - Added kcov_disable() helper. - Changed encoding of kcov remote handle ids, see the documentation. - Added a comment reference for kcov_sequence task_struct field. - Change common_handle type to u32. - Add checks for handle validity into kcov_ioctl_locked() and kcov_remote_start(). - Updated documentation to reflect the changes. Reviewed-by: Dmitry Vyukov Signed-off-by: Andrey Konovalov Andrey Konovalov (3): kcov: remote coverage support usb, kcov: collect coverage from hub_event vhost, kcov: collect coverage from vhost_worker Documentation/dev-tools/kcov.rst | 129 ++++++++ drivers/usb/core/hub.c | 5 + drivers/vhost/vhost.c | 6 + drivers/vhost/vhost.h | 1 + include/linux/kcov.h | 23 ++ include/linux/sched.h | 8 + include/uapi/linux/kcov.h | 28 ++ kernel/kcov.c | 547 +++++++++++++++++++++++++++++-- 8 files changed, 712 insertions(+), 35 deletions(-)