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=-8.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_MUTT autolearn=unavailable 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 19288C10F06 for ; Mon, 11 Mar 2019 12:55:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D71C42075C for ; Mon, 11 Mar 2019 12:55:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Gx0tOjH7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727291AbfCKMzD (ORCPT ); Mon, 11 Mar 2019 08:55:03 -0400 Received: from mail-ot1-f66.google.com ([209.85.210.66]:44406 "EHLO mail-ot1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726605AbfCKMzD (ORCPT ); Mon, 11 Mar 2019 08:55:03 -0400 Received: by mail-ot1-f66.google.com with SMTP id g1so3783524otj.11; Mon, 11 Mar 2019 05:55:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:reply-to:references :mime-version:content-disposition:in-reply-to:user-agent; bh=XjRDh4ky7Pn/jY4wlA16VBNGdh5xpSfShrnXXpefjYA=; b=Gx0tOjH7fUxrWVo0gvNz2AU7P+fq0VN0weB8+iR5VUg1AmXv37+dIgAJ4/HIJaWIG1 OKb8vTbgCdZvMC2Vb+vxfXnGbJMGXGGelQnJz2VG7DHmT2her5P2C/ORzTQgEaki+F/B it3qDyyYyoJ1eDqaxbCfDCrST0xlTkXX/T2emN+C48NYCRImoklGmROAoeK66gptSAI0 NezvuqvWzCORVhydHKmNCljTu0kAQM0RWmr76hfiFlX60fGYs21cvj3c3IjMffcm7qLi ZWOdsXT0Sqit5Z+kxgFrpUdRZPHRwIe1o7sIEw8u6WOpEmiQ+DF/kfDsJ3VjkYpeNnBa wNyw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :reply-to:references:mime-version:content-disposition:in-reply-to :user-agent; bh=XjRDh4ky7Pn/jY4wlA16VBNGdh5xpSfShrnXXpefjYA=; b=d3XdimZJ4PjfiF8y3GMLjOQJR2B+bZogYj4CUHuJFuR0Xu3w5OtxZ1OPURZkx4XJya Ok4G/f70H5RKhalGhX8xb58NNHOukh59e8PGg4prRclkA1kRsdG4TfQMQ6pDIHjID64x Nh4bw4Z+/72MFzOej0PqWXEw+0ldbEYbdPvPSA/RLCGOK6rrkFdQeKPqTuzYRnkdnq4E +RovtYNBDLSX/eavVVoktXX1og8C8Ggwusq1iS472lp0mYemm6S9hCAqXpKFUt19XImT STGE6xopHLs8G4uZLLsDYfSAVDKy13yyFQAiRGMjEUKOTjg0usoEfT6XzOxQUBAIapTV FfMA== X-Gm-Message-State: APjAAAUIOSmzRxBAUH1IcmGyAw8bKSOGE87DtzW29fyt8SEVdORdGFl7 bhvMD+ZdhCfdZ8+2wIiqmv6OE3A= X-Google-Smtp-Source: APXvYqxpsAhaOOFG2v8heO45MrcYkrZma9uQeKG5NjozkFf3rN6IQj7FcjP9Y4jvb+a6fQM02S7PpQ== X-Received: by 2002:a9d:66f:: with SMTP id 102mr20644425otn.340.1552308902394; Mon, 11 Mar 2019 05:55:02 -0700 (PDT) Received: from serve.minyard.net ([47.184.128.64]) by smtp.gmail.com with ESMTPSA id l63sm2277352oia.47.2019.03.11.05.55.01 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 11 Mar 2019 05:55:01 -0700 (PDT) Received: from minyard.net (unknown [IPv6:2001:470:b8f6:1b:dd3c:1d89:d3d4:f9e3]) by serve.minyard.net (Postfix) with ESMTPSA id 45FC7180001; Mon, 11 Mar 2019 12:55:01 +0000 (UTC) Date: Mon, 11 Mar 2019 07:54:59 -0500 From: Corey Minyard To: Konstantin Khlebnikov Cc: openipmi-developer@lists.sourceforge.net, linux-kernel@vger.kernel.org, Yang Yingliang , stable@vger.kernel.org Subject: Re: [PATCH] ipmi: fix sleep-in-atomic in free_user at cleanup SRCU user->release_barrier Message-ID: <20190311125459.GA3498@minyard.net> Reply-To: minyard@acm.org References: <155229854905.2133.15708039732382992559.stgit@buzz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <155229854905.2133.15708039732382992559.stgit@buzz> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 11, 2019 at 01:02:29PM +0300, Konstantin Khlebnikov wrote: > free_user() could be called in atomic context. > > This patch uses non-sleeping cleanup_srcu_struct_quiesced(). At this stage > atomic refcount is zero, thus all read-sections should have been ended. Thanks, I have this in my tree. -corey > > Example: > > BUG: sleeping function called from invalid context at kernel/workqueue.c:2856 > in_atomic(): 1, irqs_disabled(): 0, pid: 177, name: ksoftirqd/27 > CPU: 27 PID: 177 Comm: ksoftirqd/27 Not tainted 4.19.25-3 #1 > Hardware name: AIC 1S-HV26-08/MB-DPSB04-06, BIOS IVYBV060 10/21/2015 > Call Trace: > dump_stack+0x5c/0x7b > ___might_sleep+0xec/0x110 > __flush_work+0x48/0x1f0 > ? try_to_del_timer_sync+0x4d/0x80 > _cleanup_srcu_struct+0x104/0x140 > free_user+0x18/0x30 [ipmi_msghandler] > ipmi_free_recv_msg+0x3a/0x50 [ipmi_msghandler] > deliver_response+0xbd/0xd0 [ipmi_msghandler] > deliver_local_response+0xe/0x30 [ipmi_msghandler] > handle_one_recv_msg+0x163/0xc80 [ipmi_msghandler] > ? dequeue_entity+0xa0/0x960 > handle_new_recv_msgs+0x15c/0x1f0 [ipmi_msghandler] > tasklet_action_common.isra.22+0x103/0x120 > __do_softirq+0xf8/0x2d7 > run_ksoftirqd+0x26/0x50 > smpboot_thread_fn+0x11d/0x1e0 > kthread+0x103/0x140 > ? sort_range+0x20/0x20 > ? kthread_destroy_worker+0x40/0x40 > ret_from_fork+0x1f/0x40 > > Fixes: 77f8269606bf ("ipmi: fix use-after-free of user->release_barrier.rda") > Signed-off-by: Konstantin Khlebnikov > Cc: stable@vger.kernel.org # 4.18 > Cc: Yang Yingliang > Cc: Corey Minyard > --- > drivers/char/ipmi/ipmi_msghandler.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c > index e8ba67834746..c35f2bcbaa23 100644 > --- a/drivers/char/ipmi/ipmi_msghandler.c > +++ b/drivers/char/ipmi/ipmi_msghandler.c > @@ -1260,7 +1260,12 @@ EXPORT_SYMBOL(ipmi_get_smi_info); > static void free_user(struct kref *ref) > { > struct ipmi_user *user = container_of(ref, struct ipmi_user, refcount); > - cleanup_srcu_struct(&user->release_barrier); > + > + /* > + * Cleanup without waiting. This could be called in atomic context. > + * Refcount is zero: all read-sections should have been ended. > + */ > + cleanup_srcu_struct_quiesced(&user->release_barrier); > kfree(user); > } > >