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=-23.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL 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 AECD9C4320A for ; Thu, 2 Sep 2021 15:35:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 928E361074 for ; Thu, 2 Sep 2021 15:35:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345872AbhIBPgv (ORCPT ); Thu, 2 Sep 2021 11:36:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345822AbhIBPgr (ORCPT ); Thu, 2 Sep 2021 11:36:47 -0400 Received: from mail-lj1-x236.google.com (mail-lj1-x236.google.com [IPv6:2a00:1450:4864:20::236]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4C21AC061757 for ; Thu, 2 Sep 2021 08:35:49 -0700 (PDT) Received: by mail-lj1-x236.google.com with SMTP id m4so4327726ljq.8 for ; Thu, 02 Sep 2021 08:35:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=gqsE0hcACBYtzOEUSRWmq502BlYXjpyMpHHF4zb++1Y=; b=YvMoLhTqope6Anvbg2E/49DdR0bfBTbd3WBFEpizcH0H43hqwki7cGgzsjtRtm+AoT 38FGEfBZmCZH/fn2WSrE++8YwficAwTcjLRvKO3D6bSuwFqVx5xBEgPxK9YLo7hVU5rj dPqO+SLEHJoOqbsTFmWAXZ9/nLfrf980M/fNjCa6aDWHW3jRJis7MGBQyl0ZmGZ4Gnpg 8LO/NCLH8ziH2DY+BmiRAIvw9INsp90XK5BE73m7OhmMpz2/99leispqO6agIGSvQtXh 1qQ6+kgAfUZY0Do2zuglHu0P6NbjVln1NC3EVkF46q0Ufila1YAXVB5lZAvfabZFqDG5 YACg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=gqsE0hcACBYtzOEUSRWmq502BlYXjpyMpHHF4zb++1Y=; b=WnT+J5HxiPaIapYLDP4p9j7pCs2PzBOtbQh5NLGGZbgisaEOeLWfc6BGJ7IznWCkdQ tNdnhso2Bslznn2jdiqXoL92Hbw7lIp9Y4ryEOD2JIZUf/MJP2lS8c0KY+Y5zh0OfIAI z0xDoZAJ+8C1Jszc3AB/XrkiJnMl+RKpDSR+YPXAe1dJpQ5M1msOsRFBM9tp12GR7fwX wbOghKKn4KlIEPbyUTzE3h4VofAanim86yX43AgMx2kEBWZNQ6YoNYLYuVuhRPwHxJEN gOfDvKAulNyy47bwitCtz2AfxdzsVmOrcXiHRkz55nApn5dOLBFhBLLHix9u5Uja3aI8 PNrg== X-Gm-Message-State: AOAM533EAXavDJ/0mALOs2L+MDm5eG7NhJtlfwqWZflT4EmzaQvf1mtT c1Nm9+dSoG2j5Hxv1XvRPDClB3KzeJM40aCLWrK7XQ== X-Google-Smtp-Source: ABdhPJzJ2ZXLD2ye7fiTVTjas7hr69B87RP5P3F3ORamACWW63F58/LqhV8yp2vp3VXog/b65mHOHs0VwizfSYBzHlQ= X-Received: by 2002:a05:651c:118f:: with SMTP id w15mr3130589ljo.47.1630596947384; Thu, 02 Sep 2021 08:35:47 -0700 (PDT) MIME-Version: 1.0 References: <20210830195146.587206-1-tkjos@google.com> In-Reply-To: From: Todd Kjos Date: Thu, 2 Sep 2021 08:35:35 -0700 Message-ID: Subject: Re: [PATCH] binder: make sure fd closes complete To: Martijn Coenen Cc: Greg KH , Christian Brauner , =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= , "open list:ANDROID DRIVERS" , LKML , Martijn Coenen , Joel Fernandes , kernel-team@android.com, stable Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 31, 2021 at 12:24 AM Martijn Coenen wrote: > > On Mon, Aug 30, 2021 at 9:51 PM 'Todd Kjos' via kernel-team > wrote: > > > > During BC_FREE_BUFFER processing, the BINDER_TYPE_FDA object > > cleanup may close 1 or more fds. The close operations are > > completed using the task work mechanism -- which means the thread > > needs to return to userspace or the file object may never be > > dereferenced -- which can lead to hung processes. > > > > Force the binder thread back to userspace if an fd is closed during > > BC_FREE_BUFFER handling. > > > > Signed-off-by: Todd Kjos > Reviewed-by: Martijn Coenen Please also add to stable releases 5.4 and later. > > > --- > > drivers/android/binder.c | 23 +++++++++++++++++------ > > 1 file changed, 17 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/android/binder.c b/drivers/android/binder.c > > index bcec598b89f2..c2823f0d588f 100644 > > --- a/drivers/android/binder.c > > +++ b/drivers/android/binder.c > > @@ -1852,6 +1852,7 @@ static void binder_deferred_fd_close(int fd) > > } > > > > static void binder_transaction_buffer_release(struct binder_proc *proc, > > + struct binder_thread *thread, > > struct binder_buffer *buffer, > > binder_size_t failed_at, > > bool is_failure) > > @@ -2011,8 +2012,16 @@ static void binder_transaction_buffer_release(struct binder_proc *proc, > > &proc->alloc, &fd, buffer, > > offset, sizeof(fd)); > > WARN_ON(err); > > - if (!err) > > + if (!err) { > > binder_deferred_fd_close(fd); > > + /* > > + * Need to make sure the thread goes > > + * back to userspace to complete the > > + * deferred close > > + */ > > + if (thread) > > + thread->looper_need_return = true; > > + } > > } > > } break; > > default: > > @@ -3105,7 +3114,7 @@ static void binder_transaction(struct binder_proc *proc, > > err_copy_data_failed: > > binder_free_txn_fixups(t); > > trace_binder_transaction_failed_buffer_release(t->buffer); > > - binder_transaction_buffer_release(target_proc, t->buffer, > > + binder_transaction_buffer_release(target_proc, NULL, t->buffer, > > buffer_offset, true); > > if (target_node) > > binder_dec_node_tmpref(target_node); > > @@ -3184,7 +3193,9 @@ static void binder_transaction(struct binder_proc *proc, > > * Cleanup buffer and free it. > > */ > > static void > > -binder_free_buf(struct binder_proc *proc, struct binder_buffer *buffer) > > +binder_free_buf(struct binder_proc *proc, > > + struct binder_thread *thread, > > + struct binder_buffer *buffer) > > { > > binder_inner_proc_lock(proc); > > if (buffer->transaction) { > > @@ -3212,7 +3223,7 @@ binder_free_buf(struct binder_proc *proc, struct binder_buffer *buffer) > > binder_node_inner_unlock(buf_node); > > } > > trace_binder_transaction_buffer_release(buffer); > > - binder_transaction_buffer_release(proc, buffer, 0, false); > > + binder_transaction_buffer_release(proc, thread, buffer, 0, false); > > binder_alloc_free_buf(&proc->alloc, buffer); > > } > > > > @@ -3414,7 +3425,7 @@ static int binder_thread_write(struct binder_proc *proc, > > proc->pid, thread->pid, (u64)data_ptr, > > buffer->debug_id, > > buffer->transaction ? "active" : "finished"); > > - binder_free_buf(proc, buffer); > > + binder_free_buf(proc, thread, buffer); > > break; > > } > > > > @@ -4107,7 +4118,7 @@ static int binder_thread_read(struct binder_proc *proc, > > buffer->transaction = NULL; > > binder_cleanup_transaction(t, "fd fixups failed", > > BR_FAILED_REPLY); > > - binder_free_buf(proc, buffer); > > + binder_free_buf(proc, thread, buffer); > > binder_debug(BINDER_DEBUG_FAILED_TRANSACTION, > > "%d:%d %stransaction %d fd fixups failed %d/%d, line %d\n", > > proc->pid, thread->pid, > > -- > > 2.33.0.259.gc128427fd7-goog > > > >