From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AB8JxZrTwOdSNThJlVCGXTYaa/r/1hin1L5BGuEMzJ1BFmc9Om8clTc5lK9Q58naB6VEG+JE86F0 ARC-Seal: i=1; a=rsa-sha256; t=1524840987; cv=none; d=google.com; s=arc-20160816; b=Mkn6g7dMeV1KE2GNVNscHo2VFXC9buRxHcDTJAnMGMw2BaBfFbuVgF0qVFJFxI/vBg IDCJ3TJnSdX4g1cWuzGbWge+aACdHTtRONayftzw/rGKZpnkhRrsE8oqZS5xZhNHO2To by8QtoRyDnvW8jbAJgeIp5WAbyA9fjO7YteDC9qNRzlcPJjnzp53c308IcOkYrMfKPAE KDNHyFSYn5aJMiTGsQahbT/F9HhnIqztWGPVaHpU8OjKnF9JYRjUrQnHWN5N3igW2lNo ZKKUscG3OQ2I0achBEndh37862dWfiA1FN1SXNtvk2tfAJLWcZrajfOcOkpwa2B3cKmg YABQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:arc-authentication-results; bh=e8uRL9cRG1PeG5NsOUd+MKj9MqdCqMoQkoD2JWZ+Cao=; b=NJYSgVsuP7ZLhYyXbSzwXJjO2p2iqjAq5zWQN8cKB8txxD2iBpf3ge8ejq6Cag2k/Y WEzm1swycR4ZZ6iqJwCMLzgymLnTMneMkV3g+IW60/mrmHcMF2vik2MakkJlsTludmgm SoVGJZt6BpnAvYLkT508DZdEuUCaKqhgn14o1xtPkdKU71Sn/+zSTkUE2GUwDuUrlAIf RDDkHulIpje40IV04hEAOn72WD7jkzvCW0+IStivYJCC2KYEm1x5NonurmYO2GOWRdNO V7dU4943cq/kFuUbKvRcwVDt2z6Ppaeo32NqwBu7kwll83IMeefDW4PHam86IvC8ARGn 3Uhw== ARC-Authentication-Results: i=1; mx.google.com; spf=neutral (google.com: 195.135.220.15 is neither permitted nor denied by best guess record for domain of mhocko@kernel.org) smtp.mailfrom=mhocko@kernel.org Authentication-Results: mx.google.com; spf=neutral (google.com: 195.135.220.15 is neither permitted nor denied by best guess record for domain of mhocko@kernel.org) smtp.mailfrom=mhocko@kernel.org Date: Fri, 27 Apr 2018 16:56:23 +0200 From: Michal Hocko To: Arvind Yadav Cc: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: memory_hotplug: use put_device() if device_register fail Message-ID: <20180427145623.GC5404@dhcp22.suse.cz> References: <2987b5bdb31e7c18cd837da0f1e32a98fecd3278.1524757165.git.arvind.yadav.cs@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2987b5bdb31e7c18cd837da0f1e32a98fecd3278.1524757165.git.arvind.yadav.cs@gmail.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1598823954747248901?= X-GMAIL-MSGID: =?utf-8?q?1598911663397378638?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Thu 26-04-18 21:12:09, Arvind Yadav wrote: > if device_register() returned an error. Always use put_device() > to give up the initialized reference and release allocated memory. Is this patch correct? The docummentation says * NOTE: _Never_ directly free @dev after calling this function, even * if it returned an error! Always use put_device() to give up your * reference instead. but we do not have _our_ reference in this path AFAICS. Maybe this is just a documentation issue? How have you tested this change btw.? > Signed-off-by: Arvind Yadav > --- > drivers/base/memory.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/base/memory.c b/drivers/base/memory.c > index bffe861..f5e5601 100644 > --- a/drivers/base/memory.c > +++ b/drivers/base/memory.c > @@ -649,13 +649,19 @@ static const struct attribute_group *memory_memblk_attr_groups[] = { > static > int register_memory(struct memory_block *memory) > { > + int ret; > + > memory->dev.bus = &memory_subsys; > memory->dev.id = memory->start_section_nr / sections_per_block; > memory->dev.release = memory_block_release; > memory->dev.groups = memory_memblk_attr_groups; > memory->dev.offline = memory->state == MEM_OFFLINE; > > - return device_register(&memory->dev); > + ret = device_register(&memory->dev); > + if (ret) > + put_device(&memory->dev); > + > + return ret; > } > > static int init_memory_block(struct memory_block **memory, > -- > 2.7.4 -- Michal Hocko SUSE Labs