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b=JKCK0sjq6RbbyX/DE11Li7nGowizchrK69kf42YjqhNx4iV5qc3Xhp1Y/7nUUQEWiDVYD/O2NJcNI0opuFTR77JmdN49elkGcaJKoiOYe4hAMC8okO7+E6DkYYW5iEOesa9MX3RDKqYjicsBx1o3DiDLHoy+/UaJaNBqoV2WM8g= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R141e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam033045098064;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=15;SR=0;TI=SMTPD_---0X6tcPXS_1783915201; Received: from 30.74.144.131(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0X6tcPXS_1783915201 cluster:ay36) by smtp.aliyun-inc.com; Mon, 13 Jul 2026 12:00:01 +0800 Message-ID: <368ddc3f-1206-4e2b-a45b-c67b0f54c58b@linux.alibaba.com> Date: Mon, 13 Jul 2026 12:00:00 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm: huge_memory: Fix kobject cleanup in thpsize_create error To: Hongling Zeng , akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, ziy@nvidia.com, liam@infradead.org, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, zhongling0719@126.com, stable@vger.kernel.org References: <20260711084624.207777-1-zenghongling@kylinos.cn> From: Baolin Wang In-Reply-To: <20260711084624.207777-1-zenghongling@kylinos.cn> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 50985C0002 X-Rspam-User: X-Stat-Signature: x1imw18bguqp4e95w9kfa4zy59i4u4t8 X-Rspamd-Server: rspam03 X-HE-Tag: 1783915206-796318 X-HE-Meta: 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 08Nqhbc5 zDD1GZAT4bxzQTVjTAcZbDSp9QkzWgN5IJFIHRxU3Z7R0vk0veEEY9qw5dIkfxxu+KUYvCbHiMei8aDK3xW0k3U7t2xakw/97DnpFnoIEX9JOIXW9c9lDoytOjDXcMoJW+b99VZsE5OyhtnSJWqkNHEJl5UDVap6DnOL4AY6wr6vRxcdfkG3Bc5a/WCICfobOJ4UeLl8U5xpaKUzGeF40Gsnbe3LccNJOm4G3exPuReGfMkpDiu8b75e7MTIeeRvzRoP08axKh5A1xBDByvz5ax0GikstwbmWN5fRq6GR5T6Ql1ByfeEMLCM4tRqg64QkaFNK5fbLmjICVRFXO2/K/e3AkSTGk+UVMbONGAcJA/RqM5BtA4onnX579fnmNfaMkZb/m53ombNh/YvTXw+oBsLsGQw7hZd1NZFTR9uFgaATqzMCObWBpSzf5h7oMy93bxerJGygCUGGwSdHedoFGcoSrg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 7/11/26 4:46 PM, Hongling Zeng wrote: > When kobject_init_and_add() fails, the kobject API requires calling > kobject_put() to properly clean up the memory, not direct kfree(). > > According to the kobject API documentation, kobject_init_and_add() > calls kobject_init() internally. If the subsequent kobject_add() > fails, the kobject has still been initialized and must be cleaned up > via the reference count mechanism (kobject_put), not direct kfree(). > > Direct kfree() leaves the kobject's internal state (including the > reference count and kset membership) uncleaned, which can cause: > - Memory leaks of kobject internal structures > - Potential use-after-free if there are pending references > - Inconsistent state with the rest of the error handling code > > This fix matches the pattern used elsewhere in the kernel and in the > same function (err_put label) which correctly uses kobject_put(). > > Fixes: 3485b88390b0 ("mm: thp: introduce multi-size THP sysfs interface") > Cc: stable@vger.kernel.org I don't think this need to CC stable. > Signed-off-by: Hongling Zeng > --- A related fix was already sent before[1]. As noted in the previous comments, just change it to 'goto err_put'. [1] https://lore.kernel.org/all/20260412175428.2613383-1-lgs201920130244@gmail.com/ > mm/huge_memory.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 2bccb0a53a0a..7aeb17d60ac7 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -819,7 +819,7 @@ static struct thpsize *thpsize_create(int order, struct kobject *parent) > ret = kobject_init_and_add(&thpsize->kobj, &thpsize_ktype, parent, > "hugepages-%lukB", size); > if (ret) { > - kfree(thpsize); > + kobject_put(&thpsize->kobj); > goto err; > } >