From: Dave Hansen <dave.hansen@intel.com>
To: Jarkko Sakkinen <jarkko@kernel.org>, linux-sgx@vger.kernel.org
Cc: stable@vger.kernel.org, Dave Hansen <dave.hansen@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Jethro Beekman <jethro@fortanix.com>,
Sean Christopherson <seanjc@google.com>,
Serge Ayoun <serge.ayoun@intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 1/5] x86/sgx: Fix a resource leak in sgx_init()
Date: Wed, 3 Mar 2021 08:56:52 -0800 [thread overview]
Message-ID: <57b33fb5-f961-5c81-72f1-ebf5e6af671c@intel.com> (raw)
In-Reply-To: <20210303150323.433207-2-jarkko@kernel.org>
On 3/3/21 7:03 AM, Jarkko Sakkinen wrote:
> If sgx_page_cache_init() fails in the middle, a trivial return
> statement causes unused memory and virtual address space reserved for
> the EPC section, not freed. Fix this by using the same rollback, as
> when sgx_page_reclaimer_init() fails.
...
> @@ -708,8 +708,10 @@ static int __init sgx_init(void)
> if (!cpu_feature_enabled(X86_FEATURE_SGX))
> return -ENODEV;
>
> - if (!sgx_page_cache_init())
> - return -ENOMEM;
> + if (!sgx_page_cache_init()) {
> + ret = -ENOMEM;
> + goto err_page_cache;
> + }
Currently, the only way sgx_page_cache_init() can fail is in the case
that there are no sections:
if (!sgx_nr_epc_sections) {
pr_err("There are zero EPC sections.\n");
return false;
}
That only happened if all sgx_setup_epc_section() calls failed.
sgx_setup_epc_section() never both allocates memory with vmalloc for
section->pages *and* fails. If sgx_setup_epc_section() has a successful
memremap() but a failed vmalloc(), it cleans up with memunmap().
In other words, I see how this _looks_ like a memory leak from
sgx_init(), but I don't see an actual leak in practice.
Am I missing something?
next prev parent reply other threads:[~2021-03-05 17:39 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210303150323.433207-1-jarkko@kernel.org>
2021-03-03 15:03 ` [PATCH v3 1/5] x86/sgx: Fix a resource leak in sgx_init() Jarkko Sakkinen
2021-03-03 16:56 ` Dave Hansen [this message]
2021-03-10 15:00 ` Jarkko Sakkinen
2021-03-10 15:49 ` Sean Christopherson
2021-03-10 21:52 ` Jarkko Sakkinen
2021-03-03 15:03 ` [PATCH v3 2/5] x86/sgx: Use sgx_free_epc_page() in sgx_reclaim_pages() Jarkko Sakkinen
2021-03-03 16:59 ` Dave Hansen
2021-03-10 15:11 ` Jarkko Sakkinen
2021-03-10 15:55 ` Dave Hansen
2021-03-10 21:56 ` Jarkko Sakkinen
2021-03-10 20:36 ` Kai Huang
2021-03-10 22:10 ` Jarkko Sakkinen
2021-03-10 22:12 ` Jarkko Sakkinen
2021-03-10 22:35 ` Jarkko Sakkinen
2021-03-10 22:43 ` Kai Huang
2021-03-10 22:52 ` Kai Huang
2021-03-03 15:03 ` [PATCH v3 3/5] x86/sgx: Replace section->init_laundry_list with a temp list Jarkko Sakkinen
2021-03-03 18:02 ` Dave Hansen
2021-03-10 14:50 ` Jarkko Sakkinen
2021-03-03 15:03 ` [PATCH v3 4/5] x86/sgx: Replace section->page_list with a global free page list Jarkko Sakkinen
2021-03-03 23:48 ` Dave Hansen
2021-03-10 10:54 ` Jarkko Sakkinen
2021-03-03 15:03 ` [PATCH v3 5/5] x86/sgx: Add a basic NUMA allocation scheme to sgx_alloc_epc_page() Jarkko Sakkinen
2021-03-04 0:20 ` Dave Hansen
2021-03-10 11:30 ` Jarkko Sakkinen
2021-03-10 15:44 ` Dave Hansen
2021-03-10 21:48 ` Jarkko Sakkinen
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