From: Miaohe Lin <linmiaohe@huawei.com>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: <akpm@linux-foundation.org>, <hannes@cmpxchg.org>,
<mhocko@suse.com>, <iamjoonsoo.kim@lge.com>, <vbabka@suse.cz>,
<alex.shi@linux.alibaba.com>, <willy@infradead.org>,
<minchan@kernel.org>, <richard.weiyang@gmail.com>,
<hughd@google.com>, <tim.c.chen@linux.intel.com>,
<linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>
Subject: Re: [PATCH 5/5] mm/swap_state: fix swap_cluster_readahead() race with swapoff
Date: Wed, 14 Apr 2021 10:43:10 +0800 [thread overview]
Message-ID: <444ce6f6-9ba7-6161-6429-85b01561ad5e@huawei.com> (raw)
In-Reply-To: <87eeffufst.fsf@yhuang6-desk1.ccr.corp.intel.com>
On 2021/4/13 9:36, Huang, Ying wrote:
> Miaohe Lin <linmiaohe@huawei.com> writes:
>
>> swap_cluster_readahead() could race with swapoff and might dereference
>> si->swap_file after it's released by swapoff. Close this race window by
>> using get/put_swap_device() pair.
>
> I think we should fix the callers instead to reduce the overhead. Now,
> do_swap_page() has been fixed. We need to fix shmem_swapin().
>
Will do. Many thanks.
> Best Regards,
> Huang, Ying
>
>> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
>> ---
>> mm/swap_state.c | 11 +++++++++--
>> 1 file changed, 9 insertions(+), 2 deletions(-)
>>
>> diff --git a/mm/swap_state.c b/mm/swap_state.c
>> index 3bf0d0c297bc..eba6b0cf6cf9 100644
>> --- a/mm/swap_state.c
>> +++ b/mm/swap_state.c
>> @@ -626,12 +626,17 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask,
>> unsigned long offset = entry_offset;
>> unsigned long start_offset, end_offset;
>> unsigned long mask;
>> - struct swap_info_struct *si = swp_swap_info(entry);
>> + struct swap_info_struct *si;
>> struct blk_plug plug;
>> bool do_poll = true, page_allocated;
>> struct vm_area_struct *vma = vmf->vma;
>> unsigned long addr = vmf->address;
>>
>> + si = get_swap_device(entry);
>> + /* In case we raced with swapoff. */
>> + if (!si)
>> + return NULL;
>> +
>> mask = swapin_nr_pages(offset) - 1;
>> if (!mask)
>> goto skip;
>> @@ -673,7 +678,9 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask,
>>
>> lru_add_drain(); /* Push any new pages onto the LRU now */
>> skip:
>> - return read_swap_cache_async(entry, gfp_mask, vma, addr, do_poll);
>> + page = read_swap_cache_async(entry, gfp_mask, vma, addr, do_poll);
>> + put_swap_device(si);
>> + return page;
>> }
>>
>> int init_swap_address_space(unsigned int type, unsigned long nr_pages)
> .
>
next prev parent reply other threads:[~2021-04-14 2:43 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-08 13:08 [PATCH 0/5] close various race windows for swap Miaohe Lin
2021-04-08 13:08 ` [PATCH 1/5] mm/swapfile: add percpu_ref support " Miaohe Lin
2021-04-12 3:30 ` Huang, Ying
2021-04-12 6:59 ` Miaohe Lin
2021-04-12 7:24 ` Huang, Ying
2021-04-13 12:39 ` Miaohe Lin
2021-04-14 1:17 ` Huang, Ying
2021-04-14 1:58 ` Miaohe Lin
2021-04-14 2:06 ` Huang, Ying
2021-04-14 3:44 ` Dennis Zhou
2021-04-14 3:59 ` Huang, Ying
2021-04-14 4:05 ` Dennis Zhou
2021-04-14 5:44 ` Huang, Ying
2021-04-14 14:53 ` Dennis Zhou
2021-04-15 3:16 ` Miaohe Lin
2021-04-15 4:20 ` Dennis Zhou
2021-04-15 9:17 ` Miaohe Lin
2021-04-15 5:24 ` Huang, Ying
2021-04-15 14:31 ` Dennis Zhou
2021-04-16 0:54 ` Huang, Ying
2021-04-16 2:27 ` Miaohe Lin
2021-04-16 6:25 ` Huang, Ying
2021-04-16 8:30 ` Miaohe Lin
2021-04-08 13:08 ` [PATCH 2/5] swap: fix do_swap_page() race with swapoff Miaohe Lin
2021-04-08 21:34 ` Tim Chen
2021-04-09 8:42 ` Miaohe Lin
2021-04-09 17:17 ` Tim Chen
2021-04-10 3:17 ` Miaohe Lin
2021-04-12 1:44 ` Huang, Ying
2021-04-12 3:24 ` Miaohe Lin
2021-04-13 1:27 ` Huang, Ying
2021-04-13 19:24 ` Tim Chen
2021-04-14 1:04 ` Huang, Ying
2021-04-14 2:20 ` Miaohe Lin
2021-04-14 16:13 ` Tim Chen
2021-04-15 3:19 ` Miaohe Lin
2021-04-14 2:55 ` Miaohe Lin
2021-04-14 3:07 ` Huang, Ying
2021-04-14 3:27 ` Miaohe Lin
2021-04-08 13:08 ` [PATCH 3/5] mm/swap_state: fix get_shadow_from_swap_cache() " Miaohe Lin
2021-04-13 1:33 ` Huang, Ying
2021-04-14 2:42 ` Miaohe Lin
2021-04-08 13:08 ` [PATCH 4/5] mm/swap_state: fix potential faulted in race in swap_ra_info() Miaohe Lin
2021-04-09 8:50 ` Huang, Ying
2021-04-09 9:00 ` Miaohe Lin
2021-04-12 0:55 ` Huang, Ying
2021-04-12 3:17 ` Miaohe Lin
2021-04-08 13:08 ` [PATCH 5/5] mm/swap_state: fix swap_cluster_readahead() race with swapoff Miaohe Lin
2021-04-13 1:36 ` Huang, Ying
2021-04-14 2:43 ` Miaohe Lin [this message]
2021-04-08 14:55 ` [PATCH 0/5] close various race windows for swap riteshh
2021-04-09 8:01 ` Miaohe Lin
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