linux-kernel - Re: [PATCH] firmware, memmap: fix firmware_map

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <516C8F23.7050209@jp.fujitsu.com>
Date:	Tue, 16 Apr 2013 08:37:07 +0900
From:	Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
To:	Tang Chen <tangchen@...fujitsu.com>
CC:	<akpm@...ux-foundation.org>, <linux-kernel@...r.kernel.org>,
	<linux-mm@...ck.org>, <wency@...fujitsu.com>, <toshi.kani@...com>
Subject: Re: [PATCH] firmware, memmap: fix firmware_map_entry leak

2013/04/15 18:03, Tang Chen wrote:
> 
> Reviewed-by: Tang Chen <tangchen@...fujitsu.com>

Thank you for your review.

Thanks,
Yasuaki Ishimatsu

> 
> Thanks. :)
> 
> On 04/15/2013 01:48 PM, Yasuaki Ishimatsu wrote:
>> When hot removing a memory, a firmware_map_entry which has memory range
>> of the memory is released by release_firmware_map_entry(). If the entry
>> is allocated by bootmem, release_firmware_map_entry() adds the entry to
>> map_entires_bootmem list when firmware_map_find_entry() finds the entry
>> from map_entries list. But firmware_map_find_entry never find the entry
>> sicne map_entires list does not have the entry. So the entry just leaks.
>>
>> Here are steps of leaking firmware_map_entry:
>> firmware_map_remove()
>> ->  firmware_map_find_entry()
>>      Find released entry from map_entries list
>> ->  firmware_map_remove_entry()
>>      Delete the entry from map_entries list
>> ->  remove_sysfs_fw_map_entry()
>>      ...
>>      ->  release_firmware_map_entry()
>>         ->  firmware_map_find_entry()
>>            Find the entry from map_entries list but the entry has been
>>            deleted from map_entries list. So the entry is not added
>>            to map_entries_bootmem. Thus the entry leaks
>>
>> release_firmware_map_entry() should not call firmware_map_find_entry()
>> since releaed entry has been deleted from map_entries list.
>> So the patch delete firmware_map_find_entry() from releae_firmware_map_entry()
>>
>> Signed-off-by: Yasuaki Ishimatsu<isimatu.yasuaki@...fujitsu.com>
>> ---
>>    drivers/firmware/memmap.c |    9 +++------
>>    1 files changed, 3 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/firmware/memmap.c b/drivers/firmware/memmap.c
>> index 0b5b5f6..e2e04b0 100644
>> --- a/drivers/firmware/memmap.c
>> +++ b/drivers/firmware/memmap.c
>> @@ -114,12 +114,9 @@ static void __meminit release_firmware_map_entry(struct kobject *kobj)
>>    		 * map_entries_bootmem here, and deleted from&map_entries in
>>    		 * firmware_map_remove_entry().
>>    		 */
>> -		if (firmware_map_find_entry(entry->start, entry->end,
>> -		    entry->type)) {
>> -			spin_lock(&map_entries_bootmem_lock);
>> -			list_add(&entry->list,&map_entries_bootmem);
>> -			spin_unlock(&map_entries_bootmem_lock);
>> -		}
>> +		spin_lock(&map_entries_bootmem_lock);
>> +		list_add(&entry->list,&map_entries_bootmem);
>> +		spin_unlock(&map_entries_bootmem_lock);
>>
>>    		return;
>>    	}
>>
>>


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/