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firmware, memmap: fix firmware_map_entry leak 

When hot removing 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@jp.fujitsu.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Tang Chen <tangchen@cn.fujitsu.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Yasuaki Ishimatsu 2013-04-29 15:08:39 -07:00 committed by Linus Torvalds
parent 40f4b1ead0
commit 7a6f93b0a8
1 changed files with 3 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
drivers/firmware/memmap.c
View File

@ -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;
}