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 <[email protected]>
Reviewed-by: Wanpeng Li <[email protected]>
Reviewed-by: Tang Chen <[email protected]>
Acked-by: Toshi Kani <[email protected]>
Cc: Wen Congyang <[email protected]>
Cc: Greg KH <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/drivers/firmware/memmap.c b/drivers/firmware/memmap.c
index 0b5b5f619c7559d2b68284fdba6cf1a8e5c94dd7..e2e04b007e155954a405a53f7117000d03ccfc1e 100644 (file)
--- 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;
        }