On Mon, 2013-04-15 at 14:48 +0900, 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@xxxxxxxxxxxxxx>
Acked-by: Toshi Kani <toshi.kani@xxxxxx>
Thanks,
-Toshi
> ---
> 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;
> }
>
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