Re: [PATCH] firmware, memmap: fix firmware_map_entry leak

From: Yasuaki Ishimatsu
Date: Mon Apr 15 2013 - 19:38:39 EST

2013/04/16 6:00, Toshi Kani wrote:
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_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>

Thank you for your review.

Yasuaki Ishimatsu


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);


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at