This is a note to let you know that I've just added the patch titled
block: Fix possible memory leak for rq_wb on add_disk failure
to the 6.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
block-fix-possible-memory-leak-for-rq_wb-on-add_disk.patch
and it can be found in the queue-6.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 139b8b743770859b0194f8713151d5ce41939eae
Author: Chen Zhongjin <chenzhongjin@xxxxxxxxxx>
Date: Sat Oct 29 15:13:55 2022 +0800
block: Fix possible memory leak for rq_wb on add_disk failure
[ Upstream commit fa81cbafbf5764ad5053512152345fab37a1fe18 ]
kmemleak reported memory leaks in device_add_disk():
kmemleak: 3 new suspected memory leaks
unreferenced object 0xffff88800f420800 (size 512):
comm "modprobe", pid 4275, jiffies 4295639067 (age 223.512s)
hex dump (first 32 bytes):
04 00 00 00 08 00 00 00 01 00 00 00 00 00 00 00 ................
00 e1 f5 05 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<00000000d3662699>] kmalloc_trace+0x26/0x60
[<00000000edc7aadc>] wbt_init+0x50/0x6f0
[<0000000069601d16>] wbt_enable_default+0x157/0x1c0
[<0000000028fc393f>] blk_register_queue+0x2a4/0x420
[<000000007345a042>] device_add_disk+0x6fd/0xe40
[<0000000060e6aab0>] nbd_dev_add+0x828/0xbf0 [nbd]
...
It is because the memory allocated in wbt_enable_default() is not
released in device_add_disk() error path.
Normally, these memory are freed in:
del_gendisk()
rq_qos_exit()
rqos->ops->exit(rqos);
wbt_exit()
So rq_qos_exit() is called to free the rq_wb memory for wbt_init().
However in the error path of device_add_disk(), only
blk_unregister_queue() is called and make rq_wb memory leaked.
Add rq_qos_exit() to the error path to fix it.
Fixes: 83cbce957446 ("block: add error handling for device_add_disk / add_disk")
Signed-off-by: Chen Zhongjin <chenzhongjin@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Link: https://lore.kernel.org/r/20221029071355.35462-1-chenzhongjin@xxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/block/genhd.c b/block/genhd.c
index 988ba52fd331..044ff97381e3 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -519,6 +519,7 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
bdi_unregister(disk->bdi);
out_unregister_queue:
blk_unregister_queue(disk);
+ rq_qos_exit(disk->queue);
out_put_slave_dir:
kobject_put(disk->slave_dir);
out_put_holder_dir:
