This is a note to let you know that I've just added the patch titled block/rnbd-clt: Fix missing a memory free when unloading the module to the 5.10-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-rnbd-clt-fix-missing-a-memory-free-when-unload.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 24a4ecc5239cec18627076a83765b005a6d22e69 Author: Gioh Kim <gi-oh.kim@xxxxxxxxxxxxxxx> Date: Mon Apr 19 09:37:15 2021 +0200 block/rnbd-clt: Fix missing a memory free when unloading the module [ Upstream commit 12b06533104e802df73c1fbe159437c19933d6c0 ] When unloading the rnbd-clt module, it does not free a memory including the filename of the symbolic link to /sys/block/rnbdX. It is found by kmemleak as below. unreferenced object 0xffff9f1a83d3c740 (size 16): comm "bash", pid 736, jiffies 4295179665 (age 9841.310s) hex dump (first 16 bytes): 21 64 65 76 21 6e 75 6c 6c 62 30 40 62 6c 61 00 !dev!nullb0@bla. backtrace: [<0000000039f0c55e>] 0xffffffffc0456c24 [<000000001aab9513>] kernfs_fop_write+0xcf/0x1c0 [<00000000db5aa4b3>] vfs_write+0xdb/0x1d0 [<000000007a2e2207>] ksys_write+0x65/0xe0 [<00000000055e280a>] do_syscall_64+0x50/0x1b0 [<00000000c2b51831>] entry_SYSCALL_64_after_hwframe+0x49/0xbe Signed-off-by: Gioh Kim <gi-oh.kim@xxxxxxxxx> Signed-off-by: Jack Wang <jinpu.wang@xxxxxxxxx> Link: https://lore.kernel.org/r/20210419073722.15351-13-gi-oh.kim@xxxxxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/block/rnbd/rnbd-clt-sysfs.c b/drivers/block/rnbd/rnbd-clt-sysfs.c index d9dd138ca9c6..5613cd45866b 100644 --- a/drivers/block/rnbd/rnbd-clt-sysfs.c +++ b/drivers/block/rnbd/rnbd-clt-sysfs.c @@ -433,10 +433,14 @@ void rnbd_clt_remove_dev_symlink(struct rnbd_clt_dev *dev) * i.e. rnbd_clt_unmap_dev_store() leading to a sysfs warning because * of sysfs link already was removed already. */ - if (dev->blk_symlink_name && try_module_get(THIS_MODULE)) { - sysfs_remove_link(rnbd_devs_kobj, dev->blk_symlink_name); + if (dev->blk_symlink_name) { + if (try_module_get(THIS_MODULE)) { + sysfs_remove_link(rnbd_devs_kobj, dev->blk_symlink_name); + module_put(THIS_MODULE); + } + /* It should be freed always. */ kfree(dev->blk_symlink_name); - module_put(THIS_MODULE); + dev->blk_symlink_name = NULL; } }