From: Gioh Kim gi-oh.kim@cloud.ionos.com
[ 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@ionos.com Signed-off-by: Jack Wang jinpu.wang@ionos.com Link: https://lore.kernel.org/r/20210419073722.15351-13-gi-oh.kim@ionos.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/block/rnbd/rnbd-clt-sysfs.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/block/rnbd/rnbd-clt-sysfs.c b/drivers/block/rnbd/rnbd-clt-sysfs.c index d4aa6bfc9555..526c77cd7a50 100644 --- a/drivers/block/rnbd/rnbd-clt-sysfs.c +++ b/drivers/block/rnbd/rnbd-clt-sysfs.c @@ -432,10 +432,14 @@ 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; } }