module_is_live function is only defined when CONFIG_MODULES is enabled.
Use try_module_get instead to check whether the module is being removed.
When module unload and manuall unmapping is happening in parallel, we can
try removing the symlink twice: rnbd_client_exit vs. rnbd_clt_unmap_dev_store.
This is probably not the best way to deal with this race in general, but for
now this fixes the compilation issue when CONFIG_MODULES is disabled and has
no functional impact. Regression tests passed.
Fixes: 1eb54f8f5dd8 ("block/rnbd: client: sysfs interface functions")
Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Suggested-by: Guoqing Jiang <guoqing.jiang@xxxxxxxxxxxxxxx>
Signed-off-by: Danil Kipnis <danil.kipnis@xxxxxxxxxxxxxxx>
Acked-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
---
v1->v2 Fix format of the "Fixes:" line
Add Acked-by Randy Runlap <rdunlap@xxxxxxxxxxxxx>
drivers/block/rnbd/rnbd-clt-sysfs.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/block/rnbd/rnbd-clt-sysfs.c b/drivers/block/rnbd/rnbd-clt-sysfs.c
index a4508fcc7ffe..73d7cb40abb3 100644
--- a/drivers/block/rnbd/rnbd-clt-sysfs.c
+++ b/drivers/block/rnbd/rnbd-clt-sysfs.c
@@ -428,12 +428,14 @@ static struct attribute *rnbd_dev_attrs[] = {
void rnbd_clt_remove_dev_symlink(struct rnbd_clt_dev *dev)
{
/*
- * The module_is_live() check is crucial and helps to avoid annoying
- * sysfs warning raised in sysfs_remove_link(), when the whole sysfs
- * path was just removed, see rnbd_close_sessions().
+ * The module unload rnbd_client_exit path is racing with unmapping of the
+ * last single device from the sysfs manually i.e. rnbd_clt_unmap_dev_store()
+ * leading to a sysfs warning because of sysfs link already was removed already.
*/
- if (strlen(dev->blk_symlink_name) && module_is_live(THIS_MODULE))
+ if (strlen(dev->blk_symlink_name) && try_module_get(THIS_MODULE)) {
sysfs_remove_link(rnbd_devs_kobj, dev->blk_symlink_name);
+ module_put(THIS_MODULE);
+ }
}
static struct kobj_type rnbd_dev_ktype = {
--
2.25.1
