From: Jan Kara jack@suse.cz
[ Upstream commit 4bca7e80b6455772b4bf3f536dcbc19aac424d6a ]
noop_backing_dev_info is used by superblocks of various pseudofilesystems such as kdevtmpfs. After commit 10e14073107d ("writeback: Fix inode->i_io_list not be protected by inode->i_lock error") this broke because __mark_inode_dirty() started to access more fields from noop_backing_dev_info and this led to crashes inside locked_inode_to_wb_and_lock_list() called from __mark_inode_dirty(). Fix the problem by initializing noop_backing_dev_info before the filesystems get mounted.
Fixes: 10e14073107d ("writeback: Fix inode->i_io_list not be protected by inode->i_lock error") Reported-and-tested-by: Suzuki K Poulose suzuki.poulose@arm.com Reported-and-tested-by: Alexandru Elisei alexandru.elisei@arm.com Reported-and-tested-by: Guenter Roeck linux@roeck-us.net Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Jan Kara jack@suse.cz Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/base/init.c | 2 ++ include/linux/backing-dev.h | 2 ++ mm/backing-dev.c | 11 ++--------- 3 files changed, 6 insertions(+), 9 deletions(-)
diff --git a/drivers/base/init.c b/drivers/base/init.c index d8d0fe687111..397eb9880cec 100644 --- a/drivers/base/init.c +++ b/drivers/base/init.c @@ -8,6 +8,7 @@ #include <linux/init.h> #include <linux/memory.h> #include <linux/of.h> +#include <linux/backing-dev.h>
#include "base.h"
@@ -20,6 +21,7 @@ void __init driver_init(void) { /* These are the core pieces */ + bdi_init(&noop_backing_dev_info); devtmpfs_init(); devices_init(); buses_init(); diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 87ce24d238f3..8c2eed1b69c1 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -121,6 +121,8 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
extern struct backing_dev_info noop_backing_dev_info;
+int bdi_init(struct backing_dev_info *bdi); + /** * writeback_in_progress - determine whether there is writeback in progress * @wb: bdi_writeback of interest diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 7176af65b103..e262739a0a23 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -230,20 +230,13 @@ static __init int bdi_class_init(void) } postcore_initcall(bdi_class_init);
-static int bdi_init(struct backing_dev_info *bdi); - static int __init default_bdi_init(void) { - int err; - bdi_wq = alloc_workqueue("writeback", WQ_MEM_RECLAIM | WQ_UNBOUND | WQ_SYSFS, 0); if (!bdi_wq) return -ENOMEM; - - err = bdi_init(&noop_backing_dev_info); - - return err; + return 0; } subsys_initcall(default_bdi_init);
@@ -782,7 +775,7 @@ static void cgwb_remove_from_bdi_list(struct bdi_writeback *wb)
#endif /* CONFIG_CGROUP_WRITEBACK */
-static int bdi_init(struct backing_dev_info *bdi) +int bdi_init(struct backing_dev_info *bdi) { int ret;