init: Initialize noop_backing_dev_info early
Subsystems (3)
PATCH 1/1 init: Initialize noop_backing_dev_info early
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.
--- drivers/base/init.c | 2 ++ include/linux/backing-dev.h | 2 ++ mm/backing-dev.c | 11 ++--------- 3 files changed, 6 insertions(+), 9 deletions(-)
Since this bug prevents some machines from booting, I plan to push this patch to Linus unless someone objects soon... Review is welcome :).
drivers/base/init.c +2 -0
@@ -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 ();
include/linux/backing-dev.h +2 -0
@@ -119,6 +119,8 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);extern struct backing_dev_info noop_backing_dev_info; +extern int bdi_init (struct backing_dev_info *bdi); +/** * writeback_in_progress - determine whether there is writeback in progress * @wb: bdi_writeback of interest
mm/backing-dev.c +2 -9
@@ -231,20 +231,13 @@ 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);
@@ -781,7 +774,7 @@ 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;
Signature · 1 line
2.35.3
Quoted 1 line · Jan Kara
+extern int
bdi_init(struct backing_dev_info *bdi);
No need for the extern.
Otherwise looks good:
And this remind me that I really want to kill noop_backing_dev_info and just use a NULL bdi for this case eventually..
Quoted 4 lines · Christoph Hellwig
Quoted 1 line · Jan Kara
+extern int
bdi_init(struct backing_dev_info *bdi);No need for the extern.
Yes, fixed up.
Quoted 3 lines
Otherwise looks good:
Reviewed-by Christoph Hellwig <[email protected]>
Thanks for review!
Quoted 2 lines
And this remind me that I really want to kill
noop_backing_dev_infoand just use a NULL bdi for this case eventually..
Yes, I'm just not sure whether the checks for bdi / wb being NULL in lots of places will not be too annoying... But maybe you'll be able to come up with some wrappers that will make things bearable.
Honza
Signature · 2 lines
Jan Kara <[email protected]> SUSE Labs, CR
Quoted 9 lines · Jan Kara
noop_backing_dev_infois used by superblocks of various pseudofilesystems such as kdevtmpfs. After commit10e14073107d("writeback: Fixinode->i_io_listnot be protected byinode->i_lockerror") this broke because__mark_inode_dirty()started to access more fields fromnoop_backing_dev_infoand this led to crashes insidelocked_inode_to_wb_and_lock_list()called from__mark_inode_dirty(). Fix the problem by initializingnoop_backing_dev_infobefore the filesystems get mounted.
Quoted 5 lines
Fixes 10e14073107d ("writeback: Fix inode->i_io_list not be protected by inode->i_lock error")Reported-by Suzuki K Poulose <[email protected]>Reported-and-tested-by Alexandru Elisei <[email protected]>Reported-and-tested-by Guenter Roeck <[email protected]>Signed-off-by Jan Kara <[email protected]>
Works for me too. Thanks for the proper fix
Quoted 77 lines
--- drivers/base/init.c | 2 ++ include/linux/backing-dev.h | 2 ++ mm/backing-dev.c | 11 ++--------- 3 files changed, 6 insertions(+), 9 deletions(-)Since this bug prevents some machines from booting, I plan to push this patch to Linus unless someone objects soon... Review is welcome :).
drivers/base/init.c +2
-0@@ -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 ();include/linux/backing-dev.h +2
-0@@ -119,6 +119,8 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);extern struct backing_dev_info noop_backing_dev_info; +extern int bdi_init (struct backing_dev_info *bdi); +/** * writeback_in_progress - determine whether there is writeback in progress * @wb: bdi_writeback of interest mm/backing-dev.c +2
-9@@ -231,20 +231,13 @@ 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);@@ -781,7 +774,7 @@ 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;