| Message ID | 20220615214815.6901-1-jack@suse.cz (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | init: Initialize noop_backing_dev_info early | expand |
On Wed, Jun 15, 2022 at 11:48:15PM +0200, Jan Kara wrote: > +extern int bdi_init(struct backing_dev_info *bdi); No need for the extern. Otherwise looks good: Reviewed-by: Christoph Hellwig <hch@lst.de> And this remind me that I really want to kill noop_backing_dev_info and just use a NULL bdi for this case eventually..
On 15/06/2022 22:48, Jan Kara wrote: > 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-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> > Signed-off-by: Jan Kara <jack@suse.cz> Works for me too. Thanks for the proper fix Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com> > --- > 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 :). > > 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 2bd073fa6bb5..f0baef68f90f 100644 > --- a/include/linux/backing-dev.h > +++ b/include/linux/backing-dev.h > @@ -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 > diff --git a/mm/backing-dev.c b/mm/backing-dev.c > index ff60bd7d74e0..95550b8fa7fe 100644 > --- a/mm/backing-dev.c > +++ b/mm/backing-dev.c > @@ -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; >
On Wed 15-06-22 23:08:22, Christoph Hellwig wrote: > On Wed, Jun 15, 2022 at 11:48:15PM +0200, Jan Kara wrote: > > +extern int bdi_init(struct backing_dev_info *bdi); > > No need for the extern. Yes, fixed up. > Otherwise looks good: > > Reviewed-by: Christoph Hellwig <hch@lst.de> Thanks for review! > And this remind me that I really want to kill noop_backing_dev_info > and 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
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 2bd073fa6bb5..f0baef68f90f 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -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 diff --git a/mm/backing-dev.c b/mm/backing-dev.c index ff60bd7d74e0..95550b8fa7fe 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -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;
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-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> Signed-off-by: Jan Kara <jack@suse.cz> --- 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 :).