| Message ID | 20230523074535.249802-21-hch@lst.de (mailing list archive) |
|---|---|
| State | Handled Elsewhere, archived |
| Headers | show |
| Series | [01/24] driver core: return bool from driver_probe_done | expand |
On Tue, May 23 2023 at 3:45P -0400, Christoph Hellwig <hch@lst.de> wrote: > early_lookup_bdev is supposed to only be called from the early boot > code, but dm_get_device calls it as a general fallback when lookup_bdev > fails, which is problematic because early_lookup_bdev bypasses all normal > path based permission checking, and might cause problems with certain > container environments renaming devices. > > Switch to only call early_lookup_bdev when dm is built-in and the system > state in not running yet. This means it is still available when tables > are constructed by dm-init.c from the kernel command line, but not > otherwise. > > Note that this strictly speaking changes the kernel ABI as the PARTUUID= > and PARTLABEL= style syntax is now not available during a running > systems. They never were intended for that, but this breaks things > we'll have to figure out a way to make them available again. But if > avoidable in any way I'd rather avoid that. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > drivers/md/dm-table.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c > index e997f4322a9967..c230241a76b374 100644 > --- a/drivers/md/dm-table.c > +++ b/drivers/md/dm-table.c > @@ -326,8 +326,11 @@ static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode, > /* > * Add a device to the list, or just increment the usage count if > * it's already present. > + * > + * Note: the __ref annotation is because this function can call the __init > + * marked early_lookup_bdev when called during early boot code from dm-init.c. > */ > -int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode, > +int __ref dm_get_device(struct dm_target *ti, const char *path, fmode_t mode, > struct dm_dev **result) > { > int r; > @@ -346,8 +349,10 @@ int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode, > return -EOVERFLOW; > } else { > r = lookup_bdev(path, &dev); > - if (r) > +#ifndef MODULE > + if (r && system_state < SYSTEM_RUNNING) > r = early_lookup_bdev(path, &dev); > +#endif > if (r) > return -ENODEV; > } > -- > 2.39.2 > I think/hope this will be fine: Reviewed-by: Mike Snitzer <snitzer@kernel.org>
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index e997f4322a9967..c230241a76b374 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -326,8 +326,11 @@ static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode, /* * Add a device to the list, or just increment the usage count if * it's already present. + * + * Note: the __ref annotation is because this function can call the __init + * marked early_lookup_bdev when called during early boot code from dm-init.c. */ -int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode, +int __ref dm_get_device(struct dm_target *ti, const char *path, fmode_t mode, struct dm_dev **result) { int r; @@ -346,8 +349,10 @@ int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode, return -EOVERFLOW; } else { r = lookup_bdev(path, &dev); - if (r) +#ifndef MODULE + if (r && system_state < SYSTEM_RUNNING) r = early_lookup_bdev(path, &dev); +#endif if (r) return -ENODEV; }
early_lookup_bdev is supposed to only be called from the early boot code, but dm_get_device calls it as a general fallback when lookup_bdev fails, which is problematic because early_lookup_bdev bypasses all normal path based permission checking, and might cause problems with certain container environments renaming devices. Switch to only call early_lookup_bdev when dm is built-in and the system state in not running yet. This means it is still available when tables are constructed by dm-init.c from the kernel command line, but not otherwise. Note that this strictly speaking changes the kernel ABI as the PARTUUID= and PARTLABEL= style syntax is now not available during a running systems. They never were intended for that, but this breaks things we'll have to figure out a way to make them available again. But if avoidable in any way I'd rather avoid that. Signed-off-by: Christoph Hellwig <hch@lst.de> --- drivers/md/dm-table.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)