On Sun, Mar 22, 2020 at 12:23:14PM +0100, Domenico Andreoli wrote:
> On Sun, Mar 22, 2020 at 08:14:21AM +0100, Rafael J. Wysocki wrote:
> > On Wednesday, March 4, 2020 6:06:46 PM CET Domenico Andreoli wrote:
> > > From: Domenico Andreoli <domenico.andreoli@xxxxxxxxx>
> > >
> > > It turns out that there is one use case for programs being able to
> > > write to swap devices, and that is the userspace hibernation code.
> > >
> > > Quick fix: disable the S_SWAPFILE check if hibernation is configured.
> > >
> > > Fixes: dc617f29dbe5 ("vfs: don't allow writes to swap files")
> > > Reported-by: Domenico Andreoli <domenico.andreoli@xxxxxxxxx>
> > > Reported-by: Marian Klein <mkleinsoft@xxxxxxxxx>
> > > Signed-off-by: Domenico Andreoli <domenico.andreoli@xxxxxxxxx>
> > >
> > > v2:
> > > - use hibernation_available() instead of IS_ENABLED(CONFIG_HIBERNATE)
> > > - make Fixes: point to the right commit
> >
> > This looks OK to me.
> >
> > Has it been taken care of already, or am I expected to apply it?
>
> I don't know who is supposed to take it, I did not receive any notification.
Hmmm. I thought it had been picked up by akpm (see "[alternative-merged]
vfs-partially-revert-dont-allow-writes-to-swap-files.patch removed from
-mm tree" from 5 March), but it's not in mmotm now, so I'll put this in my
vfs tree for 5.7.
Also, since apparently my previous RVB apparently never made it to the
internet,
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
--D
> >
> > > ---
> > > fs/block_dev.c | 4 +++-
> > > 1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > Index: b/fs/block_dev.c
> > > ===================================================================
> > > --- a/fs/block_dev.c
> > > +++ b/fs/block_dev.c
> > > @@ -34,6 +34,7 @@
> > > #include <linux/task_io_accounting_ops.h>
> > > #include <linux/falloc.h>
> > > #include <linux/uaccess.h>
> > > +#include <linux/suspend.h>
> > > #include "internal.h"
> > >
> > > struct bdev_inode {
> > > @@ -2001,7 +2002,8 @@ ssize_t blkdev_write_iter(struct kiocb *
> > > if (bdev_read_only(I_BDEV(bd_inode)))
> > > return -EPERM;
> > >
> > > - if (IS_SWAPFILE(bd_inode))
> > > + /* uswsusp needs write permission to the swap */
> > > + if (IS_SWAPFILE(bd_inode) && !hibernation_available())
> > > return -ETXTBSY;
> > >
> > > if (!iov_iter_count(from))
> > >
> >
> >
> >
> >
>
> --
> rsa4096: 3B10 0CA1 8674 ACBA B4FE FCD2 CE5B CF17 9960 DE13
> ed25519: FFB4 0CC3 7F2E 091D F7DA 356E CC79 2832 ED38 CB05
