* [PATCH] ovl: fix oops in ovl_indexdir_cleanup() with nfs_export=on
@ 2020-06-21 6:37 Amir Goldstein
2020-07-06 12:15 ` Amir Goldstein
2020-07-14 14:23 ` Miklos Szeredi
0 siblings, 2 replies; 4+ messages in thread
From: Amir Goldstein @ 2020-06-21 6:37 UTC (permalink / raw)
To: Miklos Szeredi; +Cc: Murphy Zhou, linux-unionfs
Mounting with nfs_export=on, xfstests overlay/031 triggers a kernel panic
since v5.8-rc1 overlayfs updates.
overlayfs: orphan index entry (index/00fb1..., ftype=4000, nlink=2)
BUG: kernel NULL pointer dereference, address: 0000000000000030
RIP: 0010:ovl_cleanup_and_whiteout+0x28/0x220 [overlay]
Bisect point at commit c21c839b8448 ("ovl: whiteout inode sharing")
Minimal reproducer:
--------------------------------------------------
rm -rf l u w m
mkdir -p l u w m
mkdir -p l/testdir
touch l/testdir/testfile
mount -t overlay -o lowerdir=l,upperdir=u,workdir=w,nfs_export=on overlay m
echo 1 > m/testdir/testfile
umount m
rm -rf u/testdir
mount -t overlay -o lowerdir=l,upperdir=u,workdir=w,nfs_export=on overlay m
umount m
--------------------------------------------------
When mount with nfs_export=on, and fail to verify an orphan index, we're
cleaning this index from indexdir by calling ovl_cleanup_and_whiteout().
This dereferences ofs->workdir, that was earlier set to NULL.
The design was that ovl->workdir will point at ovl->indexdir, but we are
assigning ofs->indexdir to ofs->workdir only after ovl_indexdir_cleanup().
There is no reason not to do it sooner, because once we get success from
ofs->indexdir = ovl_workdir_create(... there is no turning back.
Reported-and-tested-by: Murphy Zhou <jencce.kernel@gmail.com>
Fixes: commit c21c839b8448 ("ovl: whiteout inode sharing")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
fs/overlayfs/super.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 91476bc422f9..15939ab39c1c 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1354,6 +1354,12 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs,
ofs->indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true);
if (ofs->indexdir) {
+ /* index dir will act also as workdir */
+ iput(ofs->workdir_trap);
+ ofs->workdir_trap = NULL;
+ dput(ofs->workdir);
+ ofs->workdir = dget(ofs->indexdir);
+
err = ovl_setup_trap(sb, ofs->indexdir, &ofs->indexdir_trap,
"indexdir");
if (err)
@@ -1843,20 +1849,12 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
sb->s_flags |= SB_RDONLY;
if (!(ovl_force_readonly(ofs)) && ofs->config.index) {
- /* index dir will act also as workdir */
- dput(ofs->workdir);
- ofs->workdir = NULL;
- iput(ofs->workdir_trap);
- ofs->workdir_trap = NULL;
-
err = ovl_get_indexdir(sb, ofs, oe, &upperpath);
if (err)
goto out_free_oe;
/* Force r/o mount with no index dir */
- if (ofs->indexdir)
- ofs->workdir = dget(ofs->indexdir);
- else
+ if (!ofs->indexdir)
sb->s_flags |= SB_RDONLY;
}
--
2.17.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] ovl: fix oops in ovl_indexdir_cleanup() with nfs_export=on
2020-06-21 6:37 [PATCH] ovl: fix oops in ovl_indexdir_cleanup() with nfs_export=on Amir Goldstein
@ 2020-07-06 12:15 ` Amir Goldstein
2020-07-13 6:06 ` Murphy Zhou
2020-07-14 14:23 ` Miklos Szeredi
1 sibling, 1 reply; 4+ messages in thread
From: Amir Goldstein @ 2020-07-06 12:15 UTC (permalink / raw)
To: Miklos Szeredi; +Cc: Murphy Zhou, overlayfs
On Sun, Jun 21, 2020 at 9:38 AM Amir Goldstein <amir73il@gmail.com> wrote:
>
> Mounting with nfs_export=on, xfstests overlay/031 triggers a kernel panic
> since v5.8-rc1 overlayfs updates.
Ping.
This is a kernel OOPS regression in v5.8-rc1.
Push tested branch ovl-fixes based on v5.8-rc3 with this change.
It contains two other non-critical fixes, which are pretty obvious,
so you may want to consider taking them as well.
Thanks,
Amir.
>
> overlayfs: orphan index entry (index/00fb1..., ftype=4000, nlink=2)
> BUG: kernel NULL pointer dereference, address: 0000000000000030
> RIP: 0010:ovl_cleanup_and_whiteout+0x28/0x220 [overlay]
>
> Bisect point at commit c21c839b8448 ("ovl: whiteout inode sharing")
>
> Minimal reproducer:
> --------------------------------------------------
> rm -rf l u w m
> mkdir -p l u w m
> mkdir -p l/testdir
> touch l/testdir/testfile
> mount -t overlay -o lowerdir=l,upperdir=u,workdir=w,nfs_export=on overlay m
> echo 1 > m/testdir/testfile
> umount m
> rm -rf u/testdir
> mount -t overlay -o lowerdir=l,upperdir=u,workdir=w,nfs_export=on overlay m
> umount m
> --------------------------------------------------
>
> When mount with nfs_export=on, and fail to verify an orphan index, we're
> cleaning this index from indexdir by calling ovl_cleanup_and_whiteout().
> This dereferences ofs->workdir, that was earlier set to NULL.
>
> The design was that ovl->workdir will point at ovl->indexdir, but we are
> assigning ofs->indexdir to ofs->workdir only after ovl_indexdir_cleanup().
> There is no reason not to do it sooner, because once we get success from
> ofs->indexdir = ovl_workdir_create(... there is no turning back.
>
> Reported-and-tested-by: Murphy Zhou <jencce.kernel@gmail.com>
> Fixes: commit c21c839b8448 ("ovl: whiteout inode sharing")
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> ---
> fs/overlayfs/super.c | 16 +++++++---------
> 1 file changed, 7 insertions(+), 9 deletions(-)
>
> diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
> index 91476bc422f9..15939ab39c1c 100644
> --- a/fs/overlayfs/super.c
> +++ b/fs/overlayfs/super.c
> @@ -1354,6 +1354,12 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs,
>
> ofs->indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true);
> if (ofs->indexdir) {
> + /* index dir will act also as workdir */
> + iput(ofs->workdir_trap);
> + ofs->workdir_trap = NULL;
> + dput(ofs->workdir);
> + ofs->workdir = dget(ofs->indexdir);
> +
> err = ovl_setup_trap(sb, ofs->indexdir, &ofs->indexdir_trap,
> "indexdir");
> if (err)
> @@ -1843,20 +1849,12 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
> sb->s_flags |= SB_RDONLY;
>
> if (!(ovl_force_readonly(ofs)) && ofs->config.index) {
> - /* index dir will act also as workdir */
> - dput(ofs->workdir);
> - ofs->workdir = NULL;
> - iput(ofs->workdir_trap);
> - ofs->workdir_trap = NULL;
> -
> err = ovl_get_indexdir(sb, ofs, oe, &upperpath);
> if (err)
> goto out_free_oe;
>
> /* Force r/o mount with no index dir */
> - if (ofs->indexdir)
> - ofs->workdir = dget(ofs->indexdir);
> - else
> + if (!ofs->indexdir)
> sb->s_flags |= SB_RDONLY;
> }
>
> --
> 2.17.1
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] ovl: fix oops in ovl_indexdir_cleanup() with nfs_export=on
2020-07-06 12:15 ` Amir Goldstein
@ 2020-07-13 6:06 ` Murphy Zhou
0 siblings, 0 replies; 4+ messages in thread
From: Murphy Zhou @ 2020-07-13 6:06 UTC (permalink / raw)
To: Amir Goldstein, Miklos Szeredi; +Cc: Miklos Szeredi, Murphy Zhou, overlayfs
Copying Miklos' another email.
On Mon, Jul 06, 2020 at 03:15:06PM +0300, Amir Goldstein wrote:
> On Sun, Jun 21, 2020 at 9:38 AM Amir Goldstein <amir73il@gmail.com> wrote:
> >
> > Mounting with nfs_export=on, xfstests overlay/031 triggers a kernel panic
> > since v5.8-rc1 overlayfs updates.
>
> Ping.
>
> This is a kernel OOPS regression in v5.8-rc1.
>
> Push tested branch ovl-fixes based on v5.8-rc3 with this change.
> It contains two other non-critical fixes, which are pretty obvious,
> so you may want to consider taking them as well.
>
> Thanks,
> Amir.
>
> >
> > overlayfs: orphan index entry (index/00fb1..., ftype=4000, nlink=2)
> > BUG: kernel NULL pointer dereference, address: 0000000000000030
> > RIP: 0010:ovl_cleanup_and_whiteout+0x28/0x220 [overlay]
> >
> > Bisect point at commit c21c839b8448 ("ovl: whiteout inode sharing")
> >
> > Minimal reproducer:
> > --------------------------------------------------
> > rm -rf l u w m
> > mkdir -p l u w m
> > mkdir -p l/testdir
> > touch l/testdir/testfile
> > mount -t overlay -o lowerdir=l,upperdir=u,workdir=w,nfs_export=on overlay m
> > echo 1 > m/testdir/testfile
> > umount m
> > rm -rf u/testdir
> > mount -t overlay -o lowerdir=l,upperdir=u,workdir=w,nfs_export=on overlay m
> > umount m
> > --------------------------------------------------
> >
> > When mount with nfs_export=on, and fail to verify an orphan index, we're
> > cleaning this index from indexdir by calling ovl_cleanup_and_whiteout().
> > This dereferences ofs->workdir, that was earlier set to NULL.
> >
> > The design was that ovl->workdir will point at ovl->indexdir, but we are
> > assigning ofs->indexdir to ofs->workdir only after ovl_indexdir_cleanup().
> > There is no reason not to do it sooner, because once we get success from
> > ofs->indexdir = ovl_workdir_create(... there is no turning back.
> >
> > Reported-and-tested-by: Murphy Zhou <jencce.kernel@gmail.com>
> > Fixes: commit c21c839b8448 ("ovl: whiteout inode sharing")
> > Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> > ---
> > fs/overlayfs/super.c | 16 +++++++---------
> > 1 file changed, 7 insertions(+), 9 deletions(-)
> >
> > diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
> > index 91476bc422f9..15939ab39c1c 100644
> > --- a/fs/overlayfs/super.c
> > +++ b/fs/overlayfs/super.c
> > @@ -1354,6 +1354,12 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs,
> >
> > ofs->indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true);
> > if (ofs->indexdir) {
> > + /* index dir will act also as workdir */
> > + iput(ofs->workdir_trap);
> > + ofs->workdir_trap = NULL;
> > + dput(ofs->workdir);
> > + ofs->workdir = dget(ofs->indexdir);
> > +
> > err = ovl_setup_trap(sb, ofs->indexdir, &ofs->indexdir_trap,
> > "indexdir");
> > if (err)
> > @@ -1843,20 +1849,12 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
> > sb->s_flags |= SB_RDONLY;
> >
> > if (!(ovl_force_readonly(ofs)) && ofs->config.index) {
> > - /* index dir will act also as workdir */
> > - dput(ofs->workdir);
> > - ofs->workdir = NULL;
> > - iput(ofs->workdir_trap);
> > - ofs->workdir_trap = NULL;
> > -
> > err = ovl_get_indexdir(sb, ofs, oe, &upperpath);
> > if (err)
> > goto out_free_oe;
> >
> > /* Force r/o mount with no index dir */
> > - if (ofs->indexdir)
> > - ofs->workdir = dget(ofs->indexdir);
> > - else
> > + if (!ofs->indexdir)
> > sb->s_flags |= SB_RDONLY;
> > }
> >
> > --
> > 2.17.1
> >
--
Murphy
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] ovl: fix oops in ovl_indexdir_cleanup() with nfs_export=on
2020-06-21 6:37 [PATCH] ovl: fix oops in ovl_indexdir_cleanup() with nfs_export=on Amir Goldstein
2020-07-06 12:15 ` Amir Goldstein
@ 2020-07-14 14:23 ` Miklos Szeredi
1 sibling, 0 replies; 4+ messages in thread
From: Miklos Szeredi @ 2020-07-14 14:23 UTC (permalink / raw)
To: Amir Goldstein; +Cc: Murphy Zhou, overlayfs
On Sun, Jun 21, 2020 at 8:38 AM Amir Goldstein <amir73il@gmail.com> wrote:
>
> Mounting with nfs_export=on, xfstests overlay/031 triggers a kernel panic
> since v5.8-rc1 overlayfs updates.
>
> overlayfs: orphan index entry (index/00fb1..., ftype=4000, nlink=2)
> BUG: kernel NULL pointer dereference, address: 0000000000000030
> RIP: 0010:ovl_cleanup_and_whiteout+0x28/0x220 [overlay]
>
> Bisect point at commit c21c839b8448 ("ovl: whiteout inode sharing")
>
> Minimal reproducer:
> --------------------------------------------------
> rm -rf l u w m
> mkdir -p l u w m
> mkdir -p l/testdir
> touch l/testdir/testfile
> mount -t overlay -o lowerdir=l,upperdir=u,workdir=w,nfs_export=on overlay m
> echo 1 > m/testdir/testfile
> umount m
> rm -rf u/testdir
> mount -t overlay -o lowerdir=l,upperdir=u,workdir=w,nfs_export=on overlay m
> umount m
> --------------------------------------------------
>
> When mount with nfs_export=on, and fail to verify an orphan index, we're
> cleaning this index from indexdir by calling ovl_cleanup_and_whiteout().
> This dereferences ofs->workdir, that was earlier set to NULL.
>
> The design was that ovl->workdir will point at ovl->indexdir, but we are
> assigning ofs->indexdir to ofs->workdir only after ovl_indexdir_cleanup().
> There is no reason not to do it sooner, because once we get success from
> ofs->indexdir = ovl_workdir_create(... there is no turning back.
>
> Reported-and-tested-by: Murphy Zhou <jencce.kernel@gmail.com>
> Fixes: commit c21c839b8448 ("ovl: whiteout inode sharing")
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Thanks, applied.
Miklos
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-06-21 6:37 [PATCH] ovl: fix oops in ovl_indexdir_cleanup() with nfs_export=on Amir Goldstein
2020-07-06 12:15 ` Amir Goldstein
2020-07-13 6:06 ` Murphy Zhou
2020-07-14 14:23 ` Miklos Szeredi
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