2018-10-20 11:06:25

by Hou Tao

Subject: [PATCH] jffs2: fix invocations of dbg_xattr() for dead jffs2_xattr_ref

When jffs2_xattr_ref is dead, xref->ic or xref->xd will be invalid
because these fields will be reused as xref->ino or xref->xid,
so access xref->ic->ino or xref->xd->xid will lead to Oops.

Fix the problem by checking whether or not it is a dead xref.

Signed-off-by: Hou Tao <[email protected]>
---
fs/jffs2/xattr.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/jffs2/xattr.c b/fs/jffs2/xattr.c
index 3d40fe02b003..0c4c7891556d 100644
--- a/fs/jffs2/xattr.c
+++ b/fs/jffs2/xattr.c
@@ -550,7 +550,8 @@ static int save_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref)
ref->xseqno = xseqno;
jffs2_add_physical_node_ref(c, phys_ofs | REF_PRISTINE, PAD(sizeof(rr)), (void *)ref);

- dbg_xattr("success on saving xref (ino=%u, xid=%u)\n", ref->ic->ino, ref->xd->xid);
+ dbg_xattr("success on saving xref (ino=%u, xid=%u)\n",
+ je32_to_cpu(rr.ino), je32_to_cpu(rr.xid));

return 0;
}
@@ -1329,7 +1330,11 @@ int jffs2_garbage_collect_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_
rc = save_xattr_ref(c, ref);
if (!rc)
dbg_xattr("xref (ino=%u, xid=%u) GC'ed from %#08x to %08x\n",
- ref->ic->ino, ref->xd->xid, old_ofs, ref_offset(ref->node));
+ is_xattr_ref_dead(ref) ?
+ ref->ino : ref->ic->ino,
+ is_xattr_ref_dead(ref) ?
+ ref->xid : ref->xd->xid,
+ old_ofs, ref_offset(ref->node));
out:
if (!rc)
jffs2_mark_node_obsolete(c, raw);
--
2.16.2.dirty

2018-12-09 06:36:04

by Hou Tao

Subject: Re: [PATCH] jffs2: fix invocations of dbg_xattr() for dead jffs2_xattr_ref

ping ?

On 2018/10/20 19:07, Hou Tao wrote:
> When jffs2_xattr_ref is dead, xref->ic or xref->xd will be invalid
> because these fields will be reused as xref->ino or xref->xid,
> so access xref->ic->ino or xref->xd->xid will lead to Oops.
>
> Fix the problem by checking whether or not it is a dead xref.
>
> Signed-off-by: Hou Tao <[email protected]>
> ---
> fs/jffs2/xattr.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/fs/jffs2/xattr.c b/fs/jffs2/xattr.c
> index 3d40fe02b003..0c4c7891556d 100644
> --- a/fs/jffs2/xattr.c
> +++ b/fs/jffs2/xattr.c
> @@ -550,7 +550,8 @@ static int save_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref)
> ref->xseqno = xseqno;
> jffs2_add_physical_node_ref(c, phys_ofs | REF_PRISTINE, PAD(sizeof(rr)), (void *)ref);
>
> - dbg_xattr("success on saving xref (ino=%u, xid=%u)\n", ref->ic->ino, ref->xd->xid);
> + dbg_xattr("success on saving xref (ino=%u, xid=%u)\n",
> + je32_to_cpu(rr.ino), je32_to_cpu(rr.xid));
>
> return 0;
> }
> @@ -1329,7 +1330,11 @@ int jffs2_garbage_collect_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_
> rc = save_xattr_ref(c, ref);
> if (!rc)
> dbg_xattr("xref (ino=%u, xid=%u) GC'ed from %#08x to %08x\n",
> - ref->ic->ino, ref->xd->xid, old_ofs, ref_offset(ref->node));
> + is_xattr_ref_dead(ref) ?
> + ref->ino : ref->ic->ino,
> + is_xattr_ref_dead(ref) ?
> + ref->xid : ref->xd->xid,
> + old_ofs, ref_offset(ref->node));
> out:
> if (!rc)
> jffs2_mark_node_obsolete(c, raw);
>

2018-12-09 06:54:26

by Boris Brezillon

Subject: Re: [PATCH] jffs2: fix invocations of dbg_xattr() for dead jffs2_xattr_ref

On Sat, 20 Oct 2018 19:07:53 +0800
Hou Tao <[email protected]> wrote:

> When jffs2_xattr_ref is dead, xref->ic or xref->xd will be invalid
> because these fields will be reused as xref->ino or xref->xid,
> so access xref->ic->ino or xref->xd->xid will lead to Oops.
>
> Fix the problem by checking whether or not it is a dead xref.
>
> Signed-off-by: Hou Tao <[email protected]>
> ---
> fs/jffs2/xattr.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/fs/jffs2/xattr.c b/fs/jffs2/xattr.c
> index 3d40fe02b003..0c4c7891556d 100644
> --- a/fs/jffs2/xattr.c
> +++ b/fs/jffs2/xattr.c
> @@ -550,7 +550,8 @@ static int save_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref)
> ref->xseqno = xseqno;
> jffs2_add_physical_node_ref(c, phys_ofs | REF_PRISTINE, PAD(sizeof(rr)), (void *)ref);
>
> - dbg_xattr("success on saving xref (ino=%u, xid=%u)\n", ref->ic->ino, ref->xd->xid);
> + dbg_xattr("success on saving xref (ino=%u, xid=%u)\n",
> + je32_to_cpu(rr.ino), je32_to_cpu(rr.xid));

Nit: align the second line on the open parens (same applies to the
other chunk).

Sorry, I can't comment on the actual change. I'll let Richard look
at it.

>
> return 0;
> }
> @@ -1329,7 +1330,11 @@ int jffs2_garbage_collect_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_
> rc = save_xattr_ref(c, ref);
> if (!rc)
> dbg_xattr("xref (ino=%u, xid=%u) GC'ed from %#08x to %08x\n",
> - ref->ic->ino, ref->xd->xid, old_ofs, ref_offset(ref->node));
> + is_xattr_ref_dead(ref) ?
> + ref->ino : ref->ic->ino,
> + is_xattr_ref_dead(ref) ?
> + ref->xid : ref->xd->xid,
> + old_ofs, ref_offset(ref->node));
> out:
> if (!rc)
> jffs2_mark_node_obsolete(c, raw);

2018-12-13 21:54:40

by Richard Weinberger

Subject: Re: [PATCH] jffs2: fix invocations of dbg_xattr() for dead jffs2_xattr_ref

On Sun, Dec 9, 2018 at 7:52 AM Boris Brezillon
<[email protected]> wrote:
>
> On Sat, 20 Oct 2018 19:07:53 +0800
> Hou Tao <[email protected]> wrote:
>
> > When jffs2_xattr_ref is dead, xref->ic or xref->xd will be invalid
> > because these fields will be reused as xref->ino or xref->xid,
> > so access xref->ic->ino or xref->xd->xid will lead to Oops.
> >
> > Fix the problem by checking whether or not it is a dead xref.
> >
> > Signed-off-by: Hou Tao <[email protected]>
> > ---
> > fs/jffs2/xattr.c | 9 +++++++--
> > 1 file changed, 7 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/jffs2/xattr.c b/fs/jffs2/xattr.c
> > index 3d40fe02b003..0c4c7891556d 100644
> > --- a/fs/jffs2/xattr.c
> > +++ b/fs/jffs2/xattr.c
> > @@ -550,7 +550,8 @@ static int save_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref)
> > ref->xseqno = xseqno;
> > jffs2_add_physical_node_ref(c, phys_ofs | REF_PRISTINE, PAD(sizeof(rr)), (void *)ref);
> >
> > - dbg_xattr("success on saving xref (ino=%u, xid=%u)\n", ref->ic->ino, ref->xd->xid);
> > + dbg_xattr("success on saving xref (ino=%u, xid=%u)\n",
> > + je32_to_cpu(rr.ino), je32_to_cpu(rr.xid));
>
> Nit: align the second line on the open parens (same applies to the
> other chunk).
>
> Sorry, I can't comment on the actual change. I'll let Richard look
> at it.
>
> >
> > return 0;
> > }
> > @@ -1329,7 +1330,11 @@ int jffs2_garbage_collect_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_
> > rc = save_xattr_ref(c, ref);
> > if (!rc)
> > dbg_xattr("xref (ino=%u, xid=%u) GC'ed from %#08x to %08x\n",
> > - ref->ic->ino, ref->xd->xid, old_ofs, ref_offset(ref->node));
> > + is_xattr_ref_dead(ref) ?
> > + ref->ino : ref->ic->ino,
> > + is_xattr_ref_dead(ref) ?
> > + ref->xid : ref->xd->xid,
> > + old_ofs, ref_offset(ref->node));
> > out:
> > if (!rc)
> > jffs2_mark_node_obsolete(c, raw);
>

Since is_xattr_ref_dead() is cheap, can you please add two macros.
Something like:
static inline uint32_t xattr_ref_ino(struct jffs2_xattr_ref *ref) {
if (is_xattr_ref_dead(ref))
return ref>ino;
else
return ref->ic->ino;
}

Same for xid.
--
Thanks,
//richard

2018-12-15 13:18:29

by Hou Tao

Subject: Re: [PATCH] jffs2: fix invocations of dbg_xattr() for dead jffs2_xattr_ref

On 2018/12/14 5:53, Richard Weinberger wrote:
> On Sun, Dec 9, 2018 at 7:52 AM Boris Brezillon
> <[email protected]> wrote:
>>
>> On Sat, 20 Oct 2018 19:07:53 +0800
>> Hou Tao <[email protected]> wrote:
>>
>>> When jffs2_xattr_ref is dead, xref->ic or xref->xd will be invalid
>>> because these fields will be reused as xref->ino or xref->xid,
>>> so access xref->ic->ino or xref->xd->xid will lead to Oops.
>>>
>>> Fix the problem by checking whether or not it is a dead xref.
>>>
>>> Signed-off-by: Hou Tao <[email protected]>
>>> ---
>>> fs/jffs2/xattr.c | 9 +++++++--
>>> 1 file changed, 7 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/fs/jffs2/xattr.c b/fs/jffs2/xattr.c
>>> index 3d40fe02b003..0c4c7891556d 100644
>>> --- a/fs/jffs2/xattr.c
>>> +++ b/fs/jffs2/xattr.c
>>> @@ -550,7 +550,8 @@ static int save_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref)
>>> ref->xseqno = xseqno;
>>> jffs2_add_physical_node_ref(c, phys_ofs | REF_PRISTINE, PAD(sizeof(rr)), (void *)ref);
>>>
>>> - dbg_xattr("success on saving xref (ino=%u, xid=%u)\n", ref->ic->ino, ref->xd->xid);
>>> + dbg_xattr("success on saving xref (ino=%u, xid=%u)\n",
>>> + je32_to_cpu(rr.ino), je32_to_cpu(rr.xid));
>>
>> Nit: align the second line on the open parens (same applies to the
>> other chunk).

Thanks for pointing it out, I will fix them.

>> Sorry, I can't comment on the actual change. I'll let Richard look
>> at it.
>>
>>>
>>> return 0;
>>> }
>>> @@ -1329,7 +1330,11 @@ int jffs2_garbage_collect_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_
>>> rc = save_xattr_ref(c, ref);
>>> if (!rc)
>>> dbg_xattr("xref (ino=%u, xid=%u) GC'ed from %#08x to %08x\n",
>>> - ref->ic->ino, ref->xd->xid, old_ofs, ref_offset(ref->node));
>>> + is_xattr_ref_dead(ref) ?
>>> + ref->ino : ref->ic->ino,
>>> + is_xattr_ref_dead(ref) ?
>>> + ref->xid : ref->xd->xid,
>>> + old_ofs, ref_offset(ref->node));
>>> out:
>>> if (!rc)
>>> jffs2_mark_node_obsolete(c, raw);
>>
>
> Since is_xattr_ref_dead() is cheap, can you please add two macros.
> Something like:
> static inline uint32_t xattr_ref_ino(struct jffs2_xattr_ref *ref) {
> if (is_xattr_ref_dead(ref))
> return ref>ino;
> else
> return ref->ic->ino;
> }
>
> Same for xid.
>
Yes, there would be better, will do that.

Thanks,
Tao