Discussion:
[PATCH] jffs2: fix invocations of dbg_xattr() for dead jffs2_xattr_ref
(too old to reply)
Hou Tao
2018-10-20 11:07:53 UTC
Permalink
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 <***@huawei.com>
---
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
Boris Brezillon
2018-12-09 06:52:56 UTC
Permalink
On Sat, 20 Oct 2018 19:07:53 +0800
Post by Hou Tao
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.
---
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.
Post by Hou Tao
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));
if (!rc)
jffs2_mark_node_obsolete(c, raw);
Hou Tao
2018-12-09 06:34:59 UTC
Permalink
ping ?
Post by Hou Tao
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.
---
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));
if (!rc)
jffs2_mark_node_obsolete(c, raw);
Continue reading on narkive:
Loading...