Patchwork [v2,1/2] UBIFS: fix use of freed ubifs_orphan objects

login
register
mail settings
Submitter Adam Thomas
Date Feb. 2, 2013, 10:32 p.m.
Message ID <1359844351-5889-2-git-send-email-adamthomas1111@gmail.com>
Download mbox | patch
Permalink /patch/217705/
State Accepted
Commit 2928f0d0c5ebd6c9605c0d98207a44376387c298
Headers show

Comments

Adam Thomas - Feb. 2, 2013, 10:32 p.m.
The last orphan in the cnext list has its cnext set to NULL. Because
of that, ubifs_delete_orphan assumes that it is not on the cnext list
and frees it immediately instead of adding it to the dnext list. The
freed orphan is later modified by write_orph_node.

This can cause various inconsistencies including directory entries
that cannot be removed and this error:

UBIFS error (pid 20685): layout_cnodes: LPT out of space at LEB 14:129009 needing 17, done_ltab 1, done_lsave 1

This is a regression introduced by
"7074e5eb UBIFS: remove invalid reference to list iterator variable".

This change adds an explicit flag to ubifs_orphan indicating whether
it is pending commit.

Signed-off-by: Adam Thomas <adamthomas1111@gmail.com>
---
 fs/ubifs/orphan.c |    7 ++++++-
 fs/ubifs/ubifs.h  |    4 +++-
 2 files changed, 9 insertions(+), 2 deletions(-)
Artem Bityutskiy - Feb. 4, 2013, 10:31 a.m.
On Sat, 2013-02-02 at 22:32 +0000, Adam Thomas wrote:
> The last orphan in the cnext list has its cnext set to NULL. Because
> of that, ubifs_delete_orphan assumes that it is not on the cnext list
> and frees it immediately instead of adding it to the dnext list. The
> freed orphan is later modified by write_orph_node.
> 
> This can cause various inconsistencies including directory entries
> that cannot be removed and this error:
> 
> UBIFS error (pid 20685): layout_cnodes: LPT out of space at LEB 14:129009 needing 17, done_ltab 1, done_lsave 1
> 
> This is a regression introduced by
> "7074e5eb UBIFS: remove invalid reference to list iterator variable".
> 
> This change adds an explicit flag to ubifs_orphan indicating whether
> it is pending commit.
> 
> Signed-off-by: Adam Thomas <adamthomas1111@gmail.com>

Pushed both to linux-ubifs.git, added 'Cc: stable@vger.kernel.org'.

Patch

diff --git a/fs/ubifs/orphan.c b/fs/ubifs/orphan.c
index 769701c..8534d9c 100644
--- a/fs/ubifs/orphan.c
+++ b/fs/ubifs/orphan.c
@@ -132,7 +132,7 @@  void ubifs_delete_orphan(struct ubifs_info *c, ino_t inum)
 					(unsigned long)inum);
 				return;
 			}
-			if (o->cnext) {
+			if (o->cmt) {
 				o->dnext = c->orph_dnext;
 				c->orph_dnext = o;
 				spin_unlock(&c->orphan_lock);
@@ -172,7 +172,9 @@  int ubifs_orphan_start_commit(struct ubifs_info *c)
 	last = &c->orph_cnext;
 	list_for_each_entry(orphan, &c->orph_new, new_list) {
 		ubifs_assert(orphan->new);
+		ubifs_assert(!orphan->cmt);
 		orphan->new = 0;
+		orphan->cmt = 1;
 		*last = orphan;
 		last = &orphan->cnext;
 	}
@@ -299,7 +301,9 @@  static int write_orph_node(struct ubifs_info *c, int atomic)
 	cnext = c->orph_cnext;
 	for (i = 0; i < cnt; i++) {
 		orphan = cnext;
+		ubifs_assert(orphan->cmt);
 		orph->inos[i] = cpu_to_le64(orphan->inum);
+		orphan->cmt = 0;
 		cnext = orphan->cnext;
 		orphan->cnext = NULL;
 	}
@@ -378,6 +382,7 @@  static int consolidate(struct ubifs_info *c)
 		list_for_each_entry(orphan, &c->orph_list, list) {
 			if (orphan->new)
 				continue;
+			orphan->cmt = 1;
 			*last = orphan;
 			last = &orphan->cnext;
 			cnt += 1;
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index d133c27..c16fff7 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -904,6 +904,7 @@  struct ubifs_budget_req {
  * @dnext: next orphan to delete
  * @inum: inode number
  * @new: %1 => added since the last commit, otherwise %0
+ * @cmt: %1 => commit pending, otherwise %0
  */
 struct ubifs_orphan {
 	struct rb_node rb;
@@ -912,7 +913,8 @@  struct ubifs_orphan {
 	struct ubifs_orphan *cnext;
 	struct ubifs_orphan *dnext;
 	ino_t inum;
-	int new;
+	unsigned new:1;
+	unsigned cmt:1;
 };
 
 /**