From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
If pag cannot be allocated, the current error exit path will trip
a null pointer deference error when calling xfs_buf_hash_destroy
with a null pag. Fix this by adding a new error exit lable and
jumping to this, avoiding the hash destroy and unnecessary kmem_free
on pag.
Fixes CoverityScan CID#1397628 ("Dereference after null check")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
------------
v2: correct error exit in xfs_initialize_perag() to properly unwind
pags if error encountered.
Signed-off-by: Bill O'Donnell <billodo@xxxxxxxxxx>
---
fs/xfs/xfs_mount.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 9b9540d..67bb6f2 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -187,9 +187,10 @@ xfs_initialize_perag(
xfs_agnumber_t *maxagi)
{
xfs_agnumber_t index;
- xfs_agnumber_t first_initialised = 0;
+ xfs_agnumber_t last_valid_agindex = 0;
xfs_perag_t *pag;
int error = -ENOMEM;
+ int i;
/*
* Walk the current per-ag tree so we don't try to initialise AGs
@@ -197,17 +198,16 @@ xfs_initialize_perag(
* AGs we don't find ready for initialisation.
*/
for (index = 0; index < agcount; index++) {
+ last_valid_agindex = index;
pag = xfs_perag_get(mp, index);
if (pag) {
xfs_perag_put(pag);
continue;
}
- if (!first_initialised)
- first_initialised = index;
pag = kmem_zalloc(sizeof(*pag), KM_MAYFAIL);
if (!pag)
- goto out_unwind;
+ goto out_unwind_pags;
pag->pag_agno = index;
pag->pag_mount = mp;
spin_lock_init(&pag->pag_ici_lock);
@@ -242,8 +242,11 @@ xfs_initialize_perag(
out_unwind:
xfs_buf_hash_destroy(pag);
kmem_free(pag);
- for (; index > first_initialised; index--) {
- pag = radix_tree_delete(&mp->m_perag_tree, index);
+out_unwind_pags:
+ for (i = last_valid_agindex; i >= 0; i--) {
+ pag = radix_tree_delete(&mp->m_perag_tree, (xfs_agnumber_t)i);
+ if (!pag)
+ break;
xfs_buf_hash_destroy(pag);
kmem_free(pag);
}
--
2.9.3
--
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