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authorDave Chinner <dchinner@redhat.com>2013-05-20 09:51:10 +1000
committerBen Myers <bpm@sgi.com>2013-05-20 14:29:34 -0500
commit52c24ad39ff02d7bd73c92eb0c926fb44984a41d (patch)
tree66a033ff6538570691dc60957564e3c4f9de38fe
parent28ca489c63e9aceed8801d2f82d731b3c9aa50f5 (diff)
downloadop-kernel-dev-52c24ad39ff02d7bd73c92eb0c926fb44984a41d.zip
op-kernel-dev-52c24ad39ff02d7bd73c92eb0c926fb44984a41d.tar.gz
xfs: Don't reference the EFI after it is freed
Checking the EFI for whether it is being released from recovery after we've already released the known active reference is a mistake worthy of a brown paper bag. Fix the (now) obvious use after free that it can cause. Reported-by: Dave Jones <davej@redhat.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
-rw-r--r--fs/xfs/xfs_extfree_item.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/xfs/xfs_extfree_item.c b/fs/xfs/xfs_extfree_item.c
index c0f3750..452920a 100644
--- a/fs/xfs/xfs_extfree_item.c
+++ b/fs/xfs/xfs_extfree_item.c
@@ -305,11 +305,12 @@ xfs_efi_release(xfs_efi_log_item_t *efip,
{
ASSERT(atomic_read(&efip->efi_next_extent) >= nextents);
if (atomic_sub_and_test(nextents, &efip->efi_next_extent)) {
- __xfs_efi_release(efip);
-
/* recovery needs us to drop the EFI reference, too */
if (test_bit(XFS_EFI_RECOVERED, &efip->efi_flags))
__xfs_efi_release(efip);
+
+ __xfs_efi_release(efip);
+ /* efip may now have been freed, do not reference it again. */
}
}
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