From ab68b6e5db29abcd20c0c7b12a8c2fa570031c8b Mon Sep 17 00:00:00 2001 From: Tim Chase Date: Mon, 24 Jun 2013 22:03:56 -0500 Subject: [PATCH] Fix zfs_sb_teardown/zfs_resume_fs NULL dereference Fix a pair of conditions in which a concurrent umount can cause NULL pointer dereferences: * zfs_sb_teardown - prevent a NULL dereference by not calling dmu_objset_pool with a null z_os. * zfs_resume_fs - don't try to unmount with a null z_os. This change makes the ZoL code more consistent with both Illumos and FreeBSD. Signed-off-by: Brian Behlendorf Closes #1543 --- module/zfs/zfs_vfsops.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/module/zfs/zfs_vfsops.c b/module/zfs/zfs_vfsops.c index e618f2b..602c332 100644 --- a/module/zfs/zfs_vfsops.c +++ b/module/zfs/zfs_vfsops.c @@ -1056,10 +1056,12 @@ zfs_sb_teardown(zfs_sb_t *zsb, boolean_t unmounting) } /* - * Drain the iput_taskq to ensure all active references to the + * If someone has not already unmounted this file system, + * drain the iput_taskq to ensure all active references to the * zfs_sb_t have been handled only then can it be safely destroyed. */ - taskq_wait(dsl_pool_iput_taskq(dmu_objset_pool(zsb->z_os))); + if (zsb->z_os) + taskq_wait(dsl_pool_iput_taskq(dmu_objset_pool(zsb->z_os))); /* * Close the zil. NB: Can't close the zil while zfs_inactive @@ -1480,10 +1482,11 @@ bail: if (err) { /* - * Since we couldn't reopen zfs_sb_t, force - * unmount this file system. + * Since we couldn't reopen zfs_sb_t or, setup the + * sa framework, force unmount this file system. */ - (void) zfs_umount(zsb->z_sb); + if (zsb->z_os) + (void) zfs_umount(zsb->z_sb); } return (err); } -- 1.8.3.1