Hi Alasdair, This is an updated patch-set to fix bugs in device removal corner-cases, replacing the previous version found in: https://patchwork.kernel.org/patch/83995/ Please review and take this patch-set instead. This patch-set can be applied on top of 2.6.35-rc1 + your NEXT_PATCHES. The patch-set contains 3 patches: The 3rd patch is basically same as the one I posted before. The 1st patch is a new patch fixing possible NULL pointer dereference. The 2nd patch fixes a deadlock, which is introduced by the 3rd patch. The deadlock is AB-BA deadlock between dm_hash_remove_all(), which waits for md->holders to be 0 with _hash_lock held, and other ioctls which waits for _hash_lock with md->holders held (e.g. table_status(), table_load()): CPU0 CPU1 ------------------------------------------------------------------ dm_hash_remove_all() down_write(_hash_lock) table_status() md = find_device() dm_get(md) dm_get_live_or_inactive_table() dm_get_inactive_table() down_write(_hash_lock) dm_destroy(md) while (md->holders) msleep(1) To fix this deadlock problem, this patch-set changes dm_hash_remove_all() to release _hash_lock when removing a mapped_device, then, take _hash_lock and start over again. Summary of the patch-set: 1/3: dm: prevent access to md being deleted 2/3: dm: release _hash_lock when removing device in remove_all 3/3: dm: separate device deletion from dm_put() drivers/md/dm-ioctl.c | 61 ++++++++++++++++++++++++++++---------------------- drivers/md/dm.c | 60 ++++++++++++++++++++++++++++++++++++------------- drivers/md/dm.h | 5 ++++ 3 files changed, 84 insertions(+), 42 deletions(-) Thanks, Kiyoshi Ueda -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
