On Mon, Feb 01 2016 at 11:29pm -0500, DingXiang <dingxiang@xxxxxxxxxx> wrote: > In some conditions(such as umount fs failed),origin path or origin bdev or both of the two is same > as cow's.If this happens, origin dev will be freed when get cow dev in function "dm_get_device" , > then "s->origin->dev" which used by "dm_exception_store_set_chunk_size" will be a NULL pointer. > > Here is my call trace ... > Call trace: > [<ffffffc00060b4d8>] dm_exception_store_set_chunk_size+0x6c/0x124 > [<ffffffc00060b6f8>] dm_exception_store_create+0x168/0x1c4 > [<ffffffc00060a940>] snapshot_ctr+0x168/0x5ec > [<ffffffc0005f6374>] dm_table_add_target+0x114/0x360 > [<ffffffc0005f98c8>] table_load+0x10c/0x314 > [<ffffffc0005fa480>] ctl_ioctl+0x1f8/0x4bc > [<ffffffc0005fa754>] dm_ctl_ioctl+0x10/0x20 > [<ffffffc0001ae548>] do_vfs_ioctl+0x360/0x5b4 > [<ffffffc0001ae81c>] SyS_ioctl+0x80/0x98 > > And I think the BUG https://bugzilla.redhat.com/show_bug.cgi?id=1195899 > should be the same reason. > > Signed-off-by:Ding Xiang <dingxiang@xxxxxxxxxx> Your patch wasn't correct (it couldn't handle device paths like "253:3", you also didn't check lookup_bdev's return). But I've staged the following for 4.6: https://git.kernel.org/cgit/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=for-next&id=808e62175f126de041ea1efe94b4e55511c6c119 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
