From: Dan Williams Date: Mon, 7 Jun 2021 23:52:43 +0000 (-0700) Subject: libnvdimm/pmem: Fix blk_cleanup_disk() usage X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=a624eb520390cecf644a8906c982fd53b2afcc49;p=uclinux-h8%2Flinux.git libnvdimm/pmem: Fix blk_cleanup_disk() usage The queue_to_disk() helper can not be used after del_gendisk() communicate @disk via the pgmap->owner. Otherwise, queue_to_disk() returns NULL resulting in the splat below. Kernel attempted to read user page (330) - exploit attempt? (uid: 0) BUG: Kernel NULL pointer dereference on read at 0x00000330 Faulting instruction address: 0xc000000000906344 Oops: Kernel access of bad area, sig: 11 [#1] [..] NIP [c000000000906344] pmem_pagemap_cleanup+0x24/0x40 LR [c0000000004701d4] memunmap_pages+0x1b4/0x4b0 Call Trace: [c000000022cbb9c0] [c0000000009063c8] pmem_pagemap_kill+0x28/0x40 (unreliable) [c000000022cbb9e0] [c0000000004701d4] memunmap_pages+0x1b4/0x4b0 [c000000022cbba90] [c0000000008b28a0] devm_action_release+0x30/0x50 [c000000022cbbab0] [c0000000008b39c8] release_nodes+0x2f8/0x3e0 [c000000022cbbb60] [c0000000008ac440] device_release_driver_internal+0x190/0x2b0 [c000000022cbbba0] [c0000000008a8450] unbind_store+0x130/0x170 Reported-by: Sachin Sant Fixes: 87eb73b2ca7c ("nvdimm-pmem: convert to blk_alloc_disk/blk_cleanup_disk") Link: http://lore.kernel.org/r/DFB75BA8-603F-4A35-880B-C5B23EF8FA7D@linux.vnet.ibm.com Cc: Christoph Hellwig Cc: Ulf Hansson Cc: Jens Axboe Signed-off-by: Dan Williams Reviewed-by: Christoph Hellwig Tested-by: Sachin Sant Link: https://lore.kernel.org/r/162310994435.1571616.334551212901820961.stgit@dwillia2-desk3.amr.corp.intel.com [axboe: fold in compile warning fix] Signed-off-by: Jens Axboe --- diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c index 31f3c4bd6f72..1e0615b8565e 100644 --- a/drivers/nvdimm/pmem.c +++ b/drivers/nvdimm/pmem.c @@ -335,10 +335,9 @@ static const struct attribute_group *pmem_attribute_groups[] = { static void pmem_pagemap_cleanup(struct dev_pagemap *pgmap) { - struct request_queue *q = - container_of(pgmap->ref, struct request_queue, q_usage_counter); + struct pmem_device *pmem = pgmap->owner; - blk_cleanup_disk(queue_to_disk(q)); + blk_cleanup_disk(pmem->disk); } static void pmem_release_queue(void *pgmap) @@ -427,6 +426,7 @@ static int pmem_attach_disk(struct device *dev, q = disk->queue; pmem->disk = disk; + pmem->pgmap.owner = pmem; pmem->pfn_flags = PFN_DEV; pmem->pgmap.ref = &q->q_usage_counter; if (is_nd_pfn(dev)) {