The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 32b2397c1e56f33b0b1881def965bb89bd12f448 Mon Sep 17 00:00:00 2001
From: sumiyawang sumiyawang@tencent.com Date: Sun, 22 Aug 2021 19:49:09 +0800 Subject: [PATCH] libnvdimm/pmem: Fix crash triggered when I/O in-flight during unbind
There is a use after free crash when the pmem driver tears down its mapping while I/O is still inbound.
This is triggered by driver unbind, "ndctl destroy-namespace", while I/O is in flight.
Fix the sequence of blk_cleanup_queue() vs memunmap().
The crash signature is of the form:
BUG: unable to handle page fault for address: ffffc90080200000 CPU: 36 PID: 9606 Comm: systemd-udevd Call Trace: ? pmem_do_bvec+0xf9/0x3a0 ? xas_alloc+0x55/0xd0 pmem_rw_page+0x4b/0x80 bdev_read_page+0x86/0xb0 do_mpage_readpage+0x5d4/0x7a0 ? lru_cache_add+0xe/0x10 mpage_readpages+0xf9/0x1c0 ? bd_link_disk_holder+0x1a0/0x1a0 blkdev_readpages+0x1d/0x20 read_pages+0x67/0x1a0
ndctl Call Trace in vmcore: PID: 23473 TASK: ffff88c4fbbe8000 CPU: 1 COMMAND: "ndctl" __schedule schedule blk_mq_freeze_queue_wait blk_freeze_queue blk_cleanup_queue pmem_release_queue devm_action_release release_nodes devres_release_all device_release_driver_internal device_driver_detach unbind_store
Cc: stable@vger.kernel.org Signed-off-by: sumiyawang sumiyawang@tencent.com Reviewed-by: yongduan yongduan@tencent.com Link: https://lore.kernel.org/r/1629632949-14749-1-git-send-email-sumiyawang@tence... Fixes: 50f44ee7248a ("mm/devm_memremap_pages: fix final page put race") Signed-off-by: Dan Williams dan.j.williams@intel.com
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c index 1e0615b8565e..72de88ff0d30 100644 --- a/drivers/nvdimm/pmem.c +++ b/drivers/nvdimm/pmem.c @@ -450,11 +450,11 @@ static int pmem_attach_disk(struct device *dev, pmem->pfn_flags |= PFN_MAP; bb_range = pmem->pgmap.range; } else { + addr = devm_memremap(dev, pmem->phys_addr, + pmem->size, ARCH_MEMREMAP_PMEM); if (devm_add_action_or_reset(dev, pmem_release_queue, &pmem->pgmap)) return -ENOMEM; - addr = devm_memremap(dev, pmem->phys_addr, - pmem->size, ARCH_MEMREMAP_PMEM); bb_range.start = res->start; bb_range.end = res->end; }