From cf387d9644d8c78721cf9b77af9f67bb5b04da16 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Tue, 10 Sep 2019 11:58:25 +0530 Subject: libnvdimm/altmap: Track namespace boundaries in altmap With PFN_MODE_PMEM namespace, the memmap area is allocated from the device area. Some architectures map the memmap area with large page size. On architectures like ppc64, 16MB page for memap mapping can map 262144 pfns. This maps a namespace size of 16G. When populating memmap region with 16MB page from the device area, make sure the allocated space is not used to map resources outside this namespace. Such usage of device area will prevent a namespace destroy. Add resource end pnf in altmap and use that to check if the memmap area allocation can map pfn outside the namespace. On ppc64 in such case we fallback to allocation from memory. This fix kernel crash reported below: [ 132.034989] WARNING: CPU: 13 PID: 13719 at mm/memremap.c:133 devm_memremap_pages_release+0x2d8/0x2e0 [ 133.464754] BUG: Unable to handle kernel data access at 0xc00c00010b204000 [ 133.464760] Faulting instruction address: 0xc00000000007580c [ 133.464766] Oops: Kernel access of bad area, sig: 11 [#1] [ 133.464771] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries ..... [ 133.464901] NIP [c00000000007580c] vmemmap_free+0x2ac/0x3d0 [ 133.464906] LR [c0000000000757f8] vmemmap_free+0x298/0x3d0 [ 133.464910] Call Trace: [ 133.464914] [c000007cbfd0f7b0] [c0000000000757f8] vmemmap_free+0x298/0x3d0 (unreliable) [ 133.464921] [c000007cbfd0f8d0] [c000000000370a44] section_deactivate+0x1a4/0x240 [ 133.464928] [c000007cbfd0f980] [c000000000386270] __remove_pages+0x3a0/0x590 [ 133.464935] [c000007cbfd0fa50] [c000000000074158] arch_remove_memory+0x88/0x160 [ 133.464942] [c000007cbfd0fae0] [c0000000003be8c0] devm_memremap_pages_release+0x150/0x2e0 [ 133.464949] [c000007cbfd0fb70] [c000000000738ea0] devm_action_release+0x30/0x50 [ 133.464955] [c000007cbfd0fb90] [c00000000073a5a4] release_nodes+0x344/0x400 [ 133.464961] [c000007cbfd0fc40] [c00000000073378c] device_release_driver_internal+0x15c/0x250 [ 133.464968] [c000007cbfd0fc80] [c00000000072fd14] unbind_store+0x104/0x110 [ 133.464973] [c000007cbfd0fcd0] [c00000000072ee24] drv_attr_store+0x44/0x70 [ 133.464981] [c000007cbfd0fcf0] [c0000000004a32bc] sysfs_kf_write+0x6c/0xa0 [ 133.464987] [c000007cbfd0fd10] [c0000000004a1dfc] kernfs_fop_write+0x17c/0x250 [ 133.464993] [c000007cbfd0fd60] [c0000000003c348c] __vfs_write+0x3c/0x70 [ 133.464999] [c000007cbfd0fd80] [c0000000003c75d0] vfs_write+0xd0/0x250 djbw: Aneesh notes that this crash can likely be triggered in any kernel that supports 'papr_scm', so flagging that commit for -stable consideration. Fixes: b5beae5e224f ("powerpc/pseries: Add driver for PAPR SCM regions") Cc: Reported-by: Sachin Sant Signed-off-by: Aneesh Kumar K.V Reviewed-by: Pankaj Gupta Tested-by: Santosh Sivaraj Reviewed-by: Johannes Thumshirn Link: https://lore.kernel.org/r/20190910062826.10041-1-aneesh.kumar@linux.ibm.com Signed-off-by: Dan Williams --- drivers/nvdimm/pfn_devs.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/nvdimm') diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c index 934cdcaaae97..80c7992bc538 100644 --- a/drivers/nvdimm/pfn_devs.c +++ b/drivers/nvdimm/pfn_devs.c @@ -672,9 +672,11 @@ static int __nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap) struct nd_namespace_common *ndns = nd_pfn->ndns; struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev); resource_size_t base = nsio->res.start + start_pad; + resource_size_t end = nsio->res.end - end_trunc; struct vmem_altmap __altmap = { .base_pfn = init_altmap_base(base), .reserve = init_altmap_reserve(base), + .end_pfn = PHYS_PFN(end), }; memcpy(res, &nsio->res, sizeof(*res)); -- cgit