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authorAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>2019-09-10 11:58:25 +0530
committerDan Williams <dan.j.williams@intel.com>2019-09-24 10:24:12 -0700
commitcf387d9644d8c78721cf9b77af9f67bb5b04da16 (patch)
treeaa1110a9f9564d34c41cb553195b1b1580b0e9ad /arch/powerpc
parent86aa66687442ef45909ff9814b82b4d2bb892294 (diff)
downloadblackbird-op-linux-cf387d9644d8c78721cf9b77af9f67bb5b04da16.tar.gz
blackbird-op-linux-cf387d9644d8c78721cf9b77af9f67bb5b04da16.zip
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: <stable@vger.kernel.org> Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Reviewed-by: Pankaj Gupta <pagupta@redhat.com> Tested-by: Santosh Sivaraj <santosh@fossix.org> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Link: https://lore.kernel.org/r/20190910062826.10041-1-aneesh.kumar@linux.ibm.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/mm/init_64.c17
1 files changed, 16 insertions, 1 deletions
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index a44f6281ca3a..4e08246acd79 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -172,6 +172,21 @@ static __meminit void vmemmap_list_populate(unsigned long phys,
vmemmap_list = vmem_back;
}
+static bool altmap_cross_boundary(struct vmem_altmap *altmap, unsigned long start,
+ unsigned long page_size)
+{
+ unsigned long nr_pfn = page_size / sizeof(struct page);
+ unsigned long start_pfn = page_to_pfn((struct page *)start);
+
+ if ((start_pfn + nr_pfn) > altmap->end_pfn)
+ return true;
+
+ if (start_pfn < altmap->base_pfn)
+ return true;
+
+ return false;
+}
+
int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
struct vmem_altmap *altmap)
{
@@ -194,7 +209,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
* fail due to alignment issues when using 16MB hugepages, so
* fall back to system memory if the altmap allocation fail.
*/
- if (altmap) {
+ if (altmap && !altmap_cross_boundary(altmap, start, page_size)) {
p = altmap_alloc_block_buf(page_size, altmap);
if (!p)
pr_debug("altmap block allocation failed, falling back to system memory");
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