From 0207df4fa1a869281ddbf72db6203dbf036b3e1a Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin Date: Fri, 17 Aug 2018 15:47:04 -0700 Subject: kernel/memremap, kasan: make ZONE_DEVICE with work with KASAN KASAN learns about hotadded memory via the memory hotplug notifier. devm_memremap_pages() intentionally skips calling memory hotplug notifiers. So KASAN doesn't know anything about new memory added by devm_memremap_pages(). This causes a crash when KASAN tries to access non-existent shadow memory: BUG: unable to handle kernel paging request at ffffed0078000000 RIP: 0010:check_memory_region+0x82/0x1e0 Call Trace: memcpy+0x1f/0x50 pmem_do_bvec+0x163/0x720 pmem_make_request+0x305/0xac0 generic_make_request+0x54f/0xcf0 submit_bio+0x9c/0x370 submit_bh_wbc+0x4c7/0x700 block_read_full_page+0x5ef/0x870 do_read_cache_page+0x2b8/0xb30 read_dev_sector+0xbd/0x3f0 read_lba.isra.0+0x277/0x670 efi_partition+0x41a/0x18f0 check_partition+0x30d/0x5e9 rescan_partitions+0x18c/0x840 __blkdev_get+0x859/0x1060 blkdev_get+0x23f/0x810 __device_add_disk+0x9c8/0xde0 pmem_attach_disk+0x9a8/0xf50 nvdimm_bus_probe+0xf3/0x3c0 driver_probe_device+0x493/0xbd0 bus_for_each_drv+0x118/0x1b0 __device_attach+0x1cd/0x2b0 bus_probe_device+0x1ac/0x260 device_add+0x90d/0x1380 nd_async_device_register+0xe/0x50 async_run_entry_fn+0xc3/0x5d0 process_one_work+0xa0a/0x1810 worker_thread+0x87/0xe80 kthread+0x2d7/0x390 ret_from_fork+0x3a/0x50 Add kasan_add_zero_shadow()/kasan_remove_zero_shadow() - post mm_init() interface to map/unmap kasan_zero_page at requested virtual addresses. And use it to add/remove the shadow memory for hotplugged/unplugged device memory. Link: http://lkml.kernel.org/r/20180629164932.740-1-aryabinin@virtuozzo.com Fixes: 41e94a851304 ("add devm_memremap_pages") Signed-off-by: Andrey Ryabinin Reported-by: Dave Chinner Reviewed-by: Dan Williams Tested-by: Dan Williams Cc: Dmitry Vyukov Cc: Alexander Potapenko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/memremap.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'kernel/memremap.c') diff --git a/kernel/memremap.c b/kernel/memremap.c index 38283363da06..1f87ea6b6545 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -5,6 +5,7 @@ #include #include #include +#include #include #include #include @@ -137,6 +138,7 @@ static void devm_memremap_pages_release(void *data) mem_hotplug_begin(); arch_remove_memory(align_start, align_size, pgmap->altmap_valid ? &pgmap->altmap : NULL); + kasan_remove_zero_shadow(__va(align_start), align_size); mem_hotplug_done(); untrack_pfn(NULL, PHYS_PFN(align_start), align_size); @@ -239,6 +241,12 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) goto err_pfn_remap; mem_hotplug_begin(); + error = kasan_add_zero_shadow(__va(align_start), align_size); + if (error) { + mem_hotplug_done(); + goto err_kasan; + } + error = arch_add_memory(nid, align_start, align_size, altmap, false); if (!error) move_pfn_range_to_zone(&NODE_DATA(nid)->node_zones[ZONE_DEVICE], @@ -267,6 +275,8 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) return __va(res->start); err_add_memory: + kasan_remove_zero_shadow(__va(align_start), align_size); + err_kasan: untrack_pfn(NULL, PHYS_PFN(align_start), align_size); err_pfn_remap: err_radix: -- cgit v1.2.3-55-g7522