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authorAndrey Ryabinin <aryabinin@virtuozzo.com>2018-08-17 15:47:04 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-17 16:20:30 -0700
commit0207df4fa1a869281ddbf72db6203dbf036b3e1a (patch)
treeff843a903d9149fd06632658d4984dc724e5e7fa /kernel
parent50f8b92f21d23789bd4ada593e8ddc56cc4f79fe (diff)
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 <aryabinin@virtuozzo.com> Reported-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Tested-by: Dan Williams <dan.j.williams@intel.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Alexander Potapenko <glider@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/memremap.c10
1 files changed, 10 insertions, 0 deletions
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 <linux/types.h>
#include <linux/pfn_t.h>
#include <linux/io.h>
+#include <linux/kasan.h>
#include <linux/mm.h>
#include <linux/memory_hotplug.h>
#include <linux/swap.h>
@@ -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: