From: Alex Sverdlin <alexander.sverdlin@xxxxxxxxx> [ Upstream commit 823f606ab6b4759a1faf0388abcf4fb0776710d2 ] In case CONFIG_KASAN_VMALLOC=y kasan_populate_vmalloc() allocates the shadow pages dynamically. But even worse is that kasan_release_vmalloc() releases them, which is not compatible with create_mapping() of MODULES_VADDR..MODULES_END range: BUG: Bad page state in process kworker/9:1 pfn:2068b page:e5e06160 refcount:0 mapcount:0 mapping:00000000 index:0x0 flags: 0x1000(reserved) raw: 00001000 e5e06164 e5e06164 00000000 00000000 00000000 ffffffff 00000000 page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set bad because of flags: 0x1000(reserved) Modules linked in: ip_tables CPU: 9 PID: 154 Comm: kworker/9:1 Not tainted 5.4.188-... #1 Hardware name: LSI Axxia AXM55XX Workqueue: events do_free_init unwind_backtrace show_stack dump_stack bad_page free_pcp_prepare free_unref_page kasan_depopulate_vmalloc_pte __apply_to_page_range apply_to_existing_page_range kasan_release_vmalloc __purge_vmap_area_lazy _vm_unmap_aliases.part.0 __vunmap do_free_init process_one_work worker_thread kthread Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx> Signed-off-by: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx> Signed-off-by: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- arch/arm/mm/kasan_init.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/arm/mm/kasan_init.c b/arch/arm/mm/kasan_init.c index 4b1619584b23..948ada4a2938 100644 --- a/arch/arm/mm/kasan_init.c +++ b/arch/arm/mm/kasan_init.c @@ -264,12 +264,17 @@ void __init kasan_init(void) /* * 1. The module global variables are in MODULES_VADDR ~ MODULES_END, - * so we need to map this area. + * so we need to map this area if CONFIG_KASAN_VMALLOC=n. With + * VMALLOC support KASAN will manage this region dynamically, + * refer to kasan_populate_vmalloc() and ARM's implementation of + * module_alloc(). * 2. PKMAP_BASE ~ PKMAP_BASE+PMD_SIZE's shadow and MODULES_VADDR * ~ MODULES_END's shadow is in the same PMD_SIZE, so we can't * use kasan_populate_zero_shadow. */ - create_mapping((void *)MODULES_VADDR, (void *)(PKMAP_BASE + PMD_SIZE)); + if (!IS_ENABLED(CONFIG_KASAN_VMALLOC) && IS_ENABLED(CONFIG_MODULES)) + create_mapping((void *)MODULES_VADDR, (void *)(MODULES_END)); + create_mapping((void *)PKMAP_BASE, (void *)(PKMAP_BASE + PMD_SIZE)); /* * KAsan may reuse the contents of kasan_early_shadow_pte directly, so -- 2.35.1
