Commit 3f1e2c7a authored Sep 15, 2022 by Alexander Potapenko Committed by Andrew Morton Oct 03, 2022

x86: kmsan: sync metadata pages on page fault

KMSAN assumes shadow and origin pages for every allocated page are
accessible.  For pages between [VMALLOC_START, VMALLOC_END] those metadata
pages start at KMSAN_VMALLOC_SHADOW_START and KMSAN_VMALLOC_ORIGIN_START,
therefore we must sync a bigger memory region.

Link: https://lkml.kernel.org/r/20220915150417.722975-37-glider@google.com


Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

parent ff901d80

arch/x86/mm/fault.c

+22 −1

Original line number	Diff line number	Diff line
		@@ -260,7 +260,7 @@ static noinline int vmalloc_fault(unsigned long address)
		}
		NOKPROBE_SYMBOL(vmalloc_fault);

		void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
		static void __arch_sync_kernel_mappings(unsigned long start, unsigned long end)
		{
		unsigned long addr;

		@@ -284,6 +284,27 @@ void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
		}
		}

		void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
		{
		__arch_sync_kernel_mappings(start, end);
		#ifdef CONFIG_KMSAN
		/*
		* KMSAN maintains two additional metadata page mappings for the
		* [VMALLOC_START, VMALLOC_END) range. These mappings start at
		* KMSAN_VMALLOC_SHADOW_START and KMSAN_VMALLOC_ORIGIN_START and
		* have to be synced together with the vmalloc memory mapping.
		*/
		if (start >= VMALLOC_START && end < VMALLOC_END) {
		__arch_sync_kernel_mappings(
		start - VMALLOC_START + KMSAN_VMALLOC_SHADOW_START,
		end - VMALLOC_START + KMSAN_VMALLOC_SHADOW_START);
		__arch_sync_kernel_mappings(
		start - VMALLOC_START + KMSAN_VMALLOC_ORIGIN_START,
		end - VMALLOC_START + KMSAN_VMALLOC_ORIGIN_START);
		}
		#endif
		}

		static bool low_pfn(unsigned long pfn)
		{
		return pfn < max_low_pfn;