original_kernel/arch/arc/mm
Eugeniy Paltsev a8c715b4dd ARC: mm: SIGSEGV userspace trying to access kernel virtual memory
As of today if userspace process tries to access a kernel virtual addres
(0x7000_0000 to 0x7ffff_ffff) such that a legit kernel mapping already
exists, that process hangs instead of being killed with SIGSEGV

Fix that by ensuring that do_page_fault() handles kenrel vaddr only if
in kernel mode.

And given this, we can also simplify the code a bit. Now a vmalloc fault
implies kernel mode so its failure (for some reason) can reuse the
@no_context label and we can remove @bad_area_nosemaphore.

Reproduce user test for original problem:

------------------------>8-----------------
 #include <stdlib.h>
 #include <stdint.h>

 int main(int argc, char *argv[])
 {
 	volatile uint32_t temp;

 	temp = *(uint32_t *)(0x70000000);
 }
------------------------>8-----------------

Cc: <stable@vger.kernel.org>
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2019-05-20 10:09:10 -07:00
..
Makefile
cache.c
dma.c
extable.c
fault.c ARC: mm: SIGSEGV userspace trying to access kernel virtual memory 2019-05-20 10:09:10 -07:00
highmem.c
init.c
ioremap.c
mmap.c
tlb.c ARC: fix build warnings 2019-05-20 10:09:10 -07:00
tlbex.S