linux/arch
James Hogan a816b306c6 MIPS: Don't unwind to user mode with EVA
When unwinding through IRQs and exceptions, the unwinding only continues
if the PC is a kernel text address, however since EVA it is possible for
user and kernel address ranges to overlap, potentially allowing
unwinding to continue to user mode if the user PC happens to be in the
kernel text address range.

Adjust the check to also ensure that the register state from before the
exception is actually running in kernel mode, i.e. !user_mode(regs).

I don't believe any harm can come of this problem, since the PC is only
output, the stack pointer is checked to ensure it resides within the
task's stack page before it is dereferenced in search of the return
address, and the return address register is similarly only output (if
the PC is in a leaf function or the beginning of a non-leaf function).

However unwind_stack() is only meant for unwinding kernel code, so to be
correct the unwind should stop there.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 3.15+
Patchwork: https://patchwork.linux-mips.org/patch/11700/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-09 12:00:02 +02:00
..
alpha alpha/extable: use generic search and sort routines 2016-03-22 15:36:02 -07:00
arc ARC: support HIGHMEM even without PAE40 2016-05-05 16:35:46 +05:30
arm Merge branch 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm 2016-05-07 08:27:35 -07:00
arm64 Here are a couple last-minute fixes for ARM SoCs. Most of them 2016-05-05 15:31:35 -07:00
avr32 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2016-03-19 10:05:34 -07:00
blackfin arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
c6x arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
cris Merge branch 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-03-20 19:08:56 -07:00
frv asm-generic changes for 4.6 2016-03-24 23:13:48 -07:00
h8300 h8300: switch EARLYCON 2016-03-25 01:45:19 +09:00
hexagon Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2016-03-19 10:05:34 -07:00
ia64 [IA64] Enable preadv2 and pwritev2 syscalls for ia64 2016-03-25 14:37:32 -07:00
m32r Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2016-03-19 10:05:34 -07:00
m68k Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu 2016-04-13 08:58:32 -07:00
metag arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
microblaze arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
mips MIPS: Don't unwind to user mode with EVA 2016-05-09 12:00:02 +02:00
mn10300 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2016-03-19 10:05:34 -07:00
nios2 nios2: memset: use the right constraint modifier for the %4 output operand 2016-04-27 16:35:55 +08:00
openrisc arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
parisc parisc: fix a bug when syscall number of tracee is __NR_Linux_syscalls 2016-05-06 15:09:07 +02:00
powerpc powerpc fixes for 4.6 #4 2016-05-06 11:05:07 -07:00
s390 s390/mm: fix asce_bits handling with dynamic pagetable levels 2016-04-21 09:50:09 +02:00
score Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2016-03-19 10:05:34 -07:00
sh sh: fix function signature of cpu_coregroup_mask to match pointer type 2016-03-30 00:47:49 +00:00
sparc sparc64: Fix bootup regressions on some Kconfig combinations. 2016-04-27 17:27:37 -04:00
tile Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile 2016-03-28 15:04:55 -05:00
um fs/coredump: prevent fsuid=0 dumps into user-controlled directories 2016-03-22 15:36:02 -07:00
unicore32 Merge branch 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-03-20 19:08:56 -07:00
x86 Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-05-06 12:59:27 -07:00
xtensa Xtensa improvements for 4.6: 2016-03-20 12:22:07 -07:00
.gitignore
Kconfig objtool: Add CONFIG_STACK_VALIDATION option 2016-02-29 08:35:13 +01:00