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linux_dsm_epyc7002/arch/arc
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Vineet Gupta 9c41f4eeb9 ARC: Incorrect mm reference used in vmalloc fault handler 
A vmalloc fault needs to sync up PGD/PTE entry from init_mm to current
task's "active_mm".  ARC vmalloc fault handler however was using mm.

A vmalloc fault for non user task context (actually pre-userland, from
init thread's open for /dev/console) caused the handler to deref NULL mm
(for mm->pgd)

The reasons it worked so far is amazing:

1. By default (!SMP), vmalloc fault handler uses a cached value of PGD.
   In SMP that MMU register is repurposed hence need for mm pointer deref.

2. In pre-3.12 SMP kernel, the problem triggering vmalloc didn't exist in
   pre-userland code path - it was introduced with commit 20bafb3d23
   "n_tty: Move buffers into n_tty_data"

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: Noam Camus <noamc@ezchip.com>
Cc: stable@vger.kernel.org    #3.10 and 3.11
Cc: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-02 10:27:04 -07:00
..
boot ARC: Add some .gitignore entries 2013-08-26 09:40:24 +05:30
configs Couple of Platform updates (Device Tree files primarily) given that the 2013-07-10 10:11:26 -07:00
include ARC: Workaround spinlock livelock in SMP SystemC simulation 2013-09-27 16:28:48 +05:30
kernel ARC: Ignore ptrace SETREGSET request for synthetic register "stop_pc" 2013-10-12 12:00:36 +05:30
lib ARC: [lib] strchr breakage in Big-endian configuration 2013-08-24 11:24:53 -07:00
mm ARC: Incorrect mm reference used in vmalloc fault handler 2013-11-02 10:27:04 -07:00
oprofile ARC: OProfile support 2013-02-15 23:16:00 +05:30
plat-arcfpga Couple of Platform updates (Device Tree files primarily) given that the 2013-07-10 10:11:26 -07:00
plat-tb10x ARC: [TB10x] Updates for irqchip driver 2013-06-28 15:07:42 +05:30
Kbuild ARC: Build system: Makefiles, Kconfig, Linker script 2013-02-11 20:00:25 +05:30
Kconfig Remove GENERIC_HARDIRQ config option 2013-09-13 15:09:52 +02:00
Kconfig.debug consolidate per-arch stack overflow debugging options 2013-07-04 11:25:39 -07:00
Makefile ARC: Adjustments for gcc 4.8 2013-06-27 14:35:32 +05:30