mirror of
https://github.com/team-infusion-developers/android_kernel_samsung_msm8976.git
synced 2024-09-21 03:43:03 +00:00
ARC: Incorrect mm reference used in vmalloc fault handler
commit 9c41f4eeb9d51f3ece20428d35a3ea32cf3b5622 upstream. 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 20bafb3d23d108bc "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: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
27b840ea21
commit
40a894023d
|
@ -16,7 +16,7 @@
|
||||||
#include <linux/kdebug.h>
|
#include <linux/kdebug.h>
|
||||||
#include <asm/pgalloc.h>
|
#include <asm/pgalloc.h>
|
||||||
|
|
||||||
static int handle_vmalloc_fault(struct mm_struct *mm, unsigned long address)
|
static int handle_vmalloc_fault(unsigned long address)
|
||||||
{
|
{
|
||||||
/*
|
/*
|
||||||
* Synchronize this task's top level page-table
|
* Synchronize this task's top level page-table
|
||||||
|
@ -26,7 +26,7 @@ static int handle_vmalloc_fault(struct mm_struct *mm, unsigned long address)
|
||||||
pud_t *pud, *pud_k;
|
pud_t *pud, *pud_k;
|
||||||
pmd_t *pmd, *pmd_k;
|
pmd_t *pmd, *pmd_k;
|
||||||
|
|
||||||
pgd = pgd_offset_fast(mm, address);
|
pgd = pgd_offset_fast(current->active_mm, address);
|
||||||
pgd_k = pgd_offset_k(address);
|
pgd_k = pgd_offset_k(address);
|
||||||
|
|
||||||
if (!pgd_present(*pgd_k))
|
if (!pgd_present(*pgd_k))
|
||||||
|
@ -72,7 +72,7 @@ void do_page_fault(struct pt_regs *regs, int write, unsigned long address,
|
||||||
* nothing more.
|
* nothing more.
|
||||||
*/
|
*/
|
||||||
if (address >= VMALLOC_START && address <= VMALLOC_END) {
|
if (address >= VMALLOC_START && address <= VMALLOC_END) {
|
||||||
ret = handle_vmalloc_fault(mm, address);
|
ret = handle_vmalloc_fault(address);
|
||||||
if (unlikely(ret))
|
if (unlikely(ret))
|
||||||
goto bad_area_nosemaphore;
|
goto bad_area_nosemaphore;
|
||||||
else
|
else
|
||||||
|
|
Loading…
Reference in a new issue