Eric Lee / smarc-ti-linux-kernel

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Commit d71f290b4e98a39f49f2595a13be3b4d5ce8e1f1

Authored by James Hogan
1 parent 2425ce8402
Exists in ti-lsk-linux-4.1.y and in 12 other branches dlt-processor-sdk-linux-03.00.00.04, processor-sdk-linux-02.00.01, smarc-ti-linux-3.15.y, smarc-ti-lsk-linux-4.1.y, smarct3x-processor-sdk-04.01.00.06, smarct3x-processor-sdk-linux-02.00.01, smarct3x-processor-sdk-linux-03.00.00.04, smarct4x-800-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-04.01.00.06, smarct4x-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-linux-03.00.00.04, ti-linux-3.15.y

metag: Reduce maximum stack size to 256MB 

Specify the maximum stack size for arches where the stack grows upward
(parisc and metag) in asm/processor.h rather than hard coding in
fs/exec.c so that metag can specify a smaller value of 256MB rather than
1GB.

This fixes a BUG on metag if the RLIMIT_STACK hard limit is increased
beyond a safe value by root. E.g. when starting a process after running
"ulimit -H -s unlimited" it will then attempt to use a stack size of the
maximum 1GB which is far too big for metag's limited user virtual
address space (stack_top is usually 0x3ffff000):

BUG: failure at fs/exec.c:589/shift_arg_pages()!

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: linux-parisc@vger.kernel.org
Cc: linux-metag@vger.kernel.org
Cc: John David Anglin <dave.anglin@bell.net>
Cc: stable@vger.kernel.org # only needed for >= v3.9 (arch/metag)

Showing 3 changed files with 7 additions and 3 deletions Side-by-side Diff

arch/metag/include/asm/processor.h
Diff comments   View file @ d71f290
... ... @@ -22,6 +22,8 @@
22 22 /* Add an extra page of padding at the top of the stack for the guard page. */
23 23 #define STACK_TOP (TASK_SIZE - PAGE_SIZE)
24 24 #define STACK_TOP_MAX STACK_TOP
  25 +/* Maximum virtual space for stack */
  26 +#define STACK_SIZE_MAX (1 << 28) /* 256 MB */
25 27  
26 28 /* This decides where the kernel will search for a free chunk of vm
27 29 * space during mmap's.
arch/parisc/include/asm/processor.h
Diff comments   View file @ d71f290
... ... @@ -55,6 +55,8 @@
55 55 #define STACK_TOP TASK_SIZE
56 56 #define STACK_TOP_MAX DEFAULT_TASK_SIZE
57 57  
  58 +#define STACK_SIZE_MAX (1 << 30) /* 1 GB */
  59 +
58 60 #endif
59 61  
60 62 #ifndef __ASSEMBLY__
... ... @@ -657,10 +657,10 @@
657 657 unsigned long rlim_stack;
658 658  
659 659 #ifdef CONFIG_STACK_GROWSUP
660   - /* Limit stack size to 1GB */
  660 + /* Limit stack size */
661 661 stack_base = rlimit_max(RLIMIT_STACK);
662   - if (stack_base > (1 << 30))
663   - stack_base = 1 << 30;
  662 + if (stack_base > STACK_SIZE_MAX)
  663 + stack_base = STACK_SIZE_MAX;
664 664  
665 665 /* Make sure we didn't let the argument array grow too large. */
666 666 if (vma->vm_end - vma->vm_start > stack_base)