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authorJames Hogan <james.hogan@imgtec.com>2014-05-13 23:58:24 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-06-07 13:25:38 -0700
commit56ecdc3d9e5b91f411e6f3ba63229d332b54af8e (patch)
treee0577e16c1b7479de2b133df1994812257049fe2
parent44563045712ee4f385b5f3814d69fc73b5f22288 (diff)
downloadlinux-56ecdc3d9e5b91f411e6f3ba63229d332b54af8e.tar.gz
metag: Reduce maximum stack size to 256MB
commit d71f290b4e98a39f49f2595a13be3b4d5ce8e1f1 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/metag/include/asm/processor.h2
-rw-r--r--arch/parisc/include/asm/processor.h2
-rw-r--r--fs/exec.c6
3 files changed, 7 insertions, 3 deletions
diff --git a/arch/metag/include/asm/processor.h b/arch/metag/include/asm/processor.h
index 9b029a7911c..579e3d93a5c 100644
--- a/arch/metag/include/asm/processor.h
+++ b/arch/metag/include/asm/processor.h
@@ -22,6 +22,8 @@
/* Add an extra page of padding at the top of the stack for the guard page. */
#define STACK_TOP (TASK_SIZE - PAGE_SIZE)
#define STACK_TOP_MAX STACK_TOP
+/* Maximum virtual space for stack */
+#define STACK_SIZE_MAX (1 << 28) /* 256 MB */
/* This decides where the kernel will search for a free chunk of vm
* space during mmap's.
diff --git a/arch/parisc/include/asm/processor.h b/arch/parisc/include/asm/processor.h
index cc2290a3cac..c6ee86542fe 100644
--- a/arch/parisc/include/asm/processor.h
+++ b/arch/parisc/include/asm/processor.h
@@ -53,6 +53,8 @@
#define STACK_TOP TASK_SIZE
#define STACK_TOP_MAX DEFAULT_TASK_SIZE
+#define STACK_SIZE_MAX (1 << 30) /* 1 GB */
+
#endif
#ifndef __ASSEMBLY__
diff --git a/fs/exec.c b/fs/exec.c
index bb60cda5ee3..dd6aa61c854 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -654,10 +654,10 @@ int setup_arg_pages(struct linux_binprm *bprm,
unsigned long rlim_stack;
#ifdef CONFIG_STACK_GROWSUP
- /* Limit stack size to 1GB */
+ /* Limit stack size */
stack_base = rlimit_max(RLIMIT_STACK);
- if (stack_base > (1 << 30))
- stack_base = 1 << 30;
+ if (stack_base > STACK_SIZE_MAX)
+ stack_base = STACK_SIZE_MAX;
/* Make sure we didn't let the argument array grow too large. */
if (vma->vm_end - vma->vm_start > stack_base)