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@@ -0,0 +1,940 @@
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+From f2ca8eceb0ddcdb6b113b3edd3dfd36c171854f6 Mon Sep 17 00:00:00 2001
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+From: Hugh Dickins <[email protected]>
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+Date: Mon, 19 Jun 2017 04:03:24 -0700
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+Subject: [PATCH 3/4] mm: larger stack guard gap, between vmas
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+MIME-Version: 1.0
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+Content-Type: text/plain; charset=UTF-8
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+Content-Transfer-Encoding: 8bit
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+
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+commit 1be7107fbe18eed3e319a6c3e83c78254b693acb upstream.
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+
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+Stack guard page is a useful feature to reduce a risk of stack smashing
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+into a different mapping. We have been using a single page gap which
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+is sufficient to prevent having stack adjacent to a different mapping.
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+But this seems to be insufficient in the light of the stack usage in
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+userspace. E.g. glibc uses as large as 64kB alloca() in many commonly
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+used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX]
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+which is 256kB or stack strings with MAX_ARG_STRLEN.
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+
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+This will become especially dangerous for suid binaries and the default
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+no limit for the stack size limit because those applications can be
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+tricked to consume a large portion of the stack and a single glibc call
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+could jump over the guard page. These attacks are not theoretical,
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+unfortunatelly.
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+
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+Make those attacks less probable by increasing the stack guard gap
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+to 1MB (on systems with 4k pages; but make it depend on the page size
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+because systems with larger base pages might cap stack allocations in
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+the PAGE_SIZE units) which should cover larger alloca() and VLA stack
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+allocations. It is obviously not a full fix because the problem is
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+somehow inherent, but it should reduce attack space a lot.
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+
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+One could argue that the gap size should be configurable from userspace,
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+but that can be done later when somebody finds that the new 1MB is wrong
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+for some special case applications. For now, add a kernel command line
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+option (stack_guard_gap) to specify the stack gap size (in page units).
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+
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+Implementation wise, first delete all the old code for stack guard page:
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+because although we could get away with accounting one extra page in a
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+stack vma, accounting a larger gap can break userspace - case in point,
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+a program run with "ulimit -S -v 20000" failed when the 1MB gap was
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+counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK
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+and strict non-overcommit mode.
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+
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+Instead of keeping gap inside the stack vma, maintain the stack guard
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+gap as a gap between vmas: using vm_start_gap() in place of vm_start
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+(or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few
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+places which need to respect the gap - mainly arch_get_unmapped_area(),
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+and and the vma tree's subtree_gap support for that.
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+
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+Original-patch-by: Oleg Nesterov <[email protected]>
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+Original-patch-by: Michal Hocko <[email protected]>
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+Signed-off-by: Hugh Dickins <[email protected]>
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+Acked-by: Michal Hocko <[email protected]>
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+Tested-by: Helge Deller <[email protected]> # parisc
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+Signed-off-by: Linus Torvalds <[email protected]>
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+[wt: backport to 4.11: adjust context]
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+Signed-off-by: Willy Tarreau <[email protected]>
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+Signed-off-by: Greg Kroah-Hartman <[email protected]>
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+[fg: backport to 4.10: adjust context]
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+
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+Signed-off-by: Fabian Grünbichler <[email protected]>
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+---
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+ Documentation/admin-guide/kernel-parameters.txt | 7 ++
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+ include/linux/mm.h | 53 ++++-----
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+ arch/arc/mm/mmap.c | 2 +-
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+ arch/arm/mm/mmap.c | 4 +-
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+ arch/frv/mm/elf-fdpic.c | 2 +-
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+ arch/mips/mm/mmap.c | 2 +-
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+ arch/parisc/kernel/sys_parisc.c | 15 ++-
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+ arch/powerpc/mm/hugetlbpage-radix.c | 2 +-
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+ arch/powerpc/mm/mmap.c | 4 +-
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+ arch/powerpc/mm/slice.c | 2 +-
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+ arch/s390/mm/mmap.c | 4 +-
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+ arch/sh/mm/mmap.c | 4 +-
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+ arch/sparc/kernel/sys_sparc_64.c | 4 +-
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+ arch/sparc/mm/hugetlbpage.c | 2 +-
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+ arch/tile/mm/hugetlbpage.c | 2 +-
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+ arch/x86/kernel/sys_x86_64.c | 4 +-
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+ arch/x86/mm/hugetlbpage.c | 2 +-
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+ arch/xtensa/kernel/syscall.c | 2 +-
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+ fs/hugetlbfs/inode.c | 2 +-
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+ fs/proc/task_mmu.c | 4 -
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+ mm/gup.c | 5 -
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+ mm/memory.c | 38 ------
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+ mm/mmap.c | 149 ++++++++++++++----------
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+ 23 files changed, 152 insertions(+), 163 deletions(-)
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+
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+diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
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+index d034a76bcae6..9eb4da6e980a 100644
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+--- a/Documentation/admin-guide/kernel-parameters.txt
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++++ b/Documentation/admin-guide/kernel-parameters.txt
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+@@ -3744,6 +3744,13 @@
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+ spia_pedr=
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+ spia_peddr=
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+
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++ stack_guard_gap= [MM]
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++ override the default stack gap protection. The value
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++ is in page units and it defines how many pages prior
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++ to (for stacks growing down) resp. after (for stacks
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++ growing up) the main stack are reserved for no other
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++ mapping. Default value is 256 pages.
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++
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+ stacktrace [FTRACE]
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+ Enabled the stack tracer on boot up.
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+
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+diff --git a/include/linux/mm.h b/include/linux/mm.h
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+index 3978a350e9e4..705bf34d0805 100644
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+--- a/include/linux/mm.h
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++++ b/include/linux/mm.h
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+@@ -1366,39 +1366,11 @@ int clear_page_dirty_for_io(struct page *page);
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+
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+ int get_cmdline(struct task_struct *task, char *buffer, int buflen);
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+
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+-/* Is the vma a continuation of the stack vma above it? */
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+-static inline int vma_growsdown(struct vm_area_struct *vma, unsigned long addr)
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+-{
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+- return vma && (vma->vm_end == addr) && (vma->vm_flags & VM_GROWSDOWN);
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+-}
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+-
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+ static inline bool vma_is_anonymous(struct vm_area_struct *vma)
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+ {
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+ return !vma->vm_ops;
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+ }
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+
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+-static inline int stack_guard_page_start(struct vm_area_struct *vma,
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+- unsigned long addr)
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+-{
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+- return (vma->vm_flags & VM_GROWSDOWN) &&
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+- (vma->vm_start == addr) &&
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+- !vma_growsdown(vma->vm_prev, addr);
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+-}
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+-
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+-/* Is the vma a continuation of the stack vma below it? */
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+-static inline int vma_growsup(struct vm_area_struct *vma, unsigned long addr)
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+-{
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+- return vma && (vma->vm_start == addr) && (vma->vm_flags & VM_GROWSUP);
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+-}
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+-
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+-static inline int stack_guard_page_end(struct vm_area_struct *vma,
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+- unsigned long addr)
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+-{
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+- return (vma->vm_flags & VM_GROWSUP) &&
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+- (vma->vm_end == addr) &&
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+- !vma_growsup(vma->vm_next, addr);
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+-}
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+-
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+ int vma_is_stack_for_current(struct vm_area_struct *vma);
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+
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+ extern unsigned long move_page_tables(struct vm_area_struct *vma,
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+@@ -2139,6 +2111,7 @@ void page_cache_async_readahead(struct address_space *mapping,
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+ pgoff_t offset,
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+ unsigned long size);
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+
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++extern unsigned long stack_guard_gap;
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+ /* Generic expand stack which grows the stack according to GROWS{UP,DOWN} */
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+ extern int expand_stack(struct vm_area_struct *vma, unsigned long address);
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+
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+@@ -2167,6 +2140,30 @@ static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * m
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+ return vma;
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+ }
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+
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++static inline unsigned long vm_start_gap(struct vm_area_struct *vma)
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++{
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++ unsigned long vm_start = vma->vm_start;
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++
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++ if (vma->vm_flags & VM_GROWSDOWN) {
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++ vm_start -= stack_guard_gap;
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++ if (vm_start > vma->vm_start)
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++ vm_start = 0;
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++ }
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++ return vm_start;
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++}
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++
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++static inline unsigned long vm_end_gap(struct vm_area_struct *vma)
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++{
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++ unsigned long vm_end = vma->vm_end;
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++
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++ if (vma->vm_flags & VM_GROWSUP) {
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++ vm_end += stack_guard_gap;
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++ if (vm_end < vma->vm_end)
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++ vm_end = -PAGE_SIZE;
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++ }
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++ return vm_end;
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++}
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++
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+ static inline unsigned long vma_pages(struct vm_area_struct *vma)
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+ {
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+ return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
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+diff --git a/arch/arc/mm/mmap.c b/arch/arc/mm/mmap.c
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+index 2e06d56e987b..cf4ae6958240 100644
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+--- a/arch/arc/mm/mmap.c
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++++ b/arch/arc/mm/mmap.c
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+@@ -64,7 +64,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
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+
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+ vma = find_vma(mm, addr);
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+ if (TASK_SIZE - len >= addr &&
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+- (!vma || addr + len <= vma->vm_start))
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++ (!vma || addr + len <= vm_start_gap(vma)))
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+ return addr;
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+ }
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+
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+diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
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+index 66353caa35b9..641334ebf46d 100644
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+--- a/arch/arm/mm/mmap.c
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++++ b/arch/arm/mm/mmap.c
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+@@ -89,7 +89,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
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+
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+ vma = find_vma(mm, addr);
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+ if (TASK_SIZE - len >= addr &&
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+- (!vma || addr + len <= vma->vm_start))
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++ (!vma || addr + len <= vm_start_gap(vma)))
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+ return addr;
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+ }
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+
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+@@ -140,7 +140,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
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+ addr = PAGE_ALIGN(addr);
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+ vma = find_vma(mm, addr);
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+ if (TASK_SIZE - len >= addr &&
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+- (!vma || addr + len <= vma->vm_start))
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++ (!vma || addr + len <= vm_start_gap(vma)))
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+ return addr;
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+ }
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+
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+diff --git a/arch/frv/mm/elf-fdpic.c b/arch/frv/mm/elf-fdpic.c
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+index 836f14707a62..efa59f1f8022 100644
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+--- a/arch/frv/mm/elf-fdpic.c
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++++ b/arch/frv/mm/elf-fdpic.c
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+@@ -74,7 +74,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsi
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+ addr = PAGE_ALIGN(addr);
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+ vma = find_vma(current->mm, addr);
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+ if (TASK_SIZE - len >= addr &&
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+- (!vma || addr + len <= vma->vm_start))
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++ (!vma || addr + len <= vm_start_gap(vma)))
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+ goto success;
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+ }
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+
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+diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c
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+index d08ea3ff0f53..a44052c05f93 100644
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+--- a/arch/mips/mm/mmap.c
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++++ b/arch/mips/mm/mmap.c
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+@@ -92,7 +92,7 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp,
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+
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+ vma = find_vma(mm, addr);
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+ if (TASK_SIZE - len >= addr &&
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+- (!vma || addr + len <= vma->vm_start))
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++ (!vma || addr + len <= vm_start_gap(vma)))
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+ return addr;
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+ }
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+
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+diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c
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+index bf3294171230..5fb3f0ef2906 100644
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+--- a/arch/parisc/kernel/sys_parisc.c
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++++ b/arch/parisc/kernel/sys_parisc.c
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+@@ -88,7 +88,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
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+ unsigned long len, unsigned long pgoff, unsigned long flags)
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+ {
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+ struct mm_struct *mm = current->mm;
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+- struct vm_area_struct *vma;
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++ struct vm_area_struct *vma, *prev;
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+ unsigned long task_size = TASK_SIZE;
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+ int do_color_align, last_mmap;
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+ struct vm_unmapped_area_info info;
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+@@ -115,9 +115,10 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
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+ else
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+ addr = PAGE_ALIGN(addr);
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+
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+- vma = find_vma(mm, addr);
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++ vma = find_vma_prev(mm, addr, &prev);
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+ if (task_size - len >= addr &&
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+- (!vma || addr + len <= vma->vm_start))
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++ (!vma || addr + len <= vm_start_gap(vma)) &&
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++ (!prev || addr >= vm_end_gap(prev)))
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+ goto found_addr;
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+ }
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+
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+@@ -141,7 +142,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
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+ const unsigned long len, const unsigned long pgoff,
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+ const unsigned long flags)
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+ {
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+- struct vm_area_struct *vma;
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++ struct vm_area_struct *vma, *prev;
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+ struct mm_struct *mm = current->mm;
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+ unsigned long addr = addr0;
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+ int do_color_align, last_mmap;
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+@@ -175,9 +176,11 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
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+ addr = COLOR_ALIGN(addr, last_mmap, pgoff);
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+ else
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+ addr = PAGE_ALIGN(addr);
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+- vma = find_vma(mm, addr);
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++
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++ vma = find_vma_prev(mm, addr, &prev);
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+ if (TASK_SIZE - len >= addr &&
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+- (!vma || addr + len <= vma->vm_start))
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++ (!vma || addr + len <= vm_start_gap(vma)) &&
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++ (!prev || addr >= vm_end_gap(prev)))
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+ goto found_addr;
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+ }
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+
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+diff --git a/arch/powerpc/mm/hugetlbpage-radix.c b/arch/powerpc/mm/hugetlbpage-radix.c
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+index 35254a678456..a2b2d97f7eda 100644
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+--- a/arch/powerpc/mm/hugetlbpage-radix.c
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++++ b/arch/powerpc/mm/hugetlbpage-radix.c
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+@@ -65,7 +65,7 @@ radix__hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
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+ addr = ALIGN(addr, huge_page_size(h));
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+ vma = find_vma(mm, addr);
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+ if (TASK_SIZE - len >= addr &&
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+- (!vma || addr + len <= vma->vm_start))
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++ (!vma || addr + len <= vm_start_gap(vma)))
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+ return addr;
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+ }
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+ /*
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+diff --git a/arch/powerpc/mm/mmap.c b/arch/powerpc/mm/mmap.c
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+index 2f1e44362198..5bc2845cddf4 100644
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+--- a/arch/powerpc/mm/mmap.c
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++++ b/arch/powerpc/mm/mmap.c
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+@@ -106,7 +106,7 @@ radix__arch_get_unmapped_area(struct file *filp, unsigned long addr,
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+ addr = PAGE_ALIGN(addr);
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+ vma = find_vma(mm, addr);
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+ if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
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+- (!vma || addr + len <= vma->vm_start))
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++ (!vma || addr + len <= vm_start_gap(vma)))
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+ return addr;
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+ }
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+
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+@@ -142,7 +142,7 @@ radix__arch_get_unmapped_area_topdown(struct file *filp,
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+ addr = PAGE_ALIGN(addr);
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+ vma = find_vma(mm, addr);
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+ if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
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+- (!vma || addr + len <= vma->vm_start))
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++ (!vma || addr + len <= vm_start_gap(vma)))
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+ return addr;
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+ }
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+
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+diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
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+index 2b27458902ee..c4d5c9c61e0f 100644
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+--- a/arch/powerpc/mm/slice.c
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++++ b/arch/powerpc/mm/slice.c
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|
|
+@@ -105,7 +105,7 @@ static int slice_area_is_free(struct mm_struct *mm, unsigned long addr,
|
|
|
+ if ((mm->task_size - len) < addr)
|
|
|
+ return 0;
|
|
|
+ vma = find_vma(mm, addr);
|
|
|
+- return (!vma || (addr + len) <= vma->vm_start);
|
|
|
++ return (!vma || (addr + len) <= vm_start_gap(vma));
|
|
|
+ }
|
|
|
+
|
|
|
+ static int slice_low_has_vma(struct mm_struct *mm, unsigned long slice)
|
|
|
+diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
|
|
|
+index eb9df2822da1..812368f274c9 100644
|
|
|
+--- a/arch/s390/mm/mmap.c
|
|
|
++++ b/arch/s390/mm/mmap.c
|
|
|
+@@ -98,7 +98,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
|
|
|
+ addr = PAGE_ALIGN(addr);
|
|
|
+ vma = find_vma(mm, addr);
|
|
|
+ if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
|
|
|
+- (!vma || addr + len <= vma->vm_start))
|
|
|
++ (!vma || addr + len <= vm_start_gap(vma)))
|
|
|
+ return addr;
|
|
|
+ }
|
|
|
+
|
|
|
+@@ -136,7 +136,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
|
|
|
+ addr = PAGE_ALIGN(addr);
|
|
|
+ vma = find_vma(mm, addr);
|
|
|
+ if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
|
|
|
+- (!vma || addr + len <= vma->vm_start))
|
|
|
++ (!vma || addr + len <= vm_start_gap(vma)))
|
|
|
+ return addr;
|
|
|
+ }
|
|
|
+
|
|
|
+diff --git a/arch/sh/mm/mmap.c b/arch/sh/mm/mmap.c
|
|
|
+index 6777177807c2..7df7d5944188 100644
|
|
|
+--- a/arch/sh/mm/mmap.c
|
|
|
++++ b/arch/sh/mm/mmap.c
|
|
|
+@@ -63,7 +63,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
|
|
|
+
|
|
|
+ vma = find_vma(mm, addr);
|
|
|
+ if (TASK_SIZE - len >= addr &&
|
|
|
+- (!vma || addr + len <= vma->vm_start))
|
|
|
++ (!vma || addr + len <= vm_start_gap(vma)))
|
|
|
+ return addr;
|
|
|
+ }
|
|
|
+
|
|
|
+@@ -113,7 +113,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
|
|
|
+
|
|
|
+ vma = find_vma(mm, addr);
|
|
|
+ if (TASK_SIZE - len >= addr &&
|
|
|
+- (!vma || addr + len <= vma->vm_start))
|
|
|
++ (!vma || addr + len <= vm_start_gap(vma)))
|
|
|
+ return addr;
|
|
|
+ }
|
|
|
+
|
|
|
+diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
|
|
|
+index 884c70331345..f39dd87b77c4 100644
|
|
|
+--- a/arch/sparc/kernel/sys_sparc_64.c
|
|
|
++++ b/arch/sparc/kernel/sys_sparc_64.c
|
|
|
+@@ -118,7 +118,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsi
|
|
|
+
|
|
|
+ vma = find_vma(mm, addr);
|
|
|
+ if (task_size - len >= addr &&
|
|
|
+- (!vma || addr + len <= vma->vm_start))
|
|
|
++ (!vma || addr + len <= vm_start_gap(vma)))
|
|
|
+ return addr;
|
|
|
+ }
|
|
|
+
|
|
|
+@@ -181,7 +181,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
|
|
|
+
|
|
|
+ vma = find_vma(mm, addr);
|
|
|
+ if (task_size - len >= addr &&
|
|
|
+- (!vma || addr + len <= vma->vm_start))
|
|
|
++ (!vma || addr + len <= vm_start_gap(vma)))
|
|
|
+ return addr;
|
|
|
+ }
|
|
|
+
|
|
|
+diff --git a/arch/sparc/mm/hugetlbpage.c b/arch/sparc/mm/hugetlbpage.c
|
|
|
+index 988acc8b1b80..58cde8d9be8a 100644
|
|
|
+--- a/arch/sparc/mm/hugetlbpage.c
|
|
|
++++ b/arch/sparc/mm/hugetlbpage.c
|
|
|
+@@ -116,7 +116,7 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
|
|
|
+ addr = ALIGN(addr, HPAGE_SIZE);
|
|
|
+ vma = find_vma(mm, addr);
|
|
|
+ if (task_size - len >= addr &&
|
|
|
+- (!vma || addr + len <= vma->vm_start))
|
|
|
++ (!vma || addr + len <= vm_start_gap(vma)))
|
|
|
+ return addr;
|
|
|
+ }
|
|
|
+ if (mm->get_unmapped_area == arch_get_unmapped_area)
|
|
|
+diff --git a/arch/tile/mm/hugetlbpage.c b/arch/tile/mm/hugetlbpage.c
|
|
|
+index 77ceaa343fce..67508b249ede 100644
|
|
|
+--- a/arch/tile/mm/hugetlbpage.c
|
|
|
++++ b/arch/tile/mm/hugetlbpage.c
|
|
|
+@@ -232,7 +232,7 @@ unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
|
|
|
+ addr = ALIGN(addr, huge_page_size(h));
|
|
|
+ vma = find_vma(mm, addr);
|
|
|
+ if (TASK_SIZE - len >= addr &&
|
|
|
+- (!vma || addr + len <= vma->vm_start))
|
|
|
++ (!vma || addr + len <= vm_start_gap(vma)))
|
|
|
+ return addr;
|
|
|
+ }
|
|
|
+ if (current->mm->get_unmapped_area == arch_get_unmapped_area)
|
|
|
+diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
|
|
|
+index a55ed63b9f91..1119414ab419 100644
|
|
|
+--- a/arch/x86/kernel/sys_x86_64.c
|
|
|
++++ b/arch/x86/kernel/sys_x86_64.c
|
|
|
+@@ -140,7 +140,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
|
|
|
+ addr = PAGE_ALIGN(addr);
|
|
|
+ vma = find_vma(mm, addr);
|
|
|
+ if (end - len >= addr &&
|
|
|
+- (!vma || addr + len <= vma->vm_start))
|
|
|
++ (!vma || addr + len <= vm_start_gap(vma)))
|
|
|
+ return addr;
|
|
|
+ }
|
|
|
+
|
|
|
+@@ -183,7 +183,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
|
|
|
+ addr = PAGE_ALIGN(addr);
|
|
|
+ vma = find_vma(mm, addr);
|
|
|
+ if (TASK_SIZE - len >= addr &&
|
|
|
+- (!vma || addr + len <= vma->vm_start))
|
|
|
++ (!vma || addr + len <= vm_start_gap(vma)))
|
|
|
+ return addr;
|
|
|
+ }
|
|
|
+
|
|
|
+diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c
|
|
|
+index 2ae8584b44c7..fe342e8ed529 100644
|
|
|
+--- a/arch/x86/mm/hugetlbpage.c
|
|
|
++++ b/arch/x86/mm/hugetlbpage.c
|
|
|
+@@ -144,7 +144,7 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
|
|
|
+ addr = ALIGN(addr, huge_page_size(h));
|
|
|
+ vma = find_vma(mm, addr);
|
|
|
+ if (TASK_SIZE - len >= addr &&
|
|
|
+- (!vma || addr + len <= vma->vm_start))
|
|
|
++ (!vma || addr + len <= vm_start_gap(vma)))
|
|
|
+ return addr;
|
|
|
+ }
|
|
|
+ if (mm->get_unmapped_area == arch_get_unmapped_area)
|
|
|
+diff --git a/arch/xtensa/kernel/syscall.c b/arch/xtensa/kernel/syscall.c
|
|
|
+index d3fd100dffc9..dceb0ee37db3 100644
|
|
|
+--- a/arch/xtensa/kernel/syscall.c
|
|
|
++++ b/arch/xtensa/kernel/syscall.c
|
|
|
+@@ -87,7 +87,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
|
|
|
+ /* At this point: (!vmm || addr < vmm->vm_end). */
|
|
|
+ if (TASK_SIZE - len < addr)
|
|
|
+ return -ENOMEM;
|
|
|
+- if (!vmm || addr + len <= vmm->vm_start)
|
|
|
++ if (!vmm || addr + len <= vm_start_gap(vmm))
|
|
|
+ return addr;
|
|
|
+ addr = vmm->vm_end;
|
|
|
+ if (flags & MAP_SHARED)
|
|
|
+diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
|
|
|
+index 54de77e78775..19a787eb8a00 100644
|
|
|
+--- a/fs/hugetlbfs/inode.c
|
|
|
++++ b/fs/hugetlbfs/inode.c
|
|
|
+@@ -191,7 +191,7 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
|
|
|
+ addr = ALIGN(addr, huge_page_size(h));
|
|
|
+ vma = find_vma(mm, addr);
|
|
|
+ if (TASK_SIZE - len >= addr &&
|
|
|
+- (!vma || addr + len <= vma->vm_start))
|
|
|
++ (!vma || addr + len <= vm_start_gap(vma)))
|
|
|
+ return addr;
|
|
|
+ }
|
|
|
+
|
|
|
+diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
|
|
|
+index 52049b595b0f..5e6bab59e219 100644
|
|
|
+--- a/fs/proc/task_mmu.c
|
|
|
++++ b/fs/proc/task_mmu.c
|
|
|
+@@ -302,11 +302,7 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid)
|
|
|
+
|
|
|
+ /* We don't show the stack guard page in /proc/maps */
|
|
|
+ start = vma->vm_start;
|
|
|
+- if (stack_guard_page_start(vma, start))
|
|
|
+- start += PAGE_SIZE;
|
|
|
+ end = vma->vm_end;
|
|
|
+- if (stack_guard_page_end(vma, end))
|
|
|
+- end -= PAGE_SIZE;
|
|
|
+
|
|
|
+ seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
|
|
|
+ seq_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
|
|
|
+diff --git a/mm/gup.c b/mm/gup.c
|
|
|
+index bb5f3d69f87e..bdd74b782b6e 100644
|
|
|
+--- a/mm/gup.c
|
|
|
++++ b/mm/gup.c
|
|
|
+@@ -371,11 +371,6 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma,
|
|
|
+ /* mlock all present pages, but do not fault in new pages */
|
|
|
+ if ((*flags & (FOLL_POPULATE | FOLL_MLOCK)) == FOLL_MLOCK)
|
|
|
+ return -ENOENT;
|
|
|
+- /* For mm_populate(), just skip the stack guard page. */
|
|
|
+- if ((*flags & FOLL_POPULATE) &&
|
|
|
+- (stack_guard_page_start(vma, address) ||
|
|
|
+- stack_guard_page_end(vma, address + PAGE_SIZE)))
|
|
|
+- return -ENOENT;
|
|
|
+ if (*flags & FOLL_WRITE)
|
|
|
+ fault_flags |= FAULT_FLAG_WRITE;
|
|
|
+ if (*flags & FOLL_REMOTE)
|
|
|
+diff --git a/mm/memory.c b/mm/memory.c
|
|
|
+index c89214451507..6d54a9b15520 100644
|
|
|
+--- a/mm/memory.c
|
|
|
++++ b/mm/memory.c
|
|
|
+@@ -2715,40 +2715,6 @@ int do_swap_page(struct vm_fault *vmf)
|
|
|
+ }
|
|
|
+
|
|
|
+ /*
|
|
|
+- * This is like a special single-page "expand_{down|up}wards()",
|
|
|
+- * except we must first make sure that 'address{-|+}PAGE_SIZE'
|
|
|
+- * doesn't hit another vma.
|
|
|
+- */
|
|
|
+-static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address)
|
|
|
+-{
|
|
|
+- address &= PAGE_MASK;
|
|
|
+- if ((vma->vm_flags & VM_GROWSDOWN) && address == vma->vm_start) {
|
|
|
+- struct vm_area_struct *prev = vma->vm_prev;
|
|
|
+-
|
|
|
+- /*
|
|
|
+- * Is there a mapping abutting this one below?
|
|
|
+- *
|
|
|
+- * That's only ok if it's the same stack mapping
|
|
|
+- * that has gotten split..
|
|
|
+- */
|
|
|
+- if (prev && prev->vm_end == address)
|
|
|
+- return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM;
|
|
|
+-
|
|
|
+- return expand_downwards(vma, address - PAGE_SIZE);
|
|
|
+- }
|
|
|
+- if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) {
|
|
|
+- struct vm_area_struct *next = vma->vm_next;
|
|
|
+-
|
|
|
+- /* As VM_GROWSDOWN but s/below/above/ */
|
|
|
+- if (next && next->vm_start == address + PAGE_SIZE)
|
|
|
+- return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM;
|
|
|
+-
|
|
|
+- return expand_upwards(vma, address + PAGE_SIZE);
|
|
|
+- }
|
|
|
+- return 0;
|
|
|
+-}
|
|
|
+-
|
|
|
+-/*
|
|
|
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
|
|
|
+ * but allow concurrent faults), and pte mapped but not yet locked.
|
|
|
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
|
|
|
+@@ -2764,10 +2730,6 @@ static int do_anonymous_page(struct vm_fault *vmf)
|
|
|
+ if (vma->vm_flags & VM_SHARED)
|
|
|
+ return VM_FAULT_SIGBUS;
|
|
|
+
|
|
|
+- /* Check if we need to add a guard page to the stack */
|
|
|
+- if (check_stack_guard_page(vma, vmf->address) < 0)
|
|
|
+- return VM_FAULT_SIGSEGV;
|
|
|
+-
|
|
|
+ /*
|
|
|
+ * Use pte_alloc() instead of pte_alloc_map(). We can't run
|
|
|
+ * pte_offset_map() on pmds where a huge pmd might be created
|
|
|
+diff --git a/mm/mmap.c b/mm/mmap.c
|
|
|
+index 4b3a2aaa18e9..4acc20fc5c81 100644
|
|
|
+--- a/mm/mmap.c
|
|
|
++++ b/mm/mmap.c
|
|
|
+@@ -183,6 +183,7 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
|
|
|
+ unsigned long retval;
|
|
|
+ unsigned long newbrk, oldbrk;
|
|
|
+ struct mm_struct *mm = current->mm;
|
|
|
++ struct vm_area_struct *next;
|
|
|
+ unsigned long min_brk;
|
|
|
+ bool populate;
|
|
|
+
|
|
|
+@@ -228,7 +229,8 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
|
|
|
+ }
|
|
|
+
|
|
|
+ /* Check against existing mmap mappings. */
|
|
|
+- if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
|
|
|
++ next = find_vma(mm, oldbrk);
|
|
|
++ if (next && newbrk + PAGE_SIZE > vm_start_gap(next))
|
|
|
+ goto out;
|
|
|
+
|
|
|
+ /* Ok, looks good - let it rip. */
|
|
|
+@@ -251,10 +253,22 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
|
|
|
+
|
|
|
+ static long vma_compute_subtree_gap(struct vm_area_struct *vma)
|
|
|
+ {
|
|
|
+- unsigned long max, subtree_gap;
|
|
|
+- max = vma->vm_start;
|
|
|
+- if (vma->vm_prev)
|
|
|
+- max -= vma->vm_prev->vm_end;
|
|
|
++ unsigned long max, prev_end, subtree_gap;
|
|
|
++
|
|
|
++ /*
|
|
|
++ * Note: in the rare case of a VM_GROWSDOWN above a VM_GROWSUP, we
|
|
|
++ * allow two stack_guard_gaps between them here, and when choosing
|
|
|
++ * an unmapped area; whereas when expanding we only require one.
|
|
|
++ * That's a little inconsistent, but keeps the code here simpler.
|
|
|
++ */
|
|
|
++ max = vm_start_gap(vma);
|
|
|
++ if (vma->vm_prev) {
|
|
|
++ prev_end = vm_end_gap(vma->vm_prev);
|
|
|
++ if (max > prev_end)
|
|
|
++ max -= prev_end;
|
|
|
++ else
|
|
|
++ max = 0;
|
|
|
++ }
|
|
|
+ if (vma->vm_rb.rb_left) {
|
|
|
+ subtree_gap = rb_entry(vma->vm_rb.rb_left,
|
|
|
+ struct vm_area_struct, vm_rb)->rb_subtree_gap;
|
|
|
+@@ -350,7 +364,7 @@ static void validate_mm(struct mm_struct *mm)
|
|
|
+ anon_vma_unlock_read(anon_vma);
|
|
|
+ }
|
|
|
+
|
|
|
+- highest_address = vma->vm_end;
|
|
|
++ highest_address = vm_end_gap(vma);
|
|
|
+ vma = vma->vm_next;
|
|
|
+ i++;
|
|
|
+ }
|
|
|
+@@ -539,7 +553,7 @@ void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
|
|
|
+ if (vma->vm_next)
|
|
|
+ vma_gap_update(vma->vm_next);
|
|
|
+ else
|
|
|
+- mm->highest_vm_end = vma->vm_end;
|
|
|
++ mm->highest_vm_end = vm_end_gap(vma);
|
|
|
+
|
|
|
+ /*
|
|
|
+ * vma->vm_prev wasn't known when we followed the rbtree to find the
|
|
|
+@@ -854,7 +868,7 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
|
|
|
+ vma_gap_update(vma);
|
|
|
+ if (end_changed) {
|
|
|
+ if (!next)
|
|
|
+- mm->highest_vm_end = end;
|
|
|
++ mm->highest_vm_end = vm_end_gap(vma);
|
|
|
+ else if (!adjust_next)
|
|
|
+ vma_gap_update(next);
|
|
|
+ }
|
|
|
+@@ -939,7 +953,7 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
|
|
|
+ * mm->highest_vm_end doesn't need any update
|
|
|
+ * in remove_next == 1 case.
|
|
|
+ */
|
|
|
+- VM_WARN_ON(mm->highest_vm_end != end);
|
|
|
++ VM_WARN_ON(mm->highest_vm_end != vm_end_gap(vma));
|
|
|
+ }
|
|
|
+ }
|
|
|
+ if (insert && file)
|
|
|
+@@ -1783,7 +1797,7 @@ unsigned long unmapped_area(struct vm_unmapped_area_info *info)
|
|
|
+
|
|
|
+ while (true) {
|
|
|
+ /* Visit left subtree if it looks promising */
|
|
|
+- gap_end = vma->vm_start;
|
|
|
++ gap_end = vm_start_gap(vma);
|
|
|
+ if (gap_end >= low_limit && vma->vm_rb.rb_left) {
|
|
|
+ struct vm_area_struct *left =
|
|
|
+ rb_entry(vma->vm_rb.rb_left,
|
|
|
+@@ -1794,7 +1808,7 @@ unsigned long unmapped_area(struct vm_unmapped_area_info *info)
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+- gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0;
|
|
|
++ gap_start = vma->vm_prev ? vm_end_gap(vma->vm_prev) : 0;
|
|
|
+ check_current:
|
|
|
+ /* Check if current node has a suitable gap */
|
|
|
+ if (gap_start > high_limit)
|
|
|
+@@ -1821,8 +1835,8 @@ unsigned long unmapped_area(struct vm_unmapped_area_info *info)
|
|
|
+ vma = rb_entry(rb_parent(prev),
|
|
|
+ struct vm_area_struct, vm_rb);
|
|
|
+ if (prev == vma->vm_rb.rb_left) {
|
|
|
+- gap_start = vma->vm_prev->vm_end;
|
|
|
+- gap_end = vma->vm_start;
|
|
|
++ gap_start = vm_end_gap(vma->vm_prev);
|
|
|
++ gap_end = vm_start_gap(vma);
|
|
|
+ goto check_current;
|
|
|
+ }
|
|
|
+ }
|
|
|
+@@ -1886,7 +1900,7 @@ unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info)
|
|
|
+
|
|
|
+ while (true) {
|
|
|
+ /* Visit right subtree if it looks promising */
|
|
|
+- gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0;
|
|
|
++ gap_start = vma->vm_prev ? vm_end_gap(vma->vm_prev) : 0;
|
|
|
+ if (gap_start <= high_limit && vma->vm_rb.rb_right) {
|
|
|
+ struct vm_area_struct *right =
|
|
|
+ rb_entry(vma->vm_rb.rb_right,
|
|
|
+@@ -1899,7 +1913,7 @@ unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info)
|
|
|
+
|
|
|
+ check_current:
|
|
|
+ /* Check if current node has a suitable gap */
|
|
|
+- gap_end = vma->vm_start;
|
|
|
++ gap_end = vm_start_gap(vma);
|
|
|
+ if (gap_end < low_limit)
|
|
|
+ return -ENOMEM;
|
|
|
+ if (gap_start <= high_limit && gap_end - gap_start >= length)
|
|
|
+@@ -1925,7 +1939,7 @@ unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info)
|
|
|
+ struct vm_area_struct, vm_rb);
|
|
|
+ if (prev == vma->vm_rb.rb_right) {
|
|
|
+ gap_start = vma->vm_prev ?
|
|
|
+- vma->vm_prev->vm_end : 0;
|
|
|
++ vm_end_gap(vma->vm_prev) : 0;
|
|
|
+ goto check_current;
|
|
|
+ }
|
|
|
+ }
|
|
|
+@@ -1963,7 +1977,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
|
|
|
+ unsigned long len, unsigned long pgoff, unsigned long flags)
|
|
|
+ {
|
|
|
+ struct mm_struct *mm = current->mm;
|
|
|
+- struct vm_area_struct *vma;
|
|
|
++ struct vm_area_struct *vma, *prev;
|
|
|
+ struct vm_unmapped_area_info info;
|
|
|
+
|
|
|
+ if (len > TASK_SIZE - mmap_min_addr)
|
|
|
+@@ -1974,9 +1988,10 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
|
|
|
+
|
|
|
+ if (addr) {
|
|
|
+ addr = PAGE_ALIGN(addr);
|
|
|
+- vma = find_vma(mm, addr);
|
|
|
++ vma = find_vma_prev(mm, addr, &prev);
|
|
|
+ if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
|
|
|
+- (!vma || addr + len <= vma->vm_start))
|
|
|
++ (!vma || addr + len <= vm_start_gap(vma)) &&
|
|
|
++ (!prev || addr >= vm_end_gap(prev)))
|
|
|
+ return addr;
|
|
|
+ }
|
|
|
+
|
|
|
+@@ -1999,7 +2014,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
|
|
|
+ const unsigned long len, const unsigned long pgoff,
|
|
|
+ const unsigned long flags)
|
|
|
+ {
|
|
|
+- struct vm_area_struct *vma;
|
|
|
++ struct vm_area_struct *vma, *prev;
|
|
|
+ struct mm_struct *mm = current->mm;
|
|
|
+ unsigned long addr = addr0;
|
|
|
+ struct vm_unmapped_area_info info;
|
|
|
+@@ -2014,9 +2029,10 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
|
|
|
+ /* requesting a specific address */
|
|
|
+ if (addr) {
|
|
|
+ addr = PAGE_ALIGN(addr);
|
|
|
+- vma = find_vma(mm, addr);
|
|
|
++ vma = find_vma_prev(mm, addr, &prev);
|
|
|
+ if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
|
|
|
+- (!vma || addr + len <= vma->vm_start))
|
|
|
++ (!vma || addr + len <= vm_start_gap(vma)) &&
|
|
|
++ (!prev || addr >= vm_end_gap(prev)))
|
|
|
+ return addr;
|
|
|
+ }
|
|
|
+
|
|
|
+@@ -2151,21 +2167,19 @@ find_vma_prev(struct mm_struct *mm, unsigned long addr,
|
|
|
+ * update accounting. This is shared with both the
|
|
|
+ * grow-up and grow-down cases.
|
|
|
+ */
|
|
|
+-static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow)
|
|
|
++static int acct_stack_growth(struct vm_area_struct *vma,
|
|
|
++ unsigned long size, unsigned long grow)
|
|
|
+ {
|
|
|
+ struct mm_struct *mm = vma->vm_mm;
|
|
|
+ struct rlimit *rlim = current->signal->rlim;
|
|
|
+- unsigned long new_start, actual_size;
|
|
|
++ unsigned long new_start;
|
|
|
+
|
|
|
+ /* address space limit tests */
|
|
|
+ if (!may_expand_vm(mm, vma->vm_flags, grow))
|
|
|
+ return -ENOMEM;
|
|
|
+
|
|
|
+ /* Stack limit test */
|
|
|
+- actual_size = size;
|
|
|
+- if (size && (vma->vm_flags & (VM_GROWSUP | VM_GROWSDOWN)))
|
|
|
+- actual_size -= PAGE_SIZE;
|
|
|
+- if (actual_size > READ_ONCE(rlim[RLIMIT_STACK].rlim_cur))
|
|
|
++ if (size > READ_ONCE(rlim[RLIMIT_STACK].rlim_cur))
|
|
|
+ return -ENOMEM;
|
|
|
+
|
|
|
+ /* mlock limit tests */
|
|
|
+@@ -2203,17 +2217,30 @@ static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, uns
|
|
|
+ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
|
|
|
+ {
|
|
|
+ struct mm_struct *mm = vma->vm_mm;
|
|
|
++ struct vm_area_struct *next;
|
|
|
++ unsigned long gap_addr;
|
|
|
+ int error = 0;
|
|
|
+
|
|
|
+ if (!(vma->vm_flags & VM_GROWSUP))
|
|
|
+ return -EFAULT;
|
|
|
+
|
|
|
+ /* Guard against wrapping around to address 0. */
|
|
|
+- if (address < PAGE_ALIGN(address+4))
|
|
|
+- address = PAGE_ALIGN(address+4);
|
|
|
+- else
|
|
|
++ address &= PAGE_MASK;
|
|
|
++ address += PAGE_SIZE;
|
|
|
++ if (!address)
|
|
|
+ return -ENOMEM;
|
|
|
+
|
|
|
++ /* Enforce stack_guard_gap */
|
|
|
++ gap_addr = address + stack_guard_gap;
|
|
|
++ if (gap_addr < address)
|
|
|
++ return -ENOMEM;
|
|
|
++ next = vma->vm_next;
|
|
|
++ if (next && next->vm_start < gap_addr) {
|
|
|
++ if (!(next->vm_flags & VM_GROWSUP))
|
|
|
++ return -ENOMEM;
|
|
|
++ /* Check that both stack segments have the same anon_vma? */
|
|
|
++ }
|
|
|
++
|
|
|
+ /* We must make sure the anon_vma is allocated. */
|
|
|
+ if (unlikely(anon_vma_prepare(vma)))
|
|
|
+ return -ENOMEM;
|
|
|
+@@ -2257,7 +2284,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
|
|
|
+ if (vma->vm_next)
|
|
|
+ vma_gap_update(vma->vm_next);
|
|
|
+ else
|
|
|
+- mm->highest_vm_end = address;
|
|
|
++ mm->highest_vm_end = vm_end_gap(vma);
|
|
|
+ spin_unlock(&mm->page_table_lock);
|
|
|
+
|
|
|
+ perf_event_mmap(vma);
|
|
|
+@@ -2278,6 +2305,8 @@ int expand_downwards(struct vm_area_struct *vma,
|
|
|
+ unsigned long address)
|
|
|
+ {
|
|
|
+ struct mm_struct *mm = vma->vm_mm;
|
|
|
++ struct vm_area_struct *prev;
|
|
|
++ unsigned long gap_addr;
|
|
|
+ int error;
|
|
|
+
|
|
|
+ address &= PAGE_MASK;
|
|
|
+@@ -2285,6 +2314,17 @@ int expand_downwards(struct vm_area_struct *vma,
|
|
|
+ if (error)
|
|
|
+ return error;
|
|
|
+
|
|
|
++ /* Enforce stack_guard_gap */
|
|
|
++ gap_addr = address - stack_guard_gap;
|
|
|
++ if (gap_addr > address)
|
|
|
++ return -ENOMEM;
|
|
|
++ prev = vma->vm_prev;
|
|
|
++ if (prev && prev->vm_end > gap_addr) {
|
|
|
++ if (!(prev->vm_flags & VM_GROWSDOWN))
|
|
|
++ return -ENOMEM;
|
|
|
++ /* Check that both stack segments have the same anon_vma? */
|
|
|
++ }
|
|
|
++
|
|
|
+ /* We must make sure the anon_vma is allocated. */
|
|
|
+ if (unlikely(anon_vma_prepare(vma)))
|
|
|
+ return -ENOMEM;
|
|
|
+@@ -2339,28 +2379,25 @@ int expand_downwards(struct vm_area_struct *vma,
|
|
|
+ return error;
|
|
|
+ }
|
|
|
+
|
|
|
+-/*
|
|
|
+- * Note how expand_stack() refuses to expand the stack all the way to
|
|
|
+- * abut the next virtual mapping, *unless* that mapping itself is also
|
|
|
+- * a stack mapping. We want to leave room for a guard page, after all
|
|
|
+- * (the guard page itself is not added here, that is done by the
|
|
|
+- * actual page faulting logic)
|
|
|
+- *
|
|
|
+- * This matches the behavior of the guard page logic (see mm/memory.c:
|
|
|
+- * check_stack_guard_page()), which only allows the guard page to be
|
|
|
+- * removed under these circumstances.
|
|
|
+- */
|
|
|
++/* enforced gap between the expanding stack and other mappings. */
|
|
|
++unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT;
|
|
|
++
|
|
|
++static int __init cmdline_parse_stack_guard_gap(char *p)
|
|
|
++{
|
|
|
++ unsigned long val;
|
|
|
++ char *endptr;
|
|
|
++
|
|
|
++ val = simple_strtoul(p, &endptr, 10);
|
|
|
++ if (!*endptr)
|
|
|
++ stack_guard_gap = val << PAGE_SHIFT;
|
|
|
++
|
|
|
++ return 0;
|
|
|
++}
|
|
|
++__setup("stack_guard_gap=", cmdline_parse_stack_guard_gap);
|
|
|
++
|
|
|
+ #ifdef CONFIG_STACK_GROWSUP
|
|
|
+ int expand_stack(struct vm_area_struct *vma, unsigned long address)
|
|
|
+ {
|
|
|
+- struct vm_area_struct *next;
|
|
|
+-
|
|
|
+- address &= PAGE_MASK;
|
|
|
+- next = vma->vm_next;
|
|
|
+- if (next && next->vm_start == address + PAGE_SIZE) {
|
|
|
+- if (!(next->vm_flags & VM_GROWSUP))
|
|
|
+- return -ENOMEM;
|
|
|
+- }
|
|
|
+ return expand_upwards(vma, address);
|
|
|
+ }
|
|
|
+
|
|
|
+@@ -2382,14 +2419,6 @@ find_extend_vma(struct mm_struct *mm, unsigned long addr)
|
|
|
+ #else
|
|
|
+ int expand_stack(struct vm_area_struct *vma, unsigned long address)
|
|
|
+ {
|
|
|
+- struct vm_area_struct *prev;
|
|
|
+-
|
|
|
+- address &= PAGE_MASK;
|
|
|
+- prev = vma->vm_prev;
|
|
|
+- if (prev && prev->vm_end == address) {
|
|
|
+- if (!(prev->vm_flags & VM_GROWSDOWN))
|
|
|
+- return -ENOMEM;
|
|
|
+- }
|
|
|
+ return expand_downwards(vma, address);
|
|
|
+ }
|
|
|
+
|
|
|
+@@ -2487,7 +2516,7 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
|
|
|
+ vma->vm_prev = prev;
|
|
|
+ vma_gap_update(vma);
|
|
|
+ } else
|
|
|
+- mm->highest_vm_end = prev ? prev->vm_end : 0;
|
|
|
++ mm->highest_vm_end = prev ? vm_end_gap(prev) : 0;
|
|
|
+ tail_vma->vm_next = NULL;
|
|
|
+
|
|
|
+ /* Kill the cache */
|
|
|
+--
|
|
|
+2.11.0
|
|
|
+
|
Fabian Grünbichler