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authorMikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>2011-05-09 13:01:09 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2011-05-09 16:22:07 -0700
commita09a79f66874c905af35d5bb5e5f2fdc7b6b894d (patch)
tree9cb2ae1fef7083af91a49c19411e9871e0e59a37 /fs
parent26822eebb25500fb0776c7c256a6af041e9f538b (diff)
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Don't lock guardpage if the stack is growing up
Linux kernel excludes guard page when performing mlock on a VMA with down-growing stack. However, some architectures have up-growing stack and locking the guard page should be excluded in this case too. This patch fixes lvm2 on PA-RISC (and possibly other architectures with up-growing stack). lvm2 calculates number of used pages when locking and when unlocking and reports an internal error if the numbers mismatch. [ Patch changed fairly extensively to also fix /proc/<pid>/maps for the grows-up case, and to move things around a bit to clean it all up and share the infrstructure with the /proc bits. Tested on ia64 that has both grow-up and grow-down segments - Linus ] Signed-off-by: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> Tested-by: Tony Luck <tony.luck@gmail.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/proc/task_mmu.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 2e7addf..318d865 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -214,7 +214,7 @@ static void show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
int flags = vma->vm_flags;
unsigned long ino = 0;
unsigned long long pgoff = 0;
- unsigned long start;
+ unsigned long start, end;
dev_t dev = 0;
int len;
@@ -227,13 +227,15 @@ static void show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
/* We don't show the stack guard page in /proc/maps */
start = vma->vm_start;
- if (vma->vm_flags & VM_GROWSDOWN)
- if (!vma_stack_continue(vma->vm_prev, vma->vm_start))
- start += PAGE_SIZE;
+ 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_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu %n",
start,
- vma->vm_end,
+ end,
flags & VM_READ ? 'r' : '-',
flags & VM_WRITE ? 'w' : '-',
flags & VM_EXEC ? 'x' : '-',