Commit-ID: af0d95af79773f7637107cd3871aaabcb425f15a
Gitweb: http://git.kernel.org/tip/af0d95af79773f7637107cd3871aaabcb425f15a
Author: Oleg Nesterov <oleg@xxxxxxxxxx>
AuthorDate: Sun, 13 Oct 2013 21:18:38 +0200
Committer: Oleg Nesterov <oleg@xxxxxxxxxx>
CommitDate: Tue, 29 Oct 2013 18:02:51 +0100
uprobes: Teach __create_xol_area() to accept the predefined vaddr
Currently xol_add_vma() uses get_unmapped_area() for area->vaddr,
but the next patches need to use the fixed address. So this patch
adds the new "vaddr" argument to __create_xol_area() which should
be used as area->vaddr if it is nonzero.
xol_add_vma() doesn't bother to verify that the predefined addr is
not used, insert_vm_struct() should fail if find_vma_links() detects
the overlap with the existing vma.
Also, __create_xol_area() doesn't need __GFP_ZERO to allocate area.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
---
kernel/events/uprobes.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index ad17d81..7d12a45 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1104,11 +1104,14 @@ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area)
if (mm->uprobes_state.xol_area)
goto fail;
- /* Try to map as high as possible, this is only a hint. */
- area->vaddr = get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE, PAGE_SIZE, 0, 0);
- if (area->vaddr & ~PAGE_MASK) {
- ret = area->vaddr;
- goto fail;
+ if (!area->vaddr) {
+ /* Try to map as high as possible, this is only a hint. */
+ area->vaddr = get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE,
+ PAGE_SIZE, 0, 0);
+ if (area->vaddr & ~PAGE_MASK) {
+ ret = area->vaddr;
+ goto fail;
+ }
}
ret = install_special_mapping(mm, area->vaddr, PAGE_SIZE,
@@ -1124,13 +1127,13 @@ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area)
return ret;
}
-static struct xol_area *__create_xol_area(void)
+static struct xol_area *__create_xol_area(unsigned long vaddr)
{
struct mm_struct *mm = current->mm;
uprobe_opcode_t insn = UPROBE_SWBP_INSN;
struct xol_area *area;
- area = kzalloc(sizeof(*area), GFP_KERNEL);
+ area = kmalloc(sizeof(*area), GFP_KERNEL);
if (unlikely(!area))
goto out;
@@ -1142,6 +1145,7 @@ static struct xol_area *__create_xol_area(void)
if (!area->page)
goto free_bitmap;
+ area->vaddr = vaddr;
init_waitqueue_head(&area->wq);
/* Reserve the 1st slot for get_trampoline_vaddr() */
set_bit(0, area->bitmap);
@@ -1172,7 +1176,7 @@ static struct xol_area *get_xol_area(void)
struct xol_area *area;
if (!mm->uprobes_state.xol_area)
- __create_xol_area();
+ __create_xol_area(0);
area = mm->uprobes_state.xol_area;
smp_read_barrier_depends(); /* pairs with wmb in xol_add_vma() */
--
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