The patch titled
ksm: don't allow overlap memory addresses registrations
has been added to the -mm tree. Its filename is
ksm-add-ksm-kernel-shared-memory-driver-dont-allow-overlap-memory-addresses-registrations.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: ksm: don't allow overlap memory addresses registrations
From: Izik Eidus <ieidus@xxxxxxxxxx>
subjects say it all.
Signed-off-by: Izik Eidus <ieidus@xxxxxxxxxx>
Cc: Chris Wright <chrisw@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Avi Kivity <avi@xxxxxxxxxx>
Cc: Hugh Dickins <hugh@xxxxxxxxxxx>
Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/ksm.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 54 insertions(+), 4 deletions(-)
diff -puN mm/ksm.c~ksm-add-ksm-kernel-shared-memory-driver-dont-allow-overlap-memory-addresses-registrations mm/ksm.c
--- a/mm/ksm.c~ksm-add-ksm-kernel-shared-memory-driver-dont-allow-overlap-memory-addresses-registrations
+++ a/mm/ksm.c
@@ -450,21 +450,71 @@ static void remove_page_from_tree(struct
remove_rmap_item_from_tree(rmap_item);
}
+static inline int is_intersecting_address(unsigned long addr,
+ unsigned long begin,
+ unsigned long end)
+{
+ if (addr >= begin && addr < end)
+ return 1;
+ return 0;
+}
+
+/*
+ * is_overlap_mem - check if there is overlapping with memory that was already
+ * registred.
+ *
+ * note - this function must to be called under slots_lock
+ */
+static int is_overlap_mem(struct ksm_memory_region *mem)
+{
+ struct ksm_mem_slot *slot;
+
+ list_for_each_entry(slot, &slots, link) {
+ unsigned long mem_end;
+ unsigned long slot_end;
+
+ cond_resched();
+
+ if (current->mm != slot->mm)
+ continue;
+
+ mem_end = mem->addr + (unsigned long)mem->npages * PAGE_SIZE;
+ slot_end = slot->addr + (unsigned long)slot->npages * PAGE_SIZE;
+
+ if (is_intersecting_address(mem->addr, slot->addr, slot_end) ||
+ is_intersecting_address(mem_end - 1, slot->addr, slot_end))
+ return 1;
+ if (is_intersecting_address(slot->addr, mem->addr, mem_end) ||
+ is_intersecting_address(slot_end - 1, mem->addr, mem_end))
+ return 1;
+ }
+
+ return 0;
+}
+
static int ksm_sma_ioctl_register_memory_region(struct ksm_sma *ksm_sma,
struct ksm_memory_region *mem)
{
struct ksm_mem_slot *slot;
int ret = -EPERM;
+ if (!mem->npages)
+ goto out;
+
+ down_write(&slots_lock);
+
if ((ksm_sma->nregions + 1) > regions_per_fd) {
ret = -EBUSY;
- goto out;
+ goto out_unlock;
}
+ if (is_overlap_mem(mem))
+ goto out_unlock;
+
slot = kzalloc(sizeof(struct ksm_mem_slot), GFP_KERNEL);
if (!slot) {
ret = -ENOMEM;
- goto out;
+ goto out_unlock;
}
/*
@@ -477,8 +527,6 @@ static int ksm_sma_ioctl_register_memory
slot->addr = mem->addr;
slot->npages = mem->npages;
- down_write(&slots_lock);
-
list_add_tail(&slot->link, &slots);
list_add_tail(&slot->sma_link, &ksm_sma->sma_slots);
ksm_sma->nregions++;
@@ -488,6 +536,8 @@ static int ksm_sma_ioctl_register_memory
out_free:
kfree(slot);
+out_unlock:
+ up_write(&slots_lock);
out:
return ret;
}
_
Patches currently in -mm which might be from ieidus@xxxxxxxxxx are
linux-next.patch
ksm-mmu_notifiers-add-set_pte_at_notify.patch
ksm-add-get_pte-helper-function-fetching-pte-for-va.patch
ksm-add-get_pte-helper-function-fetching-pte-for-va-fix.patch
ksm-add-page_wrprotect-write-protecting-page.patch
ksm-add-replace_page-change-the-page-pte-is-pointing-to.patch
ksm-add-ksm-kernel-shared-memory-driver.patch
ksm-add-ksm-kernel-shared-memory-driver-checkpatch-fixes.patch
ksm-add-ksm-kernel-shared-memory-driver-fix-unsafe-pte-fetching.patch
ksm-add-ksm-kernel-shared-memory-driver-fix.patch
ksm-add-ksm-kernel-shared-memory-driver-limiting-the-num-of-mem-regions-user-can-register-per-fd.patch
ksm-add-ksm-kernel-shared-memory-driver-dont-allow-overlap-memory-addresses-registrations.patch
ksm-add-ksm-kernel-shared-memory-driver-change-the-ksm_remove_memory_region-ioctl.patch
ksm-add-ksm-kernel-shared-memory-driver-change-the-prot-handling-to-use-the-generic-helper-functions.patch
ksm-add-ksm-kernel-shared-memory-driver-use-another-miscdevice-minor-number.patch
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