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-rw-r--r--arch/alpha/include/uapi/asm/mman.h3
-rw-r--r--arch/mips/include/uapi/asm/mman.h3
-rw-r--r--arch/parisc/include/uapi/asm/mman.h3
-rw-r--r--arch/xtensa/include/uapi/asm/mman.h3
-rw-r--r--fs/proc/task_mmu.c1
-rw-r--r--include/linux/mm.h2
-rw-r--r--include/trace/events/mmflags.h8
-rw-r--r--include/uapi/asm-generic/mman-common.h3
-rw-r--r--kernel/fork.c10
-rw-r--r--mm/madvise.c13
10 files changed, 39 insertions, 10 deletions
diff --git a/arch/alpha/include/uapi/asm/mman.h b/arch/alpha/include/uapi/asm/mman.h
index 13b52aa..3b26cc6 100644
--- a/arch/alpha/include/uapi/asm/mman.h
+++ b/arch/alpha/include/uapi/asm/mman.h
@@ -64,6 +64,9 @@
overrides the coredump filter bits */
#define MADV_DODUMP 17 /* Clear the MADV_NODUMP flag */
+#define MADV_WIPEONFORK 18 /* Zero memory on fork, child only */
+#define MADV_KEEPONFORK 19 /* Undo MADV_WIPEONFORK */
+
/* compatibility flags */
#define MAP_FILE 0
diff --git a/arch/mips/include/uapi/asm/mman.h b/arch/mips/include/uapi/asm/mman.h
index 398eebc..da32160 100644
--- a/arch/mips/include/uapi/asm/mman.h
+++ b/arch/mips/include/uapi/asm/mman.h
@@ -91,6 +91,9 @@
overrides the coredump filter bits */
#define MADV_DODUMP 17 /* Clear the MADV_NODUMP flag */
+#define MADV_WIPEONFORK 18 /* Zero memory on fork, child only */
+#define MADV_KEEPONFORK 19 /* Undo MADV_WIPEONFORK */
+
/* compatibility flags */
#define MAP_FILE 0
diff --git a/arch/parisc/include/uapi/asm/mman.h b/arch/parisc/include/uapi/asm/mman.h
index b87fbe3..775b5d5 100644
--- a/arch/parisc/include/uapi/asm/mman.h
+++ b/arch/parisc/include/uapi/asm/mman.h
@@ -57,6 +57,9 @@
overrides the coredump filter bits */
#define MADV_DODUMP 70 /* Clear the MADV_NODUMP flag */
+#define MADV_WIPEONFORK 71 /* Zero memory on fork, child only */
+#define MADV_KEEPONFORK 72 /* Undo MADV_WIPEONFORK */
+
#define MADV_HWPOISON 100 /* poison a page for testing */
#define MADV_SOFT_OFFLINE 101 /* soft offline page for testing */
diff --git a/arch/xtensa/include/uapi/asm/mman.h b/arch/xtensa/include/uapi/asm/mman.h
index 8ce77a2..b15b278 100644
--- a/arch/xtensa/include/uapi/asm/mman.h
+++ b/arch/xtensa/include/uapi/asm/mman.h
@@ -103,6 +103,9 @@
overrides the coredump filter bits */
#define MADV_DODUMP 17 /* Clear the MADV_NODUMP flag */
+#define MADV_WIPEONFORK 18 /* Zero memory on fork, child only */
+#define MADV_KEEPONFORK 19 /* Undo MADV_WIPEONFORK */
+
/* compatibility flags */
#define MAP_FILE 0
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index b2330ae..a290966 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -663,6 +663,7 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
[ilog2(VM_NORESERVE)] = "nr",
[ilog2(VM_HUGETLB)] = "ht",
[ilog2(VM_ARCH_1)] = "ar",
+ [ilog2(VM_WIPEONFORK)] = "wf",
[ilog2(VM_DONTDUMP)] = "dd",
#ifdef CONFIG_MEM_SOFT_DIRTY
[ilog2(VM_SOFTDIRTY)] = "sd",
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 9efe620..39db8e5 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -189,7 +189,7 @@ extern unsigned int kobjsize(const void *objp);
#define VM_NORESERVE 0x00200000 /* should the VM suppress accounting */
#define VM_HUGETLB 0x00400000 /* Huge TLB Page VM */
#define VM_ARCH_1 0x01000000 /* Architecture-specific flag */
-#define VM_ARCH_2 0x02000000
+#define VM_WIPEONFORK 0x02000000 /* Wipe VMA contents in child. */
#define VM_DONTDUMP 0x04000000 /* Do not include in the core dump */
#ifdef CONFIG_MEM_SOFT_DIRTY
diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h
index 8e50d01..4c2e473 100644
--- a/include/trace/events/mmflags.h
+++ b/include/trace/events/mmflags.h
@@ -125,12 +125,6 @@ IF_HAVE_PG_IDLE(PG_idle, "idle" )
#define __VM_ARCH_SPECIFIC_1 {VM_ARCH_1, "arch_1" }
#endif
-#if defined(CONFIG_X86)
-#define __VM_ARCH_SPECIFIC_2 {VM_MPX, "mpx" }
-#else
-#define __VM_ARCH_SPECIFIC_2 {VM_ARCH_2, "arch_2" }
-#endif
-
#ifdef CONFIG_MEM_SOFT_DIRTY
#define IF_HAVE_VM_SOFTDIRTY(flag,name) {flag, name },
#else
@@ -162,7 +156,7 @@ IF_HAVE_PG_IDLE(PG_idle, "idle" )
{VM_NORESERVE, "noreserve" }, \
{VM_HUGETLB, "hugetlb" }, \
__VM_ARCH_SPECIFIC_1 , \
- __VM_ARCH_SPECIFIC_2 , \
+ {VM_WIPEONFORK, "wipeonfork" }, \
{VM_DONTDUMP, "dontdump" }, \
IF_HAVE_VM_SOFTDIRTY(VM_SOFTDIRTY, "softdirty" ) \
{VM_MIXEDMAP, "mixedmap" }, \
diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h
index d248f3c..203268f 100644
--- a/include/uapi/asm-generic/mman-common.h
+++ b/include/uapi/asm-generic/mman-common.h
@@ -58,6 +58,9 @@
overrides the coredump filter bits */
#define MADV_DODUMP 17 /* Clear the MADV_DONTDUMP flag */
+#define MADV_WIPEONFORK 18 /* Zero memory on fork, child only */
+#define MADV_KEEPONFORK 19 /* Undo MADV_WIPEONFORK */
+
/* compatibility flags */
#define MAP_FILE 0
diff --git a/kernel/fork.c b/kernel/fork.c
index 7ed6460..24a4c0b 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -657,7 +657,12 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
retval = dup_userfaultfd(tmp, &uf);
if (retval)
goto fail_nomem_anon_vma_fork;
- if (anon_vma_fork(tmp, mpnt))
+ if (tmp->vm_flags & VM_WIPEONFORK) {
+ /* VM_WIPEONFORK gets a clean slate in the child. */
+ tmp->anon_vma = NULL;
+ if (anon_vma_prepare(tmp))
+ goto fail_nomem_anon_vma_fork;
+ } else if (anon_vma_fork(tmp, mpnt))
goto fail_nomem_anon_vma_fork;
tmp->vm_flags &= ~(VM_LOCKED | VM_LOCKONFAULT);
tmp->vm_next = tmp->vm_prev = NULL;
@@ -701,7 +706,8 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
rb_parent = &tmp->vm_rb;
mm->map_count++;
- retval = copy_page_range(mm, oldmm, mpnt);
+ if (!(tmp->vm_flags & VM_WIPEONFORK))
+ retval = copy_page_range(mm, oldmm, mpnt);
if (tmp->vm_ops && tmp->vm_ops->open)
tmp->vm_ops->open(tmp);
diff --git a/mm/madvise.c b/mm/madvise.c
index 4d7d1e5..eea1c73 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -80,6 +80,17 @@ static long madvise_behavior(struct vm_area_struct *vma,
}
new_flags &= ~VM_DONTCOPY;
break;
+ case MADV_WIPEONFORK:
+ /* MADV_WIPEONFORK is only supported on anonymous memory. */
+ if (vma->vm_file || vma->vm_flags & VM_SHARED) {
+ error = -EINVAL;
+ goto out;
+ }
+ new_flags |= VM_WIPEONFORK;
+ break;
+ case MADV_KEEPONFORK:
+ new_flags &= ~VM_WIPEONFORK;
+ break;
case MADV_DONTDUMP:
new_flags |= VM_DONTDUMP;
break;
@@ -696,6 +707,8 @@ madvise_behavior_valid(int behavior)
#endif
case MADV_DONTDUMP:
case MADV_DODUMP:
+ case MADV_WIPEONFORK:
+ case MADV_KEEPONFORK:
#ifdef CONFIG_MEMORY_FAILURE
case MADV_SOFT_OFFLINE:
case MADV_HWPOISON:
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