From ab27a8d04b32b6ee8c30c14c4afd1058e8addc82 Mon Sep 17 00:00:00 2001
From: Ross Zwisler <ross.zwisler@linux.intel.com>
Date: Mon, 5 Oct 2015 16:33:37 -0600
Subject: coredump: add DAX filtering for FDPIC ELF coredumps

Add explicit filtering for DAX mappings to FDPIC ELF coredump.  This is
useful because DAX mappings have the potential to be very large.

This patch has only been compile tested.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index d3634bf..8632501 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -35,6 +35,7 @@
 #include <linux/elf-fdpic.h>
 #include <linux/elfcore.h>
 #include <linux/coredump.h>
+#include <linux/dax.h>
 
 #include <asm/uaccess.h>
 #include <asm/param.h>
@@ -1206,6 +1207,20 @@ static int maydump(struct vm_area_struct *vma, unsigned long mm_flags)
 		return 0;
 	}
 
+	/* support for DAX */
+	if (vma_is_dax(vma)) {
+		if (vma->vm_flags & VM_SHARED) {
+			dump_ok = test_bit(MMF_DUMP_DAX_SHARED, &mm_flags);
+			kdcore("%08lx: %08lx: %s (DAX shared)", vma->vm_start,
+			       vma->vm_flags, dump_ok ? "yes" : "no");
+		} else {
+			dump_ok = test_bit(MMF_DUMP_DAX_PRIVATE, &mm_flags);
+			kdcore("%08lx: %08lx: %s (DAX private)", vma->vm_start,
+			       vma->vm_flags, dump_ok ? "yes" : "no");
+		}
+		return dump_ok;
+	}
+
 	/* By default, dump shared memory if mapped from an anonymous file. */
 	if (vma->vm_flags & VM_SHARED) {
 		if (file_inode(vma->vm_file)->i_nlink == 0) {
-- 
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