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authorMikulas Patocka <mpatocka@redhat.com>2017-11-14 09:59:54 -0500
committerDan Williams <dan.j.williams@intel.com>2017-11-14 23:48:42 -0800
commit9f586fff6574f6ecbf323f92d44ffaf0d96225fe (patch)
tree1192f55e600606c93d45424157efc5c973024a22 /drivers/dax
parent957ac8c421ad8b5eef9b17fe98e146d8311a541e (diff)
downloadlinux-9f586fff6574f6ecbf323f92d44ffaf0d96225fe.tar.gz
dax: fix general protection fault in dax_alloc_inode
Don't crash in case of allocation failure in dax_alloc_inode.

    syzkaller hit the following crash on e4880bc5dfb1

    kasan: CONFIG_KASAN_INLINE enabled
    kasan: GPF could be caused by NULL-ptr deref or user memory access
    [..]
    RIP: 0010:dax_alloc_inode+0x3b/0x70 drivers/dax/super.c:348
    Call Trace:
    alloc_inode+0x65/0x180 fs/inode.c:208
    new_inode_pseudo+0x69/0x190 fs/inode.c:890
    new_inode+0x1c/0x40 fs/inode.c:919
    mount_pseudo_xattr+0x288/0x560 fs/libfs.c:261
    mount_pseudo include/linux/fs.h:2137 [inline]
    dax_mount+0x2e/0x40 drivers/dax/super.c:388
    mount_fs+0x66/0x2d0 fs/super.c:1223

Cc: <stable@vger.kernel.org>
Fixes: 7b6be8444e0f ("dax: refactor dax-fs into a generic provider...")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/dax')
-rw-r--r--drivers/dax/super.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 69329e3954ea..3ec804672601 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -341,6 +341,9 @@ static struct inode *dax_alloc_inode(struct super_block *sb)
 	struct inode *inode;
 
 	dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL);
+	if (!dax_dev)
+		return NULL;
+
 	inode = &dax_dev->inode;
 	inode->i_rdev = 0;
 	return inode;