Commit 9f586fff authored Nov 14, 2017 by Mikulas Patocka Committed by Dan Williams Nov 14, 2017

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 e4880bc5

    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: 7b6be844 ("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>

parent 957ac8c4

drivers/dax/super.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -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;

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