4.14-stable review patch. If anyone has any objections, please let me know.
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From: Mikulas Patocka mpatocka@redhat.com
commit 9f586fff6574f6ecbf323f92d44ffaf0d96225fe upstream.
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
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/dax/super.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -344,6 +344,9 @@ static struct inode *dax_alloc_inode(str 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;