On Wed, Jul 24, 2019 at 4:17 PM Oliver Neukum <oneukum@xxxxxxxx> wrote: > > Am Dienstag, den 23.07.2019, 05:48 -0700 schrieb syzbot: > > > > Freed by task 243: > > save_stack+0x1b/0x80 /mm/kasan/common.c:71 > > set_track /mm/kasan/common.c:79 [inline] > > __kasan_slab_free+0x130/0x180 /mm/kasan/common.c:451 > > slab_free_hook /mm/slub.c:1421 [inline] > > slab_free_freelist_hook /mm/slub.c:1448 [inline] > > slab_free /mm/slub.c:2994 [inline] > > kfree+0xd7/0x280 /mm/slub.c:3949 > > skb_free_head+0x8b/0xa0 /net/core/skbuff.c:588 > > skb_release_data+0x41f/0x7c0 /net/core/skbuff.c:608 > > skb_release_all+0x46/0x60 /net/core/skbuff.c:662 > > __kfree_skb /net/core/skbuff.c:676 [inline] > > consume_skb /net/core/skbuff.c:736 [inline] > > consume_skb+0xc0/0x2f0 /net/core/skbuff.c:730 > > skb_free_datagram+0x16/0xf0 /net/core/datagram.c:328 > > netlink_recvmsg+0x65e/0xea0 /net/netlink/af_netlink.c:2001 > > sock_recvmsg_nosec /net/socket.c:877 [inline] > > sock_recvmsg /net/socket.c:894 [inline] > > sock_recvmsg+0xca/0x110 /net/socket.c:890 > > ___sys_recvmsg+0x271/0x5a0 /net/socket.c:2448 > > __sys_recvmsg+0xe9/0x1b0 /net/socket.c:2497 > > do_syscall_64+0xb7/0x560 /arch/x86/entry/common.c:301 > > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > How reliable is this trace? It seems very likely to me that this bug > is the same bug as > > syzbot <syzbot+ded1794a717e3b235226@xxxxxxxxxxxxxxxxxxxxxxxxx> > KASAN: use-after-free Read in hidraw_ioctl > > which shows a race with disconnect() instead of some networking code, > which I really cannot fathom. To me the alloc/free stack trace doesn't seem to have anything to do with the access stack trace here, so I wouldn't rely on them. This is a limitation of KASAN and can happen when there's a wild memory access or a huge out-of-bounds or some kind of a racy-use-after-free. > > Regards > Oliver >
