On Thu, Sep 12, 2019 at 12:25:10PM -0700, Zubin Mithra wrote:

Hello,

Syzkaller has triggered a WARNING in packet_set_ring when fuzzing a 4.4 kernel with the following stacktrace. Call Trace: __dump_stack lib/dump_stack.c:15 [inline] dump_stack+0xc1/0x124 lib/dump_stack.c:51 panic+0x1a7/0x351 kernel/panic.c:115 warn_slowpath_common+0x12a/0x140 kernel/panic.c:463 warn_slowpath_fmt+0xb0/0xe0 kernel/panic.c:479 packet_set_ring+0x13ed/0x19c0 net/packet/af_packet.c:4104 packet_setsockopt+0x53e/0x21d0 net/packet/af_packet.c:3578 SYSC_setsockopt net/socket.c:1766 [inline] SyS_setsockopt+0x15d/0x240 net/socket.c:1745 entry_SYSCALL_64_fastpath+0x12/0x72

Could the following patch be applied in v4.4.y? It is present in v4.9.y. Applying this patch could allow the fuzzer to explore more codepaths.

• 6ae81ced3788 ("af_packet: tone down the Tx-ring unsupported spew.")

Queued up for 4.4, thank you.

-- Thanks, Sasha