Hillf Danton <hdanton@xxxxxxxx> writes: >> syzbot has found a reproducer for the following crash on Sat, 07 Sep 2019 18:59:06 -0700 >> >> HEAD commit: a2c11b03 kcm: use BPF_PROG_RUN >> git tree: bpf-next >> console output: https://syzkaller.appspot.com/x/log.txt?x=13d46ec1600000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=cf0c85d15c20ade3 >> dashboard link: https://syzkaller.appspot.com/bug?extid=4e7a85b1432052e8d6f8 >> compiler: gcc (GCC) 9.0.0 20181231 (experimental) >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1220b2d1600000 >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1360b26e600000 >> >> general protection fault: 0000 [#1] PREEMPT SMP KASAN >> CPU: 1 PID: 10210 Comm: syz-executor910 Not tainted 5.3.0-rc7+ #0 >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >> Google 01/01/2011 >> RIP: 0010:__write_once_size include/linux/compiler.h:226 [inline] >> RIP: 0010:__hlist_del include/linux/list.h:762 [inline] >> RIP: 0010:hlist_del_rcu include/linux/rculist.h:455 [inline] >> RIP: 0010:__dev_map_hash_update_elem kernel/bpf/devmap.c:668 [inline] >> RIP: 0010:dev_map_hash_update_elem+0x3c8/0x6e0 kernel/bpf/devmap.c:691 > > Fix commit 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking > up devices by hashed index") While this minimal patch does fix the bug (as Jesper already noted), I prefer to rework the logic instead of just repeating the lookup; a patch is on its way :) -Toke
