Hello, syzbot found the following issue on:
HEAD commit: 71c5f031 Merge tag 'docs-5.11-2' of git://git.lwn.net/linux git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=15103693500000 kernel config: https://syzkaller.appspot.com/x/.config?x=3e7e34a83d606100 dashboard link: https://syzkaller.appspot.com/bug?extid=4eda8c01ca2315d1722e compiler: gcc (GCC) 10.1.0-syz 20200507 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=143d33ff500000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13725277500000 Bisection is inconclusive: the issue happens on the oldest tested release. bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=137f60db500000 final oops: https://syzkaller.appspot.com/x/report.txt?x=10ff60db500000 console output: https://syzkaller.appspot.com/x/log.txt?x=177f60db500000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+4eda8c01ca2315d17...@syzkaller.appspotmail.com netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0 netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0 netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0 ================================================================================ UBSAN: shift-out-of-bounds in ./include/net/red.h:252:22 shift exponent 96 is too large for 32-bit type 'int' CPU: 0 PID: 8513 Comm: syz-executor800 Not tainted 5.10.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 ubsan_epilogue+0xb/0x5a lib/ubsan.c:148 __ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:395 red_set_parms include/net/red.h:252 [inline] choke_change.cold+0xce/0x115 net/sched/sch_choke.c:413 qdisc_create+0x4ba/0x13a0 net/sched/sch_api.c:1246 tc_modify_qdisc+0x4c8/0x1a30 net/sched/sch_api.c:1662 rtnetlink_rcv_msg+0x498/0xb80 net/core/rtnetlink.c:5564 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330 netlink_sendmsg+0x907/0xe40 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:672 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2345 ___sys_sendmsg+0xf3/0x170 net/socket.c:2399 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2432 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x4437b9 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb 0d fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fff205ca1d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004437b9 RDX: 0000000000000000 RSI: 00000000200007c0 RDI: 0000000000000004 RBP: 00007fff205ca1e0 R08: 0000000001bbbbbb R09: 0000000001bbbbbb R10: 0000000001bbbbbb R11: 0000000000000246 R12: 00007fff205ca1f0 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ================================================================================ --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkal...@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches
