syzbot


UBSAN: undefined-behaviour in sfq_init

Status: upstream: reported C repro on 2020/09/25 07:12
Reported-by: syzbot+1740758b3d1332c875c2@syzkaller.appspotmail.com
First crash: 1280d, last: 1258d
Fix bisection: failed (error log, bisect log)
  

Sample crash report:
audit: type=1400 audit(1602918494.933:8): avc:  denied  { execmem } for  pid=6489 comm="syz-executor243" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process permissive=1
================================================================================
UBSAN: Undefined behaviour in ./include/net/red.h:214:22
shift exponent 147 is too large for 32-bit type 'int'
CPU: 0 PID: 6489 Comm: syz-executor243 Not tainted 4.19.150-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x22c/0x33e lib/dump_stack.c:118
 ubsan_epilogue+0xe/0x3a lib/ubsan.c:161
 __ubsan_handle_shift_out_of_bounds.cold+0x1c4/0x250 lib/ubsan.c:422
 red_set_parms include/net/red.h:214 [inline]
 sfq_change net/sched/sch_sfq.c:678 [inline]
 sfq_init.cold+0x8f/0xdb net/sched/sch_sfq.c:766
 qdisc_create+0x534/0x1080 net/sched/sch_api.c:1155
 tc_modify_qdisc+0x4c0/0x195b net/sched/sch_api.c:1571
 rtnetlink_rcv_msg+0x498/0xc10 net/core/rtnetlink.c:4778
 netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2455
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x717/0xcc0 net/netlink/af_netlink.c:1909
 sock_sendmsg_nosec net/socket.c:622 [inline]
 sock_sendmsg+0xc7/0x130 net/socket.c:632
 ___sys_sendmsg+0x7bb/0x8f0 net/socket.c:2115
 __sys_sendmsg net/socket.c:2153 [inline]
 __do_sys_sendmsg net/socket.c:2162 [inline]
 __se_sys_sendmsg net/socket.c:2160 [inline]
 __x64_sys_sendmsg+0x132/0x220 net/socket.c:2160
 do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440419
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 7b 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fff49be6948 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 000000000

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/10/17 07:09 linux-4.19.y a1b977b49b66 6e262c73 .config console log report syz C ci2-linux-4-19
2020/09/25 07:30 linux-4.19.y d09b80172c22 54289b08 .config console log report syz C ci2-linux-4-19
2020/09/25 07:11 linux-4.19.y d09b80172c22 54289b08 .config console log report info ci2-linux-4-19
* Struck through repros no longer work on HEAD.