syzbot


WARNING: suspicious RCU usage in ipmr_rtm_dumplink

Status: internal: reported on 2022/06/25 01:51
Reported-by: syzbot+@syzkaller.appspotmail.com
Fix commit: 0fcae3c8b1b3 ipmr: fix a lockdep splat in ipmr_rtm_dumplink()
Patched on: [ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce ci-upstream-kmsan-gce-386 ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb], missing on: [ci-qemu2-riscv64]
First crash: 225d, last: 222d

Sample crash report:
=============================
WARNING: suspicious RCU usage
5.19.0-rc3-syzkaller-00590-gc83bc86a0596 #0 Not tainted
-----------------------------
net/ipv4/ipmr.c:84 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
1 lock held by syz-executor.5/16785:
 #0: ffffffff8d5911a8 (rtnl_mutex){+.+.}-{3:3}, at: netlink_dump+0xae/0xc20 net/netlink/af_netlink.c:2223

stack backtrace:
CPU: 0 PID: 16785 Comm: syz-executor.5 Not tainted 5.19.0-rc3-syzkaller-00590-gc83bc86a0596 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 vif_dev_read net/ipv4/ipmr.c:84 [inline]
 vif_dev_read net/ipv4/ipmr.c:82 [inline]
 ipmr_fill_vif net/ipv4/ipmr.c:2756 [inline]
 ipmr_rtm_dumplink+0x1343/0x18c0 net/ipv4/ipmr.c:2866
 netlink_dump+0x541/0xc20 net/netlink/af_netlink.c:2275
 __netlink_dump_start+0x647/0x900 net/netlink/af_netlink.c:2380
 netlink_dump_start include/linux/netlink.h:245 [inline]
 rtnetlink_rcv_msg+0x73e/0xc90 net/core/rtnetlink.c:6046
 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2501
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x543/0x7f0 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x917/0xe10 net/netlink/af_netlink.c:1921
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:734
 ____sys_sendmsg+0x334/0x810 net/socket.c:2489
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2543
 __sys_sendmmsg+0x195/0x470 net/socket.c:2629
 __do_sys_sendmmsg net/socket.c:2658 [inline]
 __se_sys_sendmmsg net/socket.c:2655 [inline]
 __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2655
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7f254f889109
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f254e9fe168 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f254f99bf60 RCX: 00007f254f889109
RDX: 0000000004924b68 RSI: 0000000020000140 RDI: 0000000000000003
RBP: 00007f254f8e305d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffff1b428df R14: 00007f254e9fe300 R15: 0000000000022000
 </TASK>

Crashes (11):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci-upstream-net-kasan-gce 2022/06/28 04:51 net-next c83bc86a0596 ef82eb2c .config console log report info WARNING: suspicious RCU usage in ipmr_rtm_dumplink
ci-upstream-net-kasan-gce 2022/06/28 02:59 net-next c83bc86a0596 ef82eb2c .config console log report info WARNING: suspicious RCU usage in ipmr_rtm_dumplink
ci-upstream-net-kasan-gce 2022/06/27 16:29 net-next c83bc86a0596 a371c43c .config console log report info WARNING: suspicious RCU usage in ipmr_rtm_dumplink
ci-upstream-net-kasan-gce 2022/06/27 11:39 net-next c83bc86a0596 a371c43c .config console log report info WARNING: suspicious RCU usage in ipmr_rtm_dumplink
ci-upstream-net-kasan-gce 2022/06/27 04:59 net-next ebeae54d3a77 a371c43c .config console log report info WARNING: suspicious RCU usage in ipmr_rtm_dumplink
ci-upstream-net-kasan-gce 2022/06/26 13:33 net-next ebeae54d3a77 a371c43c .config console log report info WARNING: suspicious RCU usage in ipmr_rtm_dumplink
ci-upstream-net-kasan-gce 2022/06/26 09:33 net-next ebeae54d3a77 a371c43c .config console log report info WARNING: suspicious RCU usage in ipmr_rtm_dumplink
ci-upstream-net-kasan-gce 2022/06/25 02:13 net-next 5d04b0b634bb a371c43c .config console log report info WARNING: suspicious RCU usage in ipmr_rtm_dumplink
ci-upstream-net-kasan-gce 2022/06/25 01:50 net-next 5d04b0b634bb a371c43c .config console log report info WARNING: suspicious RCU usage in ipmr_rtm_dumplink
ci-upstream-linux-next-kasan-gce-root 2022/06/27 17:37 linux-next aab35c3d5112 ef82eb2c .config console log report info WARNING: suspicious RCU usage in ipmr_rtm_dumplink
ci-upstream-linux-next-kasan-gce-root 2022/06/27 07:18 linux-next aab35c3d5112 a371c43c .config console log report info WARNING: suspicious RCU usage in ipmr_rtm_dumplink
* Struck through repros no longer work on HEAD.