linux-next boot error: WARNING: suspicious RCU usage in ip6mr_get_table

[syzbot <syzbot+761cff389b454aa387d2@syzkaller.appspotmail.com>]

Hello,

syzbot found the following crash on:

HEAD commit:    6b43f715 Add linux-next specific files for 20200507
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=16f64370100000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ef9b7a80b923f328
dashboard link: https://syzkaller.appspot.com/bug?extid=761cff389b454aa387d2
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+761cff389b454aa387d2@syzkaller.appspotmail.com

SoftiWARP attached
Driver 'framebuffer' was unable to register with bus_type 'coreboot' because the bus was not initialized.
Driver 'memconsole' was unable to register with bus_type 'coreboot' because the bus was not initialized.
Driver 'vpd' was unable to register with bus_type 'coreboot' because the bus was not initialized.
hid: raw HID events driver (C) Jiri Kosina
usbcore: registered new interface driver usbhid
usbhid: USB HID core driver
ashmem: initialized
usbcore: registered new interface driver snd-usb-audio
drop_monitor: Initializing network drop monitor service
NET: Registered protocol family 26
GACT probability on
Mirror/redirect action on
Simple TC action Loaded
netem: version 1.3
u32 classifier
    Performance counters on
    input device check on
    Actions configured
nf_conntrack_irc: failed to register helpers
nf_conntrack_sane: failed to register helpers
nf_conntrack_sip: failed to register helpers
xt_time: kernel timezone is -0000
IPVS: Registered protocols (TCP, UDP, SCTP, AH, ESP)
IPVS: Connection hash table configured (size=4096, memory=64Kbytes)
IPVS: ipvs loaded.
IPVS: [rr] scheduler registered.
IPVS: [wrr] scheduler registered.
IPVS: [lc] scheduler registered.
IPVS: [wlc] scheduler registered.
IPVS: [fo] scheduler registered.
IPVS: [ovf] scheduler registered.
IPVS: [lblc] scheduler registered.
IPVS: [lblcr] scheduler registered.
IPVS: [dh] scheduler registered.
IPVS: [sh] scheduler registered.
IPVS: [mh] scheduler registered.
IPVS: [sed] scheduler registered.
IPVS: [nq] scheduler registered.
IPVS: ftp: loaded support on port[0] = 21
IPVS: [sip] pe registered.
ipip: IPv4 and MPLS over IPv4 tunneling driver
gre: GRE over IPv4 demultiplexor driver
ip_gre: GRE over IPv4 tunneling driver
IPv4 over IPsec tunneling driver
ipt_CLUSTERIP: ClusterIP Version 0.8 loaded successfully
Initializing XFRM netlink socket
IPsec XFRM device driver
NET: Registered protocol family 10
=============================
WARNING: suspicious RCU usage
5.7.0-rc4-next-20200507-syzkaller #0 Not tainted
-----------------------------
net/ipv6/ip6mr.c:124 RCU-list traversed in non-reader section!!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
1 lock held by swapper/0/1:
 #0: ffffffff8a7aae30 (pernet_ops_rwsem){+.+.}-{3:3}, at: register_pernet_subsys+0x16/0x40 net/core/net_namespace.c:1257

stack backtrace:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc4-next-20200507-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+0x18f/0x20d lib/dump_stack.c:118
 ip6mr_get_table+0x153/0x180 net/ipv6/ip6mr.c:124
 ip6mr_new_table+0x1b/0x70 net/ipv6/ip6mr.c:382
 ip6mr_rules_init net/ipv6/ip6mr.c:236 [inline]
 ip6mr_net_init+0x133/0x3f0 net/ipv6/ip6mr.c:1310
 ops_init+0xaf/0x420 net/core/net_namespace.c:151
 __register_pernet_operations net/core/net_namespace.c:1140 [inline]
 register_pernet_operations+0x346/0x840 net/core/net_namespace.c:1217
 register_pernet_subsys+0x25/0x40 net/core/net_namespace.c:1258
 ip6_mr_init+0x49/0x152 net/ipv6/ip6mr.c:1363
 inet6_init+0x1d7/0x6dc net/ipv6/af_inet6.c:1037
 do_one_initcall+0x10a/0x7d0 init/main.c:1159
 do_initcall_level init/main.c:1232 [inline]
 do_initcalls init/main.c:1248 [inline]
 do_basic_setup init/main.c:1268 [inline]
 kernel_init_freeable+0x501/0x5ae init/main.c:1454
 kernel_init+0xd/0x1bb init/main.c:1359
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351
Segment Routing with IPv6
mip6: Mobile IPv6
sit: IPv6, IPv4 and MPLS over IPv4 tunneling driver
ip6_gre: GRE over IPv6 tunneling driver
NET: Registered protocol family 17
NET: Registered protocol family 15
Bridge firewalling registered
NET: Registered protocol family 9
X25: Linux Version 0.2
NET: Registered protocol family 6
NET: Registered protocol family 11
NET: Registered protocol family 3
can: controller area network core (rev 20170425 abi 9)
NET: Registered protocol family 29
can: raw protocol (rev 20170425)
can: broadcast manager protocol (rev 20170425 t)
can: netlink gateway (rev 20190810) max_hops=1
can: SAE J1939
Bluetooth: RFCOMM TTY layer initialized
Bluetooth: RFCOMM socket layer initialized
Bluetooth: RFCOMM ver 1.11
Bluetooth: BNEP (Ethernet Emulation) ver 1.3
Bluetooth: BNEP filters: protocol multicast
Bluetooth: BNEP socket layer initialized
Bluetooth: CMTP (CAPI Emulation) ver 1.0
Bluetooth: CMTP socket layer initialized
Bluetooth: HIDP (Human Interface Emulation) ver 1.2
Bluetooth: HIDP socket layer initialized
RPC: Registered rdma transport module.
RPC: Registered rdma backchannel transport module.
NET: Registered protocol family 33
Key type rxrpc registered
Key type rxrpc_s registered
NET: Registered protocol family 41
lec:lane_module_init: lec.c: initialized
mpoa:atm_mpoa_init: mpc.c: initialized
l2tp_core: L2TP core driver, V2.0
l2tp_ppp: PPPoL2TP kernel driver, V2.0
l2tp_ip: L2TP IP encapsulation support (L2TPv3)
l2tp_netlink: L2TP netlink interface
l2tp_eth: L2TP ethernet pseudowire support (L2TPv3)
l2tp_ip6: L2TP IP encapsulation support for IPv6 (L2TPv3)
NET: Registered protocol family 35
8021q: 802.1Q VLAN Support v1.8
DCCP: Activated CCID 2 (TCP-like)
DCCP: Activated CCID 3 (TCP-Friendly Rate Control)
sctp: Hash tables configured (bind 32/56)
NET: Registered protocol family 21
Registered RDS/infiniband transport
Registered RDS/tcp transport
tipc: Activated (version 2.0.0)
NET: Registered protocol family 30
tipc: Started in single node mode
NET: Registered protocol family 43
9pnet: Installing 9P2000 support
NET: Registered protocol family 37
NET: Registered protocol family 36
Key type dns_resolver registered
Key type ceph registered
libceph: loaded (mon/osd proto 15/24)
batman_adv: B.A.T.M.A.N. advanced 2020.2 (compatibility version 15) loaded
openvswitch: Open vSwitch switching datapath
NET: Registered protocol family 40
mpls_gso: MPLS GSO support
IPI shorthand broadcast: enabled
AVX2 version of gcm_enc/dec engaged.
AES CTR mode by8 optimization enabled
sched_clock: Marking stable (12995625706, 30506909)->(13027042353, -909738)
registered taskstats version 1
Loading compiled-in X.509 certificates
Loaded X.509 cert 'Build time autogenerated kernel key: 8b22f477d966bfa6cf9a482acbda6ca1892a4acc'
zswap: loaded using pool lzo/zbud
debug_vm_pgtable: debug_vm_pgtable: Validating architecture page table helpers
Key type ._fscrypt registered
Key type .fscrypt registered
Key type fscrypt-provisioning registered
kAFS: Red Hat AFS client v0.1 registering.
FS-Cache: Netfs 'afs' registered for caching
Btrfs loaded, crc32c=crc32c-intel
Key type big_key registered
Key type encrypted registered
AppArmor: AppArmor sha1 policy hashing enabled
ima: No TPM chip found, activating TPM-bypass!
ima: Allocated hash algorithm: sha256
ima: No architecture policies found
evm: Initialising EVM extended attributes:
evm: security.selinux
evm: security.SMACK64
evm: security.SMACK64EXEC
evm: security.SMACK64TRANSMUTE
evm: security.SMACK64MMAP
evm: security.apparmor
evm: security.ima
evm: security.capability
evm: HMAC attrs: 0x1
PM:   Magic number: 4:395:573
usbmon usbmon13: hash matches
tty ptyb5: hash matches
printk: console [netcon0] enabled
netconsole: network logging started
gtp: GTP module loaded (pdp ctx size 104 bytes)
rdma_rxe: loaded
cfg80211: Loading compiled-in X.509 certificates for regulatory database
cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
ALSA device list:
  #0: Dummy 1
  #1: Loopback 1
  #2: Virtual MIDI Card 1
md: Waiting for all devices to be available before autodetect
md: If you don't use raid, use raid=noautodetect
md: Autodetecting RAID arrays.
md: autorun ...
md: ... autorun DONE.
EXT4-fs (sda1): mounted filesystem without journal. Opts: (null)
VFS: Mounted root (ext4 filesystem) readonly on device 8:1.
devtmpfs: mounted
Freeing unused kernel image (initmem) memory: 2784K
Kernel memory protection disabled.
Run /sbin/init as init process
random: systemd: uninitialized urandom read (16 bytes read)
random: systemd: uninitialized urandom read (16 bytes read)
random: systemd: uninitialized urandom read (16 bytes read)
systemd[1]: systemd 232 running in system mode. (+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD +IDN)
systemd[1]: Detected virtualization kvm.
systemd[1]: Detected architecture x86-64.
systemd[1]: Set hostname to <syzkaller>.
systemd[1]: Listening on Journal Audit Socket.
systemd[1]: Listening on Journal Socket (/dev/log).
systemd[1]: Listening on Syslog Socket.
systemd[1]: Started Dispatch Password Requests to Console Directory Watch.
systemd[1]: Reached target Remote File Systems.

=============================
WARNING: suspicious RCU usage
5.7.0-rc4-next-20200507-syzkaller #0 Not tainted
-----------------------------
security/integrity/evm/evm_main.c:231 RCU-list traversed in non-reader section!!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
2 locks held by systemd/1:
 #0: ffff88809867e450 (sb_writers#8){.+.+}-{0:0}, at: sb_start_write include/linux/fs.h:1663 [inline]
 #0: ffff88809867e450 (sb_writers#8){.+.+}-{0:0}, at: mnt_want_write+0x3a/0xb0 fs/namespace.c:354
 #1: ffff8880989712d0 (&type->i_mutex_dir_key#6){++++}-{3:3}, at: inode_lock include/linux/fs.h:799 [inline]
 #1: ffff8880989712d0 (&type->i_mutex_dir_key#6){++++}-{3:3}, at: vfs_setxattr+0x92/0xf0 fs/xattr.c:219

stack backtrace:
CPU: 1 PID: 1 Comm: systemd Not tainted 5.7.0-rc4-next-20200507-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+0x18f/0x20d lib/dump_stack.c:118
 evm_protected_xattr+0x1c2/0x210 security/integrity/evm/evm_main.c:231
 evm_protect_xattr.isra.0+0xb6/0x3d0 security/integrity/evm/evm_main.c:318
 evm_inode_setxattr+0xc4/0xf0 security/integrity/evm/evm_main.c:387
 security_inode_setxattr+0x18f/0x200 security/security.c:1297
 vfs_setxattr+0xa7/0xf0 fs/xattr.c:220
 setxattr+0x23d/0x330 fs/xattr.c:451
 path_setxattr+0x170/0x190 fs/xattr.c:470
 __do_sys_setxattr fs/xattr.c:485 [inline]
 __se_sys_setxattr fs/xattr.c:481 [inline]
 __x64_sys_setxattr+0xc0/0x160 fs/xattr.c:481
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x7ff804be467a
Code: 48 8b 0d 21 18 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 bc 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ee 17 2b 00 f7 d8 64 89 01 48
RSP: 002b:00007ffd6a5afa98 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff804be467a
RDX: 00007ffd6a5afb10 RSI: 0000563851e78f9b RDI: 000056385393e6c0
RBP: 0000563851e78f9b R08: 0000000000000000 R09: 0000000000000030
R10: 0000000000000020 R11: 0000000000000246 R12: 00007ffd6a5afb10
R13: 0000000000000020 R14: 0000000000000000 R15: 00005638539151b0


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