Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Date:   Fri, 8 May 2020 04:54:02 +0530
To:     Qian Cai <cai@lca.pw>
Cc:     Amol Grover <frextrite@gmail.com>,
        Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>,
        syzbot <syzbot+761cff389b454aa387d2@syzkaller.appspotmail.com>,
        Linux-Next Mailing List <linux-next@vger.kernel.org>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        David Miller <davem@davemloft.net>, kuba@kernel.org,
        Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
        LKML <linux-kernel@vger.kernel.org>,
        netdev <netdev@vger.kernel.org>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        Dmitry Vyukov <dvyukov@google.com>
Subject: Re: linux-next boot error: WARNING: suspicious RCU usage in
 ip6mr_get_table
Message-ID: <20200507232402.GB2103@madhuparna-HP-Notebook>
References: <00000000000003dc8f05a50b798e@google.com>
 <CACT4Y+bzRtZdLSzHTp-kJZo4Qg7QctXNVEY9=kbAzfMck9XxAA@mail.gmail.com>
 <DB6FF2E0-4605-40D1-B368-7D813518F6F7@lca.pw>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <DB6FF2E0-4605-40D1-B368-7D813518F6F7@lca.pw>
User-Agent: Mutt/1.9.4 (2018-02-28)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, May 07, 2020 at 08:50:55AM -0400, Qian Cai wrote:
> 
> 
> > On May 7, 2020, at 5:32 AM, Dmitry Vyukov <dvyukov@google.com> wrote:
> > 
> > On Thu, May 7, 2020 at 11:26 AM syzbot
> > <syzbot+761cff389b454aa387d2@syzkaller.appspotmail.com> wrote:
> >> 
> >> 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
> > 
> > 
> > +linux-next for linux-next boot breakage
> 
> Amol, Madhuparna, Is either of you still working on this?
> 
> > 
> >> 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!!
> >>
I had some doubt in this one, I have already mailed the maintainers,
waiting for their reply.

> >> 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!!
> >> 
Here is the patch for this one:
https://lore.kernel.org/patchwork/patch/1233836/

Thank you,
Madhuparna

> >> 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
> >> 
> >> 
> >> ---
> >> This bug 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 syzkaller@googlegroups.com.
> >> 
> >> syzbot will keep track of this bug report. See:
> >> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> >> 
> >> --
> >> You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group.
> >> To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com.
> >> To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/00000000000003dc8f05a50b798e%40google.com.
>