Wei Wang 7f041ee8ef ipv6: fix suspecious RCU usage warning ... [ Upstream commit 28259bac7f1dde06d8ba324e222bbec9d4e92f2b ] Syzbot reported the suspecious RCU usage in nexthop_fib6_nh() when called from ipv6_route_seq_show(). The reason is ipv6_route_seq_start() calls rcu_read_lock_bh(), while nexthop_fib6_nh() calls rcu_dereference_rtnl(). The fix proposed is to add a variant of nexthop_fib6_nh() to use rcu_dereference_bh_rtnl() for ipv6_route_seq_show(). The reported trace is as follows: ./include/net/nexthop.h:416 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 2 locks held by syz-executor.0/17895: at: seq_read+0x71/0x12a0 fs/seq_file.c:169 at: seq_file_net include/linux/seq_file_net.h:19 [inline] at: ipv6_route_seq_start+0xaf/0x300 net/ipv6/ip6_fib.c:2616 stack backtrace: CPU: 1 PID: 17895 Comm: syz-executor.0 Not tainted 4.15.0-syzkaller #0 Call Trace: [<ffffffff849edf9e>] __dump_stack lib/dump_stack.c:17 [inline] [<ffffffff849edf9e>] dump_stack+0xd8/0x147 lib/dump_stack.c:53 [<ffffffff8480b7fa>] lockdep_rcu_suspicious+0x153/0x15d kernel/locking/lockdep.c:5745 [<ffffffff8459ada6>] nexthop_fib6_nh include/net/nexthop.h:416 [inline] [<ffffffff8459ada6>] ipv6_route_native_seq_show net/ipv6/ip6_fib.c:2488 [inline] [<ffffffff8459ada6>] ipv6_route_seq_show+0x436/0x7a0 net/ipv6/ip6_fib.c:2673 [<ffffffff81c556df>] seq_read+0xccf/0x12a0 fs/seq_file.c:276 [<ffffffff81dbc62c>] proc_reg_read+0x10c/0x1d0 fs/proc/inode.c:231 [<ffffffff81bc28ae>] do_loop_readv_writev fs/read_write.c:714 [inline] [<ffffffff81bc28ae>] do_loop_readv_writev fs/read_write.c:701 [inline] [<ffffffff81bc28ae>] do_iter_read+0x49e/0x660 fs/read_write.c:935 [<ffffffff81bc81ab>] vfs_readv+0xfb/0x170 fs/read_write.c:997 [<ffffffff81c88847>] kernel_readv fs/splice.c:361 [inline] [<ffffffff81c88847>] default_file_splice_read+0x487/0x9c0 fs/splice.c:416 [<ffffffff81c86189>] do_splice_to+0x129/0x190 fs/splice.c:879 [<ffffffff81c86f66>] splice_direct_to_actor+0x256/0x890 fs/splice.c:951 [<ffffffff81c8777d>] do_splice_direct+0x1dd/0x2b0 fs/splice.c:1060 [<ffffffff81bc4747>] do_sendfile+0x597/0xce0 fs/read_write.c:1459 [<ffffffff81bca205>] SYSC_sendfile64 fs/read_write.c:1520 [inline] [<ffffffff81bca205>] SyS_sendfile64+0x155/0x170 fs/read_write.c:1506 [<ffffffff81015fcf>] do_syscall_64+0x1ff/0x310 arch/x86/entry/common.c:305 [<ffffffff84a00076>] entry_SYSCALL_64_after_hwframe+0x42/0xb7 Fixes: f88d8ea67f ("ipv6: Plumb support for nexthop object in a fib6_info") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Wei Wang <weiwan@google.com> Cc: David Ahern <dsahern@kernel.org> Cc: Ido Schimmel <idosch@idosch.org> Cc: Petr Machata <petrm@nvidia.com> Cc: Eric Dumazet <edumazet@google.com> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>		2021-03-30 14:31:57 +02:00
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ila
netfilter
addrconf_core.c
addrconf.c
addrlabel.c
af_inet6.c
ah6.c
anycast.c
calipso.c	cipso,calipso: resolve a number of problems with the DOI refcounts	2021-03-17 17:06:15 +01:00
datagram.c
esp6_offload.c
esp6.c
exthdrs_core.c
exthdrs_offload.c
exthdrs.c
fib6_notifier.c
fib6_rules.c
fou6.c
icmp.c	net: icmp: pass zeroed opts from icmp{,v6}_ndo_send before sending	2021-03-04 11:38:46 +01:00
inet6_connection_sock.c
inet6_hashtables.c
ip6_checksum.c
ip6_fib.c	ipv6: fix suspecious RCU usage warning	2021-03-30 14:31:57 +02:00
ip6_flowlabel.c
ip6_gre.c	net: always use icmp{,v6}_ndo_send from ndo_start_xmit	2021-03-17 17:06:12 +01:00
ip6_icmp.c	net: icmp: pass zeroed opts from icmp{,v6}_ndo_send before sending	2021-03-04 11:38:46 +01:00
ip6_input.c
ip6_offload.c
ip6_offload.h
ip6_output.c
ip6_tunnel.c	net: always use icmp{,v6}_ndo_send from ndo_start_xmit	2021-03-17 17:06:12 +01:00
ip6_udp_tunnel.c
ip6_vti.c	net: always use icmp{,v6}_ndo_send from ndo_start_xmit	2021-03-17 17:06:12 +01:00
ip6mr.c
ipcomp6.c
ipv6_sockglue.c
Kconfig
Makefile
mcast_snoop.c
mcast.c
mip6.c
ndisc.c
netfilter.c
output_core.c
ping.c
proc.c
protocol.c
raw.c
reassembly.c
route.c
rpl_iptunnel.c
rpl.c
seg6_hmac.c
seg6_iptunnel.c
seg6_local.c
seg6.c
sit.c	net: always use icmp{,v6}_ndo_send from ndo_start_xmit	2021-03-17 17:06:12 +01:00
syncookies.c
sysctl_net_ipv6.c
tcp_ipv6.c
tcpv6_offload.c
tunnel6.c
udp_impl.h
udp_offload.c	udp: ipv4: manipulate network header of NATed UDP GRO fraglist	2021-02-10 09:29:23 +01:00
udp.c
udplite.c
xfrm6_input.c
xfrm6_output.c
xfrm6_policy.c
xfrm6_protocol.c
xfrm6_state.c
xfrm6_tunnel.c