5.4-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ Upstream commit 9b271ebaf9a2c5c566a54bc6cd915962e8241130 ]
syzbot/KCSAN reported data-races in iptunnel_xmit_stats() [1]
This can run from multiple cpus without mutual exclusion.
Adopt SMP safe DEV_STATS_INC() to update dev->stats fields.
[1] BUG: KCSAN: data-race in iptunnel_xmit / iptunnel_xmit
read-write to 0xffff8881353df170 of 8 bytes by task 30263 on cpu 1: iptunnel_xmit_stats include/net/ip_tunnels.h:493 [inline] iptunnel_xmit+0x432/0x4a0 net/ipv4/ip_tunnel_core.c:87 ip_tunnel_xmit+0x1477/0x1750 net/ipv4/ip_tunnel.c:831 __gre_xmit net/ipv4/ip_gre.c:469 [inline] ipgre_xmit+0x516/0x570 net/ipv4/ip_gre.c:662 __netdev_start_xmit include/linux/netdevice.h:4889 [inline] netdev_start_xmit include/linux/netdevice.h:4903 [inline] xmit_one net/core/dev.c:3544 [inline] dev_hard_start_xmit+0x11b/0x3f0 net/core/dev.c:3560 __dev_queue_xmit+0xeee/0x1de0 net/core/dev.c:4340 dev_queue_xmit include/linux/netdevice.h:3082 [inline] __bpf_tx_skb net/core/filter.c:2129 [inline] __bpf_redirect_no_mac net/core/filter.c:2159 [inline] __bpf_redirect+0x723/0x9c0 net/core/filter.c:2182 ____bpf_clone_redirect net/core/filter.c:2453 [inline] bpf_clone_redirect+0x16c/0x1d0 net/core/filter.c:2425 ___bpf_prog_run+0xd7d/0x41e0 kernel/bpf/core.c:1954 __bpf_prog_run512+0x74/0xa0 kernel/bpf/core.c:2195 bpf_dispatcher_nop_func include/linux/bpf.h:1181 [inline] __bpf_prog_run include/linux/filter.h:609 [inline] bpf_prog_run include/linux/filter.h:616 [inline] bpf_test_run+0x15d/0x3d0 net/bpf/test_run.c:423 bpf_prog_test_run_skb+0x77b/0xa00 net/bpf/test_run.c:1045 bpf_prog_test_run+0x265/0x3d0 kernel/bpf/syscall.c:3996 __sys_bpf+0x3af/0x780 kernel/bpf/syscall.c:5353 __do_sys_bpf kernel/bpf/syscall.c:5439 [inline] __se_sys_bpf kernel/bpf/syscall.c:5437 [inline] __x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5437 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd
read-write to 0xffff8881353df170 of 8 bytes by task 30249 on cpu 0: iptunnel_xmit_stats include/net/ip_tunnels.h:493 [inline] iptunnel_xmit+0x432/0x4a0 net/ipv4/ip_tunnel_core.c:87 ip_tunnel_xmit+0x1477/0x1750 net/ipv4/ip_tunnel.c:831 __gre_xmit net/ipv4/ip_gre.c:469 [inline] ipgre_xmit+0x516/0x570 net/ipv4/ip_gre.c:662 __netdev_start_xmit include/linux/netdevice.h:4889 [inline] netdev_start_xmit include/linux/netdevice.h:4903 [inline] xmit_one net/core/dev.c:3544 [inline] dev_hard_start_xmit+0x11b/0x3f0 net/core/dev.c:3560 __dev_queue_xmit+0xeee/0x1de0 net/core/dev.c:4340 dev_queue_xmit include/linux/netdevice.h:3082 [inline] __bpf_tx_skb net/core/filter.c:2129 [inline] __bpf_redirect_no_mac net/core/filter.c:2159 [inline] __bpf_redirect+0x723/0x9c0 net/core/filter.c:2182 ____bpf_clone_redirect net/core/filter.c:2453 [inline] bpf_clone_redirect+0x16c/0x1d0 net/core/filter.c:2425 ___bpf_prog_run+0xd7d/0x41e0 kernel/bpf/core.c:1954 __bpf_prog_run512+0x74/0xa0 kernel/bpf/core.c:2195 bpf_dispatcher_nop_func include/linux/bpf.h:1181 [inline] __bpf_prog_run include/linux/filter.h:609 [inline] bpf_prog_run include/linux/filter.h:616 [inline] bpf_test_run+0x15d/0x3d0 net/bpf/test_run.c:423 bpf_prog_test_run_skb+0x77b/0xa00 net/bpf/test_run.c:1045 bpf_prog_test_run+0x265/0x3d0 kernel/bpf/syscall.c:3996 __sys_bpf+0x3af/0x780 kernel/bpf/syscall.c:5353 __do_sys_bpf kernel/bpf/syscall.c:5439 [inline] __se_sys_bpf kernel/bpf/syscall.c:5437 [inline] __x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5437 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd
value changed: 0x0000000000018830 -> 0x0000000000018831
Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 30249 Comm: syz-executor.4 Not tainted 6.5.0-syzkaller-11704-g3f86ed6ec0b3 #0
Fixes: 039f50629b7f ("ip_tunnel: Move stats update to iptunnel_xmit()") Reported-by: syzbot syzkaller@googlegroups.com Signed-off-by: Eric Dumazet edumazet@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/ip_tunnels.h | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h index 8d063e23aa408..36376f8b84dac 100644 --- a/include/net/ip_tunnels.h +++ b/include/net/ip_tunnels.h @@ -449,15 +449,14 @@ static inline void iptunnel_xmit_stats(struct net_device *dev, int pkt_len) tstats->tx_packets++; u64_stats_update_end(&tstats->syncp); put_cpu_ptr(tstats); + return; + } + + if (pkt_len < 0) { + DEV_STATS_INC(dev, tx_errors); + DEV_STATS_INC(dev, tx_aborted_errors); } else { - struct net_device_stats *err_stats = &dev->stats; - - if (pkt_len < 0) { - err_stats->tx_errors++; - err_stats->tx_aborted_errors++; - } else { - err_stats->tx_dropped++; - } + DEV_STATS_INC(dev, tx_dropped); } }