This is a note to let you know that I've just added the patch titled net: sched: fix panic in rate estimators
to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-sched-fix-panic-in-rate-estimators.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@vger.kernel.org> know about it. >From foo@baz Thu Feb 12 09:25:54 HKT 2015 From: Eric Dumazet <eduma...@google.com> Date: Thu, 29 Jan 2015 17:30:12 -0800 Subject: net: sched: fix panic in rate estimators From: Eric Dumazet <eduma...@google.com> [ Upstream commit 0d32ef8cef9aa8f375e128f78b77caceaa7e8da0 ] Doing the following commands on a non idle network device panics the box instantly, because cpu_bstats gets overwritten by stats. tc qdisc add dev eth0 root <your_favorite_qdisc> ... some traffic (one packet is enough) ... tc qdisc replace dev eth0 root est 1sec 4sec <your_favorite_qdisc> [ 325.355596] BUG: unable to handle kernel paging request at ffff8841dc5a074c [ 325.362609] IP: [<ffffffff81541c9e>] __gnet_stats_copy_basic+0x3e/0x90 [ 325.369158] PGD 1fa7067 PUD 0 [ 325.372254] Oops: 0000 [#1] SMP [ 325.375514] Modules linked in: ... [ 325.398346] CPU: 13 PID: 14313 Comm: tc Not tainted 3.19.0-smp-DEV #1163 [ 325.412042] task: ffff8800793ab5d0 ti: ffff881ff2fa4000 task.ti: ffff881ff2fa4000 [ 325.419518] RIP: 0010:[<ffffffff81541c9e>] [<ffffffff81541c9e>] __gnet_stats_copy_basic+0x3e/0x90 [ 325.428506] RSP: 0018:ffff881ff2fa7928 EFLAGS: 00010286 [ 325.433824] RAX: 000000000000000c RBX: ffff881ff2fa796c RCX: 000000000000000c [ 325.440988] RDX: ffff8841dc5a0744 RSI: 0000000000000060 RDI: 0000000000000060 [ 325.448120] RBP: ffff881ff2fa7948 R08: ffffffff81cd4f80 R09: 0000000000000000 [ 325.455268] R10: ffff883ff223e400 R11: 0000000000000000 R12: 000000015cba0744 [ 325.462405] R13: ffffffff81cd4f80 R14: ffff883ff223e460 R15: ffff883feea0722c [ 325.469536] FS: 00007f2ee30fa700(0000) GS:ffff88407fa20000(0000) knlGS:0000000000000000 [ 325.477630] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 325.483380] CR2: ffff8841dc5a074c CR3: 0000003feeae9000 CR4: 00000000001407e0 [ 325.490510] Stack: [ 325.492524] ffff883feea0722c ffff883fef719dc0 ffff883feea0722c ffff883ff223e4a0 [ 325.499990] ffff881ff2fa79a8 ffffffff815424ee ffff883ff223e49c 000000015cba0744 [ 325.507460] 00000000f2fa7978 0000000000000000 ffff881ff2fa79a8 ffff883ff223e4a0 [ 325.514956] Call Trace: [ 325.517412] [<ffffffff815424ee>] gen_new_estimator+0x8e/0x230 [ 325.523250] [<ffffffff815427aa>] gen_replace_estimator+0x4a/0x60 [ 325.529349] [<ffffffff815718ab>] tc_modify_qdisc+0x52b/0x590 [ 325.535117] [<ffffffff8155edd0>] rtnetlink_rcv_msg+0xa0/0x240 [ 325.540963] [<ffffffff8155ed30>] ? __rtnl_unlock+0x20/0x20 [ 325.546532] [<ffffffff8157f811>] netlink_rcv_skb+0xb1/0xc0 [ 325.552145] [<ffffffff8155b355>] rtnetlink_rcv+0x25/0x40 [ 325.557558] [<ffffffff8157f0d8>] netlink_unicast+0x168/0x220 [ 325.563317] [<ffffffff8157f47c>] netlink_sendmsg+0x2ec/0x3e0 Lets play safe and not use an union : percpu 'pointers' are mostly read anyway, and we have typically few qdiscs per host. Signed-off-by: Eric Dumazet <eduma...@google.com> Cc: John Fastabend <john.fastab...@gmail.com> Fixes: 22e0f8b9322c ("net: sched: make bstats per cpu and estimator RCU safe") Signed-off-by: David S. Miller <da...@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- include/net/sch_generic.h | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -79,6 +79,9 @@ struct Qdisc { struct netdev_queue *dev_queue; struct gnet_stats_rate_est64 rate_est; + struct gnet_stats_basic_cpu __percpu *cpu_bstats; + struct gnet_stats_queue __percpu *cpu_qstats; + struct Qdisc *next_sched; struct sk_buff *gso_skb; /* @@ -86,15 +89,9 @@ struct Qdisc { */ unsigned long state; struct sk_buff_head q; - union { - struct gnet_stats_basic_packed bstats; - struct gnet_stats_basic_cpu __percpu *cpu_bstats; - } __packed; + struct gnet_stats_basic_packed bstats; unsigned int __state; - union { - struct gnet_stats_queue qstats; - struct gnet_stats_queue __percpu *cpu_qstats; - } __packed; + struct gnet_stats_queue qstats; struct rcu_head rcu_head; int padded; atomic_t refcnt; Patches currently in stable-queue which might be from eduma...@google.com are queue-3.18/tcp-ipv4-initialize-unicast_sock-sk_pacing_rate.patch queue-3.18/net-sched-fix-panic-in-rate-estimators.patch queue-3.18/ip-zero-sockaddr-returned-on-error-queue.patch queue-3.18/ping-fix-race-in-free-in-receive-path.patch queue-3.18/net-rps-fix-cpu-unplug.patch queue-3.18/netxen-fix-netxen_nic_poll-logic.patch queue-3.18/ipv4-tcp-get-rid-of-ugly-unicast_sock.patch queue-3.18/bnx2x-fix-napi-poll-return-value-for-repoll.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html