Re: [PATCH] sunrpc: svc_age_temp_xprts_now should skip non-tcp transports

["J. Bruce Fields" <bfields@fieldses.org>]

On Mon, Nov 07, 2016 at 05:08:24PM -0500, Scott Mayhew wrote:
> On Mon, 07 Nov 2016, Chuck Lever wrote:
> 
> > 
> > > On Nov 7, 2016, at 1:47 PM, Scott Mayhew <smayhew@redhat.com> wrote:
> > > 
> > > This fixes the following panic that can occur with NFSoRDMA.
> > > 
> > > general protection fault: 0000 [#1] SMP
> > > Modules linked in: rpcrdma ib_isert iscsi_target_mod ib_iser libiscsi
> > > scsi_transport_iscsi ib_srpt target_core_mod ib_srp scsi_transport_srp
> > > scsi_tgt ib_ipoib rdma_ucm ib_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm
> > > mlx5_ib ib_core intel_powerclamp coretemp kvm_intel kvm sg ioatdma
> > > ipmi_devintf ipmi_ssif dcdbas iTCO_wdt iTCO_vendor_support pcspkr
> > > irqbypass sb_edac shpchp dca crc32_pclmul ghash_clmulni_intel edac_core
> > > lpc_ich aesni_intel lrw gf128mul glue_helper ablk_helper mei_me mei
> > > ipmi_si cryptd wmi ipmi_msghandler acpi_pad acpi_power_meter nfsd
> > > auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c sd_mod
> > > crc_t10dif crct10dif_generic mgag200 i2c_algo_bit drm_kms_helper
> > > syscopyarea sysfillrect sysimgblt ahci fb_sys_fops ttm libahci mlx5_core
> > > tg3 crct10dif_pclmul drm crct10dif_common
> > > ptp i2c_core libata crc32c_intel pps_core fjes dm_mirror dm_region_hash
> > > dm_log dm_mod
> > > CPU: 1 PID: 120 Comm: kworker/1:1 Not tainted 3.10.0-514.el7.x86_64 #1
> > > Hardware name: Dell Inc. PowerEdge R320/0KM5PX, BIOS 2.4.2 01/29/2015
> > > Workqueue: events check_lifetime
> > > task: ffff88031f506dd0 ti: ffff88031f584000 task.ti: ffff88031f584000
> > > RIP: 0010:[<ffffffff8168d847>]  [<ffffffff8168d847>]
> > > _raw_spin_lock_bh+0x17/0x50
> > > RSP: 0018:ffff88031f587ba8  EFLAGS: 00010206
> > > RAX: 0000000000020000 RBX: 20041fac02080072 RCX: ffff88031f587fd8
> > > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 20041fac02080072
> > > RBP: ffff88031f587bb0 R08: 0000000000000008 R09: ffffffff8155be77
> > > R10: ffff880322a59b00 R11: ffffea000bf39f00 R12: 20041fac02080072
> > > R13: 000000000000000d R14: ffff8800c4fbd800 R15: 0000000000000001
> > > FS:  0000000000000000(0000) GS:ffff880322a40000(0000)
> > > knlGS:0000000000000000
> > > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > CR2: 00007f3c52d4547e CR3: 00000000019ba000 CR4: 00000000001407e0
> > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > > DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> > > Stack:
> > > 20041fac02080002 ffff88031f587bd0 ffffffff81557830 20041fac02080002
> > > ffff88031f587c78 ffff88031f587c40 ffffffff8155ae08 000000010157df32
> > > 0000000800000001 ffff88031f587c20 ffffffff81096acb ffffffff81aa37d0
> > > Call Trace:
> > > [<ffffffff81557830>] lock_sock_nested+0x20/0x50
> > > [<ffffffff8155ae08>] sock_setsockopt+0x78/0x940
> > > [<ffffffff81096acb>] ? lock_timer_base.isra.33+0x2b/0x50
> > > [<ffffffff8155397d>] kernel_setsockopt+0x4d/0x50
> > > [<ffffffffa0386284>] svc_age_temp_xprts_now+0x174/0x1e0 [sunrpc]
> > > [<ffffffffa03b681d>] nfsd_inetaddr_event+0x9d/0xd0 [nfsd]
> > > [<ffffffff81691ebc>] notifier_call_chain+0x4c/0x70
> > > [<ffffffff810b687d>] __blocking_notifier_call_chain+0x4d/0x70
> > > [<ffffffff810b68b6>] blocking_notifier_call_chain+0x16/0x20
> > > [<ffffffff815e8538>] __inet_del_ifa+0x168/0x2d0
> > > [<ffffffff815e8cef>] check_lifetime+0x25f/0x270
> > > [<ffffffff810a7f3b>] process_one_work+0x17b/0x470
> > > [<ffffffff810a8d76>] worker_thread+0x126/0x410
> > > [<ffffffff810a8c50>] ? rescuer_thread+0x460/0x460
> > > [<ffffffff810b052f>] kthread+0xcf/0xe0
> > > [<ffffffff810b0460>] ? kthread_create_on_node+0x140/0x140
> > > [<ffffffff81696418>] ret_from_fork+0x58/0x90
> > > [<ffffffff810b0460>] ? kthread_create_on_node+0x140/0x140
> > > Code: ca 75 f1 5d c3 0f 1f 80 00 00 00 00 eb d9 66 0f 1f 44 00 00 0f 1f
> > > 44 00 00 55 48 89 e5 53 48 89 fb e8 7e 04 a0 ff b8 00 00 02 00 <f0> 0f
> > > c1 03 89 c2 c1 ea 10 66 39 c2 75 03 5b 5d c3 83 e2 fe 0f
> > > RIP  [<ffffffff8168d847>] _raw_spin_lock_bh+0x17/0x50
> > > RSP <ffff88031f587ba8>
> > > 
> > > Signed-off-by: Scott Mayhew <smayhew@redhat.com>
> > > Fixes: c3d4879e ("sunrpc: Add a function to close temporary transports immediately")
> > > ---
> > > include/linux/sunrpc/svc_xprt.h |  1 +
> > > net/sunrpc/svc_xprt.c           | 14 +++-----------
> > > net/sunrpc/svcsock.c            | 17 +++++++++++++++++
> > > 3 files changed, 21 insertions(+), 11 deletions(-)
> > > 
> > > diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h
> > > index ab02a45..4dbe0c9 100644
> > > --- a/include/linux/sunrpc/svc_xprt.h
> > > +++ b/include/linux/sunrpc/svc_xprt.h
> > > @@ -25,6 +25,7 @@ struct svc_xprt_ops {
> > > 	void		(*xpo_detach)(struct svc_xprt *);
> > > 	void		(*xpo_free)(struct svc_xprt *);
> > > 	int		(*xpo_secure_port)(struct svc_rqst *);
> > > +	void		(*xpo_notifier_cb)(struct svc_xprt *);
> > 
> > I'd prefer a less generic name for this callout: xpo_idle_close maybe?
> 
> I'm open to calling it something else, but it's not for the idle timer
> though.  This is for when the NFS server has one of its IP addresses
> yanked out from under it... for instance when
> rgmanager/pacemaker/serviceguard/whatever does an 'ip addr del' as part
> of the failover of an HA NFS service.

I'm normally a more peaceful person, but maybe xpo_kill_temp_xprts, or
xpo_kill_temps would succintly suggest "force these closed right away"?

--b.

> 
> > 
> > 
> > > };
> > > 
> > > struct svc_xprt_class {
> > > diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
> > > index c3f6523..b3c26af 100644
> > > --- a/net/sunrpc/svc_xprt.c
> > > +++ b/net/sunrpc/svc_xprt.c
> > > @@ -1002,18 +1002,14 @@ static void svc_age_temp_xprts(unsigned long closure)
> > > void svc_age_temp_xprts_now(struct svc_serv *serv, struct sockaddr *server_addr)
> > > {
> > > 	struct svc_xprt *xprt;
> > > -	struct svc_sock *svsk;
> > > -	struct socket *sock;
> > > 	struct list_head *le, *next;
> > > 	LIST_HEAD(to_be_closed);
> > > -	struct linger no_linger = {
> > > -		.l_onoff = 1,
> > > -		.l_linger = 0,
> > > -	};
> > > 
> > > 	spin_lock_bh(&serv->sv_lock);
> > > 	list_for_each_safe(le, next, &serv->sv_tempsocks) {
> > > 		xprt = list_entry(le, struct svc_xprt, xpt_list);
> > > +		if (!xprt->xpt_ops->xpo_notifier_cb)
> > > +			continue;
> > > 		if (rpc_cmp_addr(server_addr, (struct sockaddr *)
> > > 				&xprt->xpt_local)) {
> > > 			dprintk("svc_age_temp_xprts_now: found %p\n", xprt);
> > > @@ -1027,11 +1023,7 @@ void svc_age_temp_xprts_now(struct svc_serv *serv, struct sockaddr *server_addr)
> > > 		list_del_init(le);
> > > 		xprt = list_entry(le, struct svc_xprt, xpt_list);
> > > 		dprintk("svc_age_temp_xprts_now: closing %p\n", xprt);
> > > -		svsk = container_of(xprt, struct svc_sock, sk_xprt);
> > > -		sock = svsk->sk_sock;
> > > -		kernel_setsockopt(sock, SOL_SOCKET, SO_LINGER,
> > > -				  (char *)&no_linger, sizeof(no_linger));
> > > -		svc_close_xprt(xprt);
> > > +		xprt->xpt_ops->xpo_notifier_cb(xprt);
> > 
> > Shouldn't RDMA transports be aged out too?
> 
> The original patch was aimed at fixing a TCP-specific problem
> (http://nfsv4bat.org/Documents/ConnectAThon/1996/nfstcp.pdf page 16).
> I honestly didn't know if RDMA was susceptible to similar issues or not,
> so I decided just to skip non-TCP transports altogether.  My main
> concern is to make sure we don't pass something that's not a socket to
> kernel_setsockopt(), which is what was causing the panic with the original
> patch.  
> 
> -Scott
> 
> > 
> > 
> > > 	}
> > > }
> > > EXPORT_SYMBOL_GPL(svc_age_temp_xprts_now);
> > > diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
> > > index 57625f6..a65712c 100644
> > > --- a/net/sunrpc/svcsock.c
> > > +++ b/net/sunrpc/svcsock.c
> > > @@ -438,6 +438,22 @@ static int svc_tcp_has_wspace(struct svc_xprt *xprt)
> > > 	return !test_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
> > > }
> > > 
> > > +static void svc_tcp_notifier_cb(struct svc_xprt *xprt)
> > > +{
> > > +	struct svc_sock *svsk;
> > > +	struct socket *sock;
> > > +	struct linger no_linger = {
> > > +		.l_onoff = 1,
> > > +		.l_linger = 0,
> > > +	};
> > > +
> > > +	svsk = container_of(xprt, struct svc_sock, sk_xprt);
> > > +	sock = svsk->sk_sock;
> > > +	kernel_setsockopt(sock, SOL_SOCKET, SO_LINGER,
> > > +			  (char *)&no_linger, sizeof(no_linger));
> > > +	svc_close_xprt(xprt);
> > > +}
> > > +
> > > /*
> > >  * See net/ipv6/ip_sockglue.c : ip_cmsg_recv_pktinfo
> > >  */
> > > @@ -1242,6 +1258,7 @@ static struct svc_xprt_ops svc_tcp_ops = {
> > > 	.xpo_has_wspace = svc_tcp_has_wspace,
> > > 	.xpo_accept = svc_tcp_accept,
> > > 	.xpo_secure_port = svc_sock_secure_port,
> > > +	.xpo_notifier_cb = svc_tcp_notifier_cb,
> > > };
> > > 
> > > static struct svc_xprt_class svc_tcp_class = {
> > > -- 
> > > 2.4.11
> > > 
> > > --
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> > 
> > --
> > Chuck Lever
> > 
> > 
> >