Vadim Lomovtsev eebe53e87f net: sunrpc: svcsock: fix NULL-pointer exception ... While running nfs/connectathon tests kernel NULL-pointer exception has been observed due to races in svcsock.c. Race is appear when kernel accepts connection by kernel_accept (which creates new socket) and start queuing ingress packets to new socket. This happens in ksoftirq context which could run concurrently on a different core while new socket setup is not done yet. The fix is to re-order socket user data init sequence and add write/read barrier calls to be sure that we got proper values for callback pointers before actually calling them. Test results: nfs/connectathon reports '0' failed tests for about 200+ iterations. Crash log: ---<-snip->--- [ 6708.638984] Unable to handle kernel NULL pointer dereference at virtual address 00000000 [ 6708.647093] pgd = ffff0000094e0000 [ 6708.650497] [00000000] *pgd=0000010ffff90003, *pud=0000010ffff90003, *pmd=0000010ffff80003, *pte=0000000000000000 [ 6708.660761] Internal error: Oops: 86000005 [#1] SMP [ 6708.665630] Modules linked in: nfsv3 nfnetlink_queue nfnetlink_log nfnetlink rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache overlay xt_CONNSECMARK xt_SECMARK xt_conntrack iptable_security ip_tables ah4 xfrm4_mode_transport sctp tun binfmt_misc ext4 jbd2 mbcache loop tcp_diag udp_diag inet_diag rpcrdma ib_isert iscsi_target_mod ib_iser rdma_cm iw_cm libiscsi scsi_transport_iscsi ib_srpt target_core_mod ib_srp scsi_transport_srp ib_ipoib ib_ucm ib_uverbs ib_umad ib_cm ib_core nls_koi8_u nls_cp932 ts_kmp nf_conntrack_ipv4 nf_defrag_ipv4 nf_conntrack vfat fat ghash_ce sha2_ce sha1_ce cavium_rng_vf i2c_thunderx sg thunderx_edac i2c_smbus edac_core cavium_rng nfsd auth_rpcgss nfs_acl lockd grace sunrpc xfs libcrc32c nicvf nicpf ast i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops [ 6708.736446] ttm drm i2c_core thunder_bgx thunder_xcv mdio_thunder mdio_cavium dm_mirror dm_region_hash dm_log dm_mod [last unloaded: stap_3c300909c5b3f46dcacd49aab3334af_87021] [ 6708.752275] CPU: 84 PID: 0 Comm: swapper/84 Tainted: G W OE 4.11.0-4.el7.aarch64 #1 [ 6708.760787] Hardware name: www.cavium.com CRB-2S/CRB-2S, BIOS 0.3 Mar 13 2017 [ 6708.767910] task: ffff810006842e80 task.stack: ffff81000689c000 [ 6708.773822] PC is at 0x0 [ 6708.776739] LR is at svc_data_ready+0x38/0x88 [sunrpc] [ 6708.781866] pc : [<0000000000000000>] lr : [<ffff0000029d7378>] pstate: 60000145 [ 6708.789248] sp : ffff810ffbad3900 [ 6708.792551] x29: ffff810ffbad3900 x28: ffff000008c73d58 [ 6708.797853] x27: 0000000000000000 x26: ffff81000bbe1e00 [ 6708.803156] x25: 0000000000000020 x24: ffff800f7410bf28 [ 6708.808458] x23: ffff000008c63000 x22: ffff000008c63000 [ 6708.813760] x21: ffff800f7410bf28 x20: ffff81000bbe1e00 [ 6708.819063] x19: ffff810012412400 x18: 00000000d82a9df2 [ 6708.824365] x17: 0000000000000000 x16: 0000000000000000 [ 6708.829667] x15: 0000000000000000 x14: 0000000000000001 [ 6708.834969] x13: 0000000000000000 x12: 722e736f622e676e [ 6708.840271] x11: 00000000f814dd99 x10: 0000000000000000 [ 6708.845573] x9 : 7374687225000000 x8 : 0000000000000000 [ 6708.850875] x7 : 0000000000000000 x6 : 0000000000000000 [ 6708.856177] x5 : 0000000000000028 x4 : 0000000000000000 [ 6708.861479] x3 : 0000000000000000 x2 : 00000000e5000000 [ 6708.866781] x1 : 0000000000000000 x0 : ffff81000bbe1e00 [ 6708.872084] [ 6708.873565] Process swapper/84 (pid: 0, stack limit = 0xffff81000689c000) [ 6708.880341] Stack: (0xffff810ffbad3900 to 0xffff8100068a0000) [ 6708.886075] Call trace: [ 6708.888513] Exception stack(0xffff810ffbad3710 to 0xffff810ffbad3840) [ 6708.894942] 3700: ffff810012412400 0001000000000000 [ 6708.902759] 3720: ffff810ffbad3900 0000000000000000 0000000060000145 ffff800f79300000 [ 6708.910577] 3740: ffff000009274d00 00000000000003ea 0000000000000015 ffff000008c63000 [ 6708.918395] 3760: ffff810ffbad3830 ffff800f79300000 000000000000004d 0000000000000000 [ 6708.926212] 3780: ffff810ffbad3890 ffff0000080f88dc ffff800f79300000 000000000000004d [ 6708.934030] 37a0: ffff800f7930093c ffff000008c63000 0000000000000000 0000000000000140 [ 6708.941848] 37c0: ffff000008c2c000 0000000000040b00 ffff81000bbe1e00 0000000000000000 [ 6708.949665] 37e0: 00000000e5000000 0000000000000000 0000000000000000 0000000000000028 [ 6708.957483] 3800: 0000000000000000 0000000000000000 0000000000000000 7374687225000000 [ 6708.965300] 3820: 0000000000000000 00000000f814dd99 722e736f622e676e 0000000000000000 [ 6708.973117] [< (null)>] (null) [ 6708.977824] [<ffff0000086f9fa4>] tcp_data_queue+0x754/0xc5c [ 6708.983386] [<ffff0000086fa64c>] tcp_rcv_established+0x1a0/0x67c [ 6708.989384] [<ffff000008704120>] tcp_v4_do_rcv+0x15c/0x22c [ 6708.994858] [<ffff000008707418>] tcp_v4_rcv+0xaf0/0xb58 [ 6709.000077] [<ffff0000086df784>] ip_local_deliver_finish+0x10c/0x254 [ 6709.006419] [<ffff0000086dfea4>] ip_local_deliver+0xf0/0xfc [ 6709.011980] [<ffff0000086dfad4>] ip_rcv_finish+0x208/0x3a4 [ 6709.017454] [<ffff0000086e018c>] ip_rcv+0x2dc/0x3c8 [ 6709.022328] [<ffff000008692fc8>] __netif_receive_skb_core+0x2f8/0xa0c [ 6709.028758] [<ffff000008696068>] __netif_receive_skb+0x38/0x84 [ 6709.034580] [<ffff00000869611c>] netif_receive_skb_internal+0x68/0xdc [ 6709.041010] [<ffff000008696bc0>] napi_gro_receive+0xcc/0x1a8 [ 6709.046690] [<ffff0000014b0fc4>] nicvf_cq_intr_handler+0x59c/0x730 [nicvf] [ 6709.053559] [<ffff0000014b1380>] nicvf_poll+0x38/0xb8 [nicvf] [ 6709.059295] [<ffff000008697a6c>] net_rx_action+0x2f8/0x464 [ 6709.064771] [<ffff000008081824>] __do_softirq+0x11c/0x308 [ 6709.070164] [<ffff0000080d14e4>] irq_exit+0x12c/0x174 [ 6709.075206] [<ffff00000813101c>] __handle_domain_irq+0x78/0xc4 [ 6709.081027] [<ffff000008081608>] gic_handle_irq+0x94/0x190 [ 6709.086501] Exception stack(0xffff81000689fdf0 to 0xffff81000689ff20) [ 6709.092929] fde0: 0000810ff2ec0000 ffff000008c10000 [ 6709.100747] fe00: ffff000008c70ef4 0000000000000001 0000000000000000 ffff810ffbad9b18 [ 6709.108565] fe20: ffff810ffbad9c70 ffff8100169d3800 ffff810006843ab0 ffff81000689fe80 [ 6709.116382] fe40: 0000000000000bd0 0000ffffdf979cd0 183f5913da192500 0000ffff8a254ce4 [ 6709.124200] fe60: 0000ffff8a254b78 0000aaab10339808 0000000000000000 0000ffff8a0c2a50 [ 6709.132018] fe80: 0000ffffdf979b10 ffff000008d6d450 ffff000008c10000 ffff000008d6d000 [ 6709.139836] fea0: 0000000000000054 ffff000008cd3dbc 0000000000000000 0000000000000000 [ 6709.147653] fec0: 0000000000000000 0000000000000000 0000000000000000 ffff81000689ff20 [ 6709.155471] fee0: ffff000008085240 ffff81000689ff20 ffff000008085244 0000000060000145 [ 6709.163289] ff00: ffff81000689ff10 ffff00000813f1e4 ffffffffffffffff ffff00000813f238 [ 6709.171107] [<ffff000008082eb4>] el1_irq+0xb4/0x140 [ 6709.175976] [<ffff000008085244>] arch_cpu_idle+0x44/0x11c [ 6709.181368] [<ffff0000087bf3b8>] default_idle_call+0x20/0x30 [ 6709.187020] [<ffff000008116d50>] do_idle+0x158/0x1e4 [ 6709.191973] [<ffff000008116ff4>] cpu_startup_entry+0x2c/0x30 [ 6709.197624] [<ffff00000808e7cc>] secondary_start_kernel+0x13c/0x160 [ 6709.203878] [<0000000001bc71c4>] 0x1bc71c4 [ 6709.207967] Code: bad PC value [ 6709.211061] SMP: stopping secondary CPUs [ 6709.218830] Starting crashdump kernel... [ 6709.222749] Bye! ---<-snip>--- Signed-off-by: Vadim Lomovtsev <vlomovts@redhat.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields <bfields@redhat.com>		2017-08-24 18:11:28 -04:00
..
auth_gss	NFS client updates for Linux 4.13	2017-07-13 14:35:37 -07:00
xprtrdma	NFS client updates for Linux 4.13	2017-07-13 14:35:37 -07:00
addr.c
auth_generic.c	NFS client updates for Linux 4.9	2016-10-13 21:28:20 -07:00
auth_null.c	sunrpc: remove dead codes of cr_magic in rpc_cred	2017-02-08 17:02:46 -05:00
auth_unix.c	sunrpc: rename NFS_NGROUPS to UNX_NGROUPS for auth unix	2017-02-08 17:02:45 -05:00
auth.c	sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h>	2017-03-02 08:42:31 +01:00
backchannel_rqst.c	SUNRPC: Refactor rpc_xdr_buf_init()	2016-09-19 13:08:37 -04:00
cache.c	NFS client updates for Linux 4.11	2017-03-01 16:10:30 -08:00
clnt.c	sunrpc: mark all struct rpc_procinfo instances as const	2017-07-13 15:57:57 -04:00
debugfs.c	sunrpc: record rpc client pointer in seq->private directly	2017-02-08 17:02:47 -05:00
Kconfig	svcrdma: Introduce local rdma_rw API helpers	2017-04-25 17:25:55 -04:00
Makefile	SUNRPC: Add a structure to track multiple transports	2016-02-05 18:48:54 -05:00
netns.h	netns: make struct pernet_operations::id unsigned int	2016-11-18 10:59:15 -05:00
rpc_pipe.c	fs: Replace CURRENT_TIME with current_time() for inode timestamps	2016-09-27 21:06:21 -04:00
rpcb_clnt.c	sunrpc: mark all struct rpc_procinfo instances as const	2017-07-13 15:57:57 -04:00
sched.c	sunrpc: don't check for failure from mempool_alloc()	2017-04-20 13:44:57 -04:00
socklib.c	sunrpc: do not pull udp headers on receive	2016-04-11 15:31:33 -04:00
stats.c	sunrpc: move pc_count out of struct svc_procinfo	2017-07-13 15:58:02 -04:00
sunrpc_syms.c	SUNRPC: cleanup ida information when removing sunrpc module	2017-01-24 15:29:24 -05:00
sunrpc.h
svc_xprt.c	sunrpc: Allocate up to RPCSVC_MAXPAGES per svc_rqst	2017-07-12 15:54:55 -04:00
svc.c	sunrpc: mark all struct svc_version instances as const	2017-07-13 15:58:03 -04:00
svcauth_unix.c	sunrpc: rename NFS_NGROUPS to UNX_NGROUPS for auth unix	2017-02-08 17:02:45 -05:00
svcauth.c	locking/atomic, kref: Implement kref_put_lock()	2017-01-18 10:03:29 +01:00
svcsock.c	net: sunrpc: svcsock: fix NULL-pointer exception	2017-08-24 18:11:28 -04:00
sysctl.c	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
timer.c
xdr.c	sunrpc: Fix xdr_init_decode_pages() documenting comment	2017-04-25 16:12:34 -04:00
xprt.c	SUNRPC: Make slot allocation more reliable	2017-07-13 15:58:04 -04:00
xprtmultipath.c	SUNRPC search xprt switch for sockaddr	2016-09-19 13:08:36 -04:00
xprtsock.c	SUNRPC: ensure correct error is reported by xs_tcp_setup_socket()	2017-05-31 12:26:44 -04:00