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author | Chuck Lever <chuck.lever@oracle.com> | 2017-10-16 18:14:33 +0200 |
---|---|---|
committer | J. Bruce Fields <bfields@redhat.com> | 2017-11-07 22:44:00 +0100 |
commit | 0bad47cada5defba13e98827d22d06f13258dfb3 (patch) | |
tree | 84cd73d9913a5812d072e57a2ce4867098719533 /net | |
parent | nfds: avoid gettimeofday for nfssvc_boot time (diff) | |
download | linux-0bad47cada5defba13e98827d22d06f13258dfb3.tar.xz linux-0bad47cada5defba13e98827d22d06f13258dfb3.zip |
svcrdma: Preserve CB send buffer across retransmits
During each NFSv4 callback Call, an RDMA Send completion frees the
page that contains the RPC Call message. If the upper layer
determines that a retransmit is necessary, this is too soon.
One possible symptom: after a GARBAGE_ARGS response an NFSv4.1
callback request, the following BUG fires on the NFS server:
kernel: BUG: Bad page state in process kworker/0:2H pfn:7d3ce2
kernel: page:ffffea001f4f3880 count:-2 mapcount:0 mapping: (null) index:0x0
kernel: flags: 0x2fffff80000000()
kernel: raw: 002fffff80000000 0000000000000000 0000000000000000 fffffffeffffffff
kernel: raw: dead000000000100 dead000000000200 0000000000000000 0000000000000000
kernel: page dumped because: nonzero _refcount
kernel: Modules linked in: cts rpcsec_gss_krb5 ocfs2_dlmfs ocfs2_stack_o2cb ocfs2_dlm
ocfs2_nodemanager ocfs2_stackglue rpcrdm a ib_ipoib rdma_ucm ib_ucm ib_uverbs ib_umad
rdma_cm ib_cm iw_cm x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel
kvm irqbypass crct10dif_pc lmul crc32_pclmul ghash_clmulni_intel pcbc iTCO_wdt
iTCO_vendor_support aesni_intel crypto_simd glue_helper cryptd pcspkr lpc_ich i2c_i801
mei_me mf d_core mei raid0 sg wmi ioatdma ipmi_si ipmi_devintf ipmi_msghandler shpchp
acpi_power_meter acpi_pad nfsd nfs_acl lockd auth_rpcgss grace sunrpc ip_tables xfs
libcrc32c mlx4_en mlx4_ib mlx5_ib ib_core sd_mod sr_mod cdrom ast drm_kms_helper
syscopyarea sysfillrect sysimgblt fb_sys_fops ttm ahci crc32c_intel libahci drm
mlx5_core igb libata mlx4_core dca i2c_algo_bit i2c_core nvme
kernel: ptp nvme_core pps_core dm_mirror dm_region_hash dm_log dm_mod dax
kernel: CPU: 0 PID: 11495 Comm: kworker/0:2H Not tainted 4.14.0-rc3-00001-g577ce48 #811
kernel: Hardware name: Supermicro Super Server/X10SRL-F, BIOS 1.0c 09/09/2015
kernel: Workqueue: ib-comp-wq ib_cq_poll_work [ib_core]
kernel: Call Trace:
kernel: dump_stack+0x62/0x80
kernel: bad_page+0xfe/0x11a
kernel: free_pages_check_bad+0x76/0x78
kernel: free_pcppages_bulk+0x364/0x441
kernel: ? ttwu_do_activate.isra.61+0x71/0x78
kernel: free_hot_cold_page+0x1c5/0x202
kernel: __put_page+0x2c/0x36
kernel: svc_rdma_put_context+0xd9/0xe4 [rpcrdma]
kernel: svc_rdma_wc_send+0x50/0x98 [rpcrdma]
This issue exists all the way back to v4.5, but refactoring and code
re-organization prevents this simple patch from applying to kernels
older than v4.12. The fix is the same, however, if someone needs to
backport it.
Reported-by: Ben Coddington <bcodding@redhat.com>
BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=314
Fixes: 5d252f90a800 ('svcrdma: Add class for RDMA backwards ... ')
Cc: stable@vger.kernel.org # v4.12
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'net')
-rw-r--r-- | net/sunrpc/xprtrdma/svc_rdma_backchannel.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c index ec37ad83b068..1854db227742 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c +++ b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c @@ -132,6 +132,10 @@ static int svc_rdma_bc_sendto(struct svcxprt_rdma *rdma, if (ret) goto out_err; + /* Bump page refcnt so Send completion doesn't release + * the rq_buffer before all retransmits are complete. + */ + get_page(virt_to_page(rqst->rq_buffer)); ret = svc_rdma_post_send_wr(rdma, ctxt, 1, 0); if (ret) goto out_unmap; @@ -164,7 +168,6 @@ xprt_rdma_bc_allocate(struct rpc_task *task) return -EINVAL; } - /* svc_rdma_sendto releases this page */ page = alloc_page(RPCRDMA_DEF_GFP); if (!page) return -ENOMEM; @@ -183,6 +186,7 @@ xprt_rdma_bc_free(struct rpc_task *task) { struct rpc_rqst *rqst = task->tk_rqstp; + put_page(virt_to_page(rqst->rq_buffer)); kfree(rqst->rq_rbuffer); } |