Add patch to fix NFS backtrace (rhbz 1188638)

kernel.spec

@@ -612,6 +612,9 @@ Patch26129: samsung-laptop-Add-use_native_backlight-quirk-and-en.patch
 #rhbz 1094948
 Patch26131: acpi-video-Add-disable_native_backlight-quirk-for-Sa.patch
 
+#rhbz 1188638
+Patch26132: nfs-don-t-call-blocking-operations-while-TASK_RUNNIN.patch
+
 # git clone ssh://git.fedorahosted.org/git/kernel-arm64.git, git diff master...devel
 Patch30000: kernel-arm64.patch
 
@@ -1340,6 +1343,9 @@ ApplyPatch samsung-laptop-Add-use_native_backlight-quirk-and-en.patch
 #rhbz 1094948
 ApplyPatch acpi-video-Add-disable_native_backlight-quirk-for-Sa.patch
 
+#rhbz 1188638
+ApplyPatch nfs-don-t-call-blocking-operations-while-TASK_RUNNIN.patch
+
 %if 0%{?aarch64patches}
 ApplyPatch kernel-arm64.patch
 %ifnarch aarch64 # this is stupid, but i want to notice before secondary koji does.
@@ -2206,6 +2212,9 @@ fi
 #                                    ||----w |
 #                                    ||     ||
 %changelog
+* Tue Feb 03 2015 Josh Boyer <jwboyer@fedoraproject.org>
+- Add patch to fix NFS backtrace (rhbz 1188638)
+
 * Mon Feb 02 2015 Josh Boyer <jwboyer@fedoraproject.org> - 3.19.0-0.rc7.git0.1
 - Linux v3.19-rc7
 - Disable debugging options.

nfs-don-t-call-blocking-operations-while-TASK_RUNNIN.patch

@@ -0,0 +1,91 @@
+From: Jeff Layton <jlayton@primarydata.com>
+Date: Wed, 14 Jan 2015 13:08:57 -0500
+Subject: [PATCH] nfs: don't call blocking operations while !TASK_RUNNING
+
+Bruce reported seeing this warning pop when mounting using v4.1:
+
+     ------------[ cut here ]------------
+     WARNING: CPU: 1 PID: 1121 at kernel/sched/core.c:7300 __might_sleep+0xbd/0xd0()
+    do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff810ff58f>] prepare_to_wait+0x2f/0x90
+    Modules linked in: rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace sunrpc fscache ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw snd_hda_codec_generic snd_hda_intel snd_hda_controller snd_hda_codec snd_hwdep snd_pcm snd_timer ppdev joydev snd virtio_console virtio_balloon pcspkr serio_raw parport_pc parport pvpanic floppy soundcore i2c_piix4 virtio_blk virtio_net qxl drm_kms_helper ttm drm virtio_pci virtio_ring ata_generic virtio pata_acpi
+    CPU: 1 PID: 1121 Comm: nfsv4.1-svc Not tainted 3.19.0-rc4+ #25
+    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140709_153950- 04/01/2014
+     0000000000000000 000000004e5e3f73 ffff8800b998fb48 ffffffff8186ac78
+     0000000000000000 ffff8800b998fba0 ffff8800b998fb88 ffffffff810ac9da
+     ffff8800b998fb68 ffffffff81c923e7 00000000000004d9 0000000000000000
+    Call Trace:
+     [<ffffffff8186ac78>] dump_stack+0x4c/0x65
+     [<ffffffff810ac9da>] warn_slowpath_common+0x8a/0xc0
+     [<ffffffff810aca65>] warn_slowpath_fmt+0x55/0x70
+     [<ffffffff810ff58f>] ? prepare_to_wait+0x2f/0x90
+     [<ffffffff810ff58f>] ? prepare_to_wait+0x2f/0x90
+     [<ffffffff810dd2ad>] __might_sleep+0xbd/0xd0
+     [<ffffffff8124c973>] kmem_cache_alloc_trace+0x243/0x430
+     [<ffffffff810d941e>] ? groups_alloc+0x3e/0x130
+     [<ffffffff810d941e>] groups_alloc+0x3e/0x130
+     [<ffffffffa0301b1e>] svcauth_unix_accept+0x16e/0x290 [sunrpc]
+     [<ffffffffa0300571>] svc_authenticate+0xe1/0xf0 [sunrpc]
+     [<ffffffffa02fc564>] svc_process_common+0x244/0x6a0 [sunrpc]
+     [<ffffffffa02fd044>] bc_svc_process+0x1c4/0x260 [sunrpc]
+     [<ffffffffa03d5478>] nfs41_callback_svc+0x128/0x1f0 [nfsv4]
+     [<ffffffff810ff970>] ? wait_woken+0xc0/0xc0
+     [<ffffffffa03d5350>] ? nfs4_callback_svc+0x60/0x60 [nfsv4]
+     [<ffffffff810d45bf>] kthread+0x11f/0x140
+     [<ffffffff810ea815>] ? local_clock+0x15/0x30
+     [<ffffffff810d44a0>] ? kthread_create_on_node+0x250/0x250
+     [<ffffffff81874bfc>] ret_from_fork+0x7c/0xb0
+     [<ffffffff810d44a0>] ? kthread_create_on_node+0x250/0x250
+    ---[ end trace 675220a11e30f4f2 ]---
+
+nfs41_callback_svc does most of its work while in TASK_INTERRUPTIBLE,
+which is just wrong. Fix that by finishing the wait immediately if we've
+found that the list has something on it.
+
+Also, we don't expect this kthread to accept signals, so we should be
+using a TASK_UNINTERRUPTIBLE sleep instead. That however, opens us up
+hung task warnings from the watchdog, so have the schedule_timeout
+wake up every 60s if there's no callback activity.
+
+Reported-by: "J. Bruce Fields" <bfields@fieldses.org>
+Signed-off-by: Jeff Layton <jlayton@primarydata.com>
+Cc: stable@vger.kernel.org
+Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
+---
+ fs/nfs/callback.c | 8 +++++---
+ 1 file changed, 5 insertions(+), 3 deletions(-)
+
+diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
+index b8fb3a4ef649..351be9205bf8 100644
+--- a/fs/nfs/callback.c
++++ b/fs/nfs/callback.c
+@@ -128,22 +128,24 @@ nfs41_callback_svc(void *vrqstp)
+ 		if (try_to_freeze())
+ 			continue;
+ 
+-		prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
++		prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_UNINTERRUPTIBLE);
+ 		spin_lock_bh(&serv->sv_cb_lock);
+ 		if (!list_empty(&serv->sv_cb_list)) {
+ 			req = list_first_entry(&serv->sv_cb_list,
+ 					struct rpc_rqst, rq_bc_list);
+ 			list_del(&req->rq_bc_list);
+ 			spin_unlock_bh(&serv->sv_cb_lock);
++			finish_wait(&serv->sv_cb_waitq, &wq);
+ 			dprintk("Invoking bc_svc_process()\n");
+ 			error = bc_svc_process(serv, req, rqstp);
+ 			dprintk("bc_svc_process() returned w/ error code= %d\n",
+ 				error);
+ 		} else {
+ 			spin_unlock_bh(&serv->sv_cb_lock);
+-			schedule();
++			/* schedule_timeout to game the hung task watchdog */
++			schedule_timeout(60 * HZ);
++			finish_wait(&serv->sv_cb_waitq, &wq);
+ 		}
+-		finish_wait(&serv->sv_cb_waitq, &wq);
+ 	}
+ 	return 0;
+ }
+-- 
+2.1.0
+