linux-stable.git/net/sunrpc, branch v5.4.166

SUNRPC: Partial revert of commit 6f9f17287e78

2021-11-17T08:48:50+00:00

commit ea7a1019d8baf8503ecd6e3ec8436dec283569e6 upstream.

The premise of commit 6f9f17287e78 ("SUNRPC: Mitigate cond_resched() in
xprt_transmit()") was that cond_resched() is expensive and unnecessary
when there has been just a single send.
The point of cond_resched() is to ensure that tasks that should pre-empt
this one get a chance to do so when it is safe to do so. The code prior
to commit 6f9f17287e78 failed to take into account that it was keeping a
rpc_task pinned for longer than it needed to, and so rather than doing a
full revert, let's just move the cond_resched.

Signed-off-by: Trond Myklebust 
Signed-off-by: Greg Kroah-Hartman

rpc: fix gss_svc_init cleanup on failure

2021-09-22T10:26:33+00:00

[ Upstream commit 5a4753446253a427c0ff1e433b9c4933e5af207c ]

The failure case here should be rare, but it's obviously wrong.

Signed-off-by: J. Bruce Fields 
Signed-off-by: Chuck Lever 
Signed-off-by: Sasha Levin

SUNRPC: Fix potential memory corruption

2021-09-22T10:26:24+00:00

[ Upstream commit c2dc3e5fad13aca5d7bdf4bcb52b1a1d707c8555 ]

We really should not call rpc_wake_up_queued_task_set_status() with
xprt->snd_task as an argument unless we are certain that is actually an
rpc_task.

Fixes: 0445f92c5d53 ("SUNRPC: Fix disconnection races")
Signed-off-by: Trond Myklebust 
Signed-off-by: Anna Schumaker 
Signed-off-by: Sasha Levin

SUNRPC: Should wake up the privileged task firstly.

2021-07-14T14:53:05+00:00

commit 5483b904bf336948826594610af4c9bbb0d9e3aa upstream.

When find a task from wait queue to wake up, a non-privileged task may
be found out, rather than the privileged. This maybe lead a deadlock
same as commit dfe1fe75e00e ("NFSv4: Fix deadlock between nfs4_evict_inode()
and nfs4_opendata_get_inode()"):

Privileged delegreturn task is queued to privileged list because all
the slots are assigned. If there has no enough slot to wake up the
non-privileged batch tasks(session less than 8 slot), then the privileged
delegreturn task maybe lost waked up because the found out task can't
get slot since the session is on draining.

So we should treate the privileged task as the emergency task, and
execute it as for as we can.

Reported-by: Hulk Robot 
Fixes: 5fcdfacc01f3 ("NFSv4: Return delegations synchronously in evict_inode")
Cc: stable@vger.kernel.org
Signed-off-by: Zhang Xiaoxu 
Signed-off-by: Trond Myklebust 
Signed-off-by: Greg Kroah-Hartman

SUNRPC: Fix the batch tasks count wraparound.

2021-07-14T14:53:05+00:00

commit fcb170a9d825d7db4a3fb870b0300f5a40a8d096 upstream.

The 'queue->nr' will wraparound from 0 to 255 when only current
priority queue has tasks. This maybe lead a deadlock same as commit
dfe1fe75e00e ("NFSv4: Fix deadlock between nfs4_evict_inode()
and nfs4_opendata_get_inode()"):

Privileged delegreturn task is queued to privileged list because all
the slots are assigned. When non-privileged task complete and release
the slot, a non-privileged maybe picked out. It maybe allocate slot
failed when the session on draining.

If the 'queue->nr' has wraparound to 255, and no enough slot to
service it, then the privileged delegreturn will lost to wake up.

So we should avoid the wraparound on 'queue->nr'.

Reported-by: Hulk Robot 
Fixes: 5fcdfacc01f3 ("NFSv4: Return delegations synchronously in evict_inode")
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Zhang Xiaoxu 
Signed-off-by: Trond Myklebust 
Signed-off-by: Greg Kroah-Hartman

sunrpc: Fix misplaced barrier in call_decode

2021-05-19T08:08:27+00:00

[ Upstream commit f8f7e0fb22b2e75be55f2f0c13e229e75b0eac07 ]

Fix a misplaced barrier in call_decode. The struct rpc_rqst is modified
as follows by xprt_complete_rqst:

req->rq_private_buf.len = copied;
/* Ensure all writes are done before we update */
/* req->rq_reply_bytes_recvd */
smp_wmb();
req->rq_reply_bytes_recvd = copied;

And currently read as follows by call_decode:

smp_rmb(); // misplaced
if (!req->rq_reply_bytes_recvd)
   goto out;
req->rq_rcv_buf.len = req->rq_private_buf.len;

This patch places the smp_rmb after the if to ensure that
rq_reply_bytes_recvd and rq_private_buf.len are read in order.

Fixes: 9ba828861c56a ("SUNRPC: Don't try to parse incomplete RPC messages")
Signed-off-by: Baptiste Lepers 
Signed-off-by: Trond Myklebust 
Signed-off-by: Sasha Levin

rpc: fix NULL dereference on kmalloc failure

2021-04-07T12:47:38+00:00

[ Upstream commit 0ddc942394013f08992fc379ca04cffacbbe3dae ]

I think this is unlikely but possible:

svc_authenticate sets rq_authop and calls svcauth_gss_accept.  The
kmalloc(sizeof(*svcdata), GFP_KERNEL) fails, leaving rq_auth_data NULL,
and returning SVC_DENIED.

This causes svc_process_common to go to err_bad_auth, and eventually
call svc_authorise.  That calls ->release == svcauth_gss_release, which
tries to dereference rq_auth_data.

Signed-off-by: J. Bruce Fields 
Link: https://lore.kernel.org/linux-nfs/3F1B347F-B809-478F-A1E9-0BE98E22B0F0@oracle.com/T/#t
Signed-off-by: Chuck Lever 
Signed-off-by: Sasha Levin

sunrpc: fix refcount leak for rpc auth modules

2021-03-24T10:26:39+00:00

commit f1442d6349a2e7bb7a6134791bdc26cb776c79af upstream.

If an auth module's accept op returns SVC_CLOSE, svc_process_common()
enters a call path that does not call svc_authorise() before leaving the
function, and thus leaks a reference on the auth module's refcount. Hence,
make sure calls to svc_authenticate() and svc_authorise() are paired for
all call paths, to make sure rpc auth modules can be unloaded.

Signed-off-by: Daniel Kobras 
Fixes: 4d712ef1db05 ("svcauth_gss: Close connection when dropping an incoming message")
Link: https://lore.kernel.org/linux-nfs/3F1B347F-B809-478F-A1E9-0BE98E22B0F0@oracle.com/T/#t
Signed-off-by: Chuck Lever 
Signed-off-by: Greg Kroah-Hartman

svcrdma: disable timeouts on rdma backchannel

2021-03-24T10:26:38+00:00

commit 6820bf77864d5894ff67b5c00d7dba8f92011e3d upstream.

This brings it in line with the regular tcp backchannel, which also has
all those timeouts disabled.

Prevents the backchannel from timing out, getting some async operations
like server side copying getting stuck indefinitely on the client side.

Signed-off-by: Timo Rothenpieler 
Fixes: 5d252f90a800 ("svcrdma: Add class for RDMA backwards direction transport")
Signed-off-by: Chuck Lever 
Signed-off-by: Greg Kroah-Hartman

NFSD: Repair misuse of sv_lock in 5.10.16-rt30.

2021-03-24T10:26:38+00:00

commit c7de87ff9dac5f396f62d584f3908f80ddc0e07b upstream.

[ This problem is in mainline, but only rt has the chops to be
able to detect it. ]

Lockdep reports a circular lock dependency between serv->sv_lock and
softirq_ctl.lock on system shutdown, when using a kernel built with
CONFIG_PREEMPT_RT=y, and a nfs mount exists.

This is due to the definition of spin_lock_bh on rt:

	local_bh_disable();
	rt_spin_lock(lock);

which forces a softirq_ctl.lock -> serv->sv_lock dependency.  This is
not a problem as long as _every_ lock of serv->sv_lock is a:

	spin_lock_bh(&serv->sv_lock);

but there is one of the form:

	spin_lock(&serv->sv_lock);

This is what is causing the circular dependency splat.  The spin_lock()
grabs the lock without first grabbing softirq_ctl.lock via local_bh_disable.
If later on in the critical region,  someone does a local_bh_disable, we
get a serv->sv_lock -> softirq_ctrl.lock dependency established.  Deadlock.

Fix is to make serv->sv_lock be locked with spin_lock_bh everywhere, no
exceptions.

[  OK  ] Stopped target NFS client services.
         Stopping Logout off all iSCSI sessions on shutdown...
         Stopping NFS server and services...
[  109.442380]
[  109.442385] ======================================================
[  109.442386] WARNING: possible circular locking dependency detected
[  109.442387] 5.10.16-rt30 #1 Not tainted
[  109.442389] ------------------------------------------------------
[  109.442390] nfsd/1032 is trying to acquire lock:
[  109.442392] ffff994237617f60 ((softirq_ctrl.lock).lock){+.+.}-{2:2}, at: __local_bh_disable_ip+0xd9/0x270
[  109.442405]
[  109.442405] but task is already holding lock:
[  109.442406] ffff994245cb00b0 (&serv->sv_lock){+.+.}-{0:0}, at: svc_close_list+0x1f/0x90
[  109.442415]
[  109.442415] which lock already depends on the new lock.
[  109.442415]
[  109.442416]
[  109.442416] the existing dependency chain (in reverse order) is:
[  109.442417]
[  109.442417] -> #1 (&serv->sv_lock){+.+.}-{0:0}:
[  109.442421]        rt_spin_lock+0x2b/0xc0
[  109.442428]        svc_add_new_perm_xprt+0x42/0xa0
[  109.442430]        svc_addsock+0x135/0x220
[  109.442434]        write_ports+0x4b3/0x620
[  109.442438]        nfsctl_transaction_write+0x45/0x80
[  109.442440]        vfs_write+0xff/0x420
[  109.442444]        ksys_write+0x4f/0xc0
[  109.442446]        do_syscall_64+0x33/0x40
[  109.442450]        entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  109.442454]
[  109.442454] -> #0 ((softirq_ctrl.lock).lock){+.+.}-{2:2}:
[  109.442457]        __lock_acquire+0x1264/0x20b0
[  109.442463]        lock_acquire+0xc2/0x400
[  109.442466]        rt_spin_lock+0x2b/0xc0
[  109.442469]        __local_bh_disable_ip+0xd9/0x270
[  109.442471]        svc_xprt_do_enqueue+0xc0/0x4d0
[  109.442474]        svc_close_list+0x60/0x90
[  109.442476]        svc_close_net+0x49/0x1a0
[  109.442478]        svc_shutdown_net+0x12/0x40
[  109.442480]        nfsd_destroy+0xc5/0x180
[  109.442482]        nfsd+0x1bc/0x270
[  109.442483]        kthread+0x194/0x1b0
[  109.442487]        ret_from_fork+0x22/0x30
[  109.442492]
[  109.442492] other info that might help us debug this:
[  109.442492]
[  109.442493]  Possible unsafe locking scenario:
[  109.442493]
[  109.442493]        CPU0                    CPU1
[  109.442494]        ----                    ----
[  109.442495]   lock(&serv->sv_lock);
[  109.442496]                                lock((softirq_ctrl.lock).lock);
[  109.442498]                                lock(&serv->sv_lock);
[  109.442499]   lock((softirq_ctrl.lock).lock);
[  109.442501]
[  109.442501]  *** DEADLOCK ***
[  109.442501]
[  109.442501] 3 locks held by nfsd/1032:
[  109.442503]  #0: ffffffff93b49258 (nfsd_mutex){+.+.}-{3:3}, at: nfsd+0x19a/0x270
[  109.442508]  #1: ffff994245cb00b0 (&serv->sv_lock){+.+.}-{0:0}, at: svc_close_list+0x1f/0x90
[  109.442512]  #2: ffffffff93a81b20 (rcu_read_lock){....}-{1:2}, at: rt_spin_lock+0x5/0xc0
[  109.442518]
[  109.442518] stack backtrace:
[  109.442519] CPU: 0 PID: 1032 Comm: nfsd Not tainted 5.10.16-rt30 #1
[  109.442522] Hardware name: Supermicro X9DRL-3F/iF/X9DRL-3F/iF, BIOS 3.2 09/22/2015
[  109.442524] Call Trace:
[  109.442527]  dump_stack+0x77/0x97
[  109.442533]  check_noncircular+0xdc/0xf0
[  109.442546]  __lock_acquire+0x1264/0x20b0
[  109.442553]  lock_acquire+0xc2/0x400
[  109.442564]  rt_spin_lock+0x2b/0xc0
[  109.442570]  __local_bh_disable_ip+0xd9/0x270
[  109.442573]  svc_xprt_do_enqueue+0xc0/0x4d0
[  109.442577]  svc_close_list+0x60/0x90
[  109.442581]  svc_close_net+0x49/0x1a0
[  109.442585]  svc_shutdown_net+0x12/0x40
[  109.442588]  nfsd_destroy+0xc5/0x180
[  109.442590]  nfsd+0x1bc/0x270
[  109.442595]  kthread+0x194/0x1b0
[  109.442600]  ret_from_fork+0x22/0x30
[  109.518225] nfsd: last server has exited, flushing export cache
[  OK  ] Stopped NFSv4 ID-name mapping service.
[  OK  ] Stopped GSSAPI Proxy Daemon.
[  OK  ] Stopped NFS Mount Daemon.
[  OK  ] Stopped NFS status monitor for NFSv2/3 locking..

Fixes: 719f8bcc883e ("svcrpc: fix xpt_list traversal locking on shutdown")
Signed-off-by: Joe Korty 
Signed-off-by: Chuck Lever 
Signed-off-by: Greg Kroah-Hartman