linux-stable.git/include/linux/sunrpc, branch v6.12.97

SUNRPC: pin upper rpc_clnt across the TLS connect_worker

2026-07-24T14:11:24+00:00

[ Upstream commit 46bc86c833956219bbfd246c1ffd832a479c5199 ]

The TLS connect path has a use-after-free: nothing pins the
upper rpc_clnt across the delayed connect_worker. xs_connect()
stores task->tk_client in sock_xprt::clnt as a raw pointer
and queues the worker; for TLS-secured transports that worker
is xs_tcp_tls_setup_socket(), which reads several fields out
of the saved pointer (cl_timeout, cl_program, cl_prog,
cl_vers, cl_cred, cl_stats) to construct the args for the
inner handshake rpc_clnt.

The xprt does not reference the rpc_clnt; the rpc_clnt
references the xprt. xs_destroy() does cancel the
connect_worker, but it runs only when the xprt's refcount
drops to zero, which cannot happen until the rpc_clnt
releases its cl_xprt reference in rpc_free_client_work().
When a TLS handshake fails fatally (for example, an mTLS
mount whose client cert does not match the server), the
connecting task is woken with -EACCES and exits, the mount
caller invokes rpc_shutdown_client(), and the upper rpc_clnt
is freed before the queued connect_worker fires.
xs_tcp_tls_setup_socket() then dereferences the freed clnt,
producing the refcount_t underflow Michael Nemanov reported.

Take a reference on the upper rpc_clnt in xs_connect() for
TLS transports via a new rpc_hold_client() helper, and drop
it in the connect_worker's exit path with rpc_release_client().
The xprt_lock_connect() / xprt_unlock_connect() pairing
already serialises xs_connect() with xs_tcp_tls_setup_socket(),
so the take and release are balanced one-for-one.

The non-TLS connect worker (xs_tcp_setup_socket) never reads
sock_xprt::clnt, so leave that path alone and avoid the
clnt-holds-xprt-holds-clnt cycle that would otherwise prevent
xprt destruction.

Reported-by: Michael Nemanov 
Closes: https://lore.kernel.org/linux-nfs/40e3d522-dfcf-4fc1-9c55-b5e81f1536d5@vastdata.com/
Fixes: 75eb6af7acdf ("SUNRPC: Add a TCP-with-TLS RPC transport class")
Signed-off-by: Chuck Lever 
Tested-by: Michael Nemanov 
Reviewed-by: Michael Nemanov 
Signed-off-by: Anna Schumaker 
Signed-off-by: Sasha Levin

xprtrdma: Close lost-wakeup race in xprt_rdma_alloc_slot

2026-07-24T14:11:07+00:00

[ Upstream commit 765bde47fe7f197dabeb12da76831f40d0b20377 ]

xprt_rdma_alloc_slot() and xprt_rdma_free_slot() lack serialization
between the buffer pool and the backlog queue.  A buffer freed
after rpcrdma_buffer_get() finds the pool empty but before
rpc_sleep_on() places the task on the backlog is returned to the
pool with no waiter to wake, leaving the task stuck on the backlog
indefinitely.

After joining the backlog, re-check the pool and route any
recovered buffer through xprt_wake_up_backlog(), whose queue lock
serializes with concurrent wakeups and avoids double-assignment
of slots.

Because xprt_rdma_free_slot() does not hold reserve_lock, the
XPRT_CONGESTED double-check in xprt_throttle_congested() is
ineffective: a task can join the backlog through that path after
free_slot has already found it empty and cleared the bit.  Avoid
this by using xprt_add_backlog_noncongested(), which queues the
task without setting XPRT_CONGESTED, so every allocation reaches
xprt_rdma_alloc_slot() and its post-sleep re-check.

Fixes: edb41e61a54e ("xprtrdma: Make rpc_rqst part of rpcrdma_req")
Signed-off-by: Chuck Lever 
Signed-off-by: Trond Myklebust 
Stable-dep-of: e786233d2e0b ("xprtrdma: Decouple req recycling from RPC completion")
Signed-off-by: Sasha Levin

xdrgen: Initialize data pointer for zero-length items

2026-03-04T12:20:05+00:00

[ Upstream commit 27b0fcae8f535fb882b1876227a935dcfdf576aa ]

The xdrgen decoders for strings and opaque data had an
optimization that skipped calling xdr_inline_decode() when the
item length was zero. This left the data pointer uninitialized,
which could lead to unpredictable behavior when callers access
it.

Remove the zero-length check and always call xdr_inline_decode().
When passed a length of zero, xdr_inline_decode() returns the
current buffer position, which is valid and matches the behavior
of hand-coded XDR decoders throughout the kernel.

Fixes: 4b132aacb076 ("tools: Add xdrgen")
Reviewed-by: Jeff Layton 
Reviewed-by: NeilBrown 
Signed-off-by: Chuck Lever 
Signed-off-by: Sasha Levin

nfsd: unregister with rpcbind when deleting a transport

2025-10-19T14:34:03+00:00

[ Upstream commit 898374fdd7f06fa4c4a66e8be3135efeae6128d5 ]

When a listener is added, a part of creation of transport also registers
program/port with rpcbind. However, when the listener is removed,
while transport goes away, rpcbind still has the entry for that
port/type.

When deleting the transport, unregister with rpcbind when appropriate.

---v2 created a new xpt_flag XPT_RPCB_UNREG to mark TCP and UDP
transport and at xprt destroy send rpcbind unregister if flag set.

Suggested-by: Chuck Lever 
Fixes: d093c9089260 ("nfsd: fix management of listener transports")
Cc: stable@vger.kernel.org
Signed-off-by: Olga Kornievskaia 
Reviewed-by: Jeff Layton 
Signed-off-by: Chuck Lever 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

nfsd: don't use sv_nrthreads in connection limiting calculations.

2025-10-19T14:34:03+00:00

[ Upstream commit eccbbc7c00a5aae5e704d4002adfaf4c3fa4b30d ]

The heuristic for limiting the number of incoming connections to nfsd
currently uses sv_nrthreads - allowing more connections if more threads
were configured.

A future patch will allow number of threads to grow dynamically so that
there will be no need to configure sv_nrthreads.  So we need a different
solution for limiting connections.

It isn't clear what problem is solved by limiting connections (as
mentioned in a code comment) but the most likely problem is a connection
storm - many connections that are not doing productive work.  These will
be closed after about 6 minutes already but it might help to slow down a
storm.

This patch adds a per-connection flag XPT_PEER_VALID which indicates
that the peer has presented a filehandle for which it has some sort of
access.  i.e the peer is known to be trusted in some way.  We now only
count connections which have NOT been determined to be valid.  There
should be relative few of these at any given time.

If the number of non-validated peer exceed a limit - currently 64 - we
close the oldest non-validated peer to avoid having too many of these
useless connections.

Note that this patch significantly changes the meaning of the various
configuration parameters for "max connections".  The next patch will
remove all of these.

Signed-off-by: NeilBrown 
Reviewed-by: Jeff Layton 
Signed-off-by: Chuck Lever 
Stable-dep-of: 898374fdd7f0 ("nfsd: unregister with rpcbind when deleting a transport")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

SUNRPC: Prevent looping due to rpc_signal_task() races

2025-03-07T17:25:27+00:00

[ Upstream commit 5bbd6e863b15a85221e49b9bdb2d5d8f0bb91f3d ]

If rpc_signal_task() is called while a task is in an rpc_call_done()
callback function, and the latter calls rpc_restart_call(), the task can
end up looping due to the RPC_TASK_SIGNALLED flag being set without the
tk_rpc_status being set.
Removing the redundant mechanism for signalling the task fixes the
looping behaviour.

Reported-by: Li Lingfeng 
Fixes: 39494194f93b ("SUNRPC: Fix races with rpc_killall_tasks()")
Signed-off-by: Trond Myklebust 
Reviewed-by: Jeff Layton 
Signed-off-by: Anna Schumaker 
Signed-off-by: Sasha Levin

move asm/unaligned.h to linux/unaligned.h

2024-10-02T21:23:23+00:00

asm/unaligned.h is always an include of asm-generic/unaligned.h;
might as well move that thing to linux/unaligned.h and include
that - there's nothing arch-specific in that header.

auto-generated by the following:

for i in `git grep -l -w asm/unaligned.h`; do
	sed -i -e "s/asm\/unaligned.h/linux\/unaligned.h/" $i
done
for i in `git grep -l -w asm-generic/unaligned.h`; do
	sed -i -e "s/asm-generic\/unaligned.h/linux\/unaligned.h/" $i
done
git mv include/asm-generic/unaligned.h include/linux/unaligned.h
git mv tools/include/asm-generic/unaligned.h tools/include/linux/unaligned.h
sed -i -e "/unaligned.h/d" include/asm-generic/Kbuild
sed -i -e "s/__ASM_GENERIC/__LINUX/" include/linux/unaligned.h tools/include/linux/unaligned.h

SUNRPC: replace program list with program array

2024-09-23T19:03:30+00:00

A service created with svc_create_pooled() can be given a linked list of
programs and all of these will be served.

Using a linked list makes it cumbersome when there are several programs
that can be optionally selected with CONFIG settings.

After this patch is applied, API consumers must use only
svc_create_pooled() when creating an RPC service that listens for more
than one RPC program.

Signed-off-by: NeilBrown 
Signed-off-by: Mike Snitzer 
Acked-by: Chuck Lever 
Reviewed-by: Jeff Layton 
Signed-off-by: Anna Schumaker

SUNRPC: add svcauth_map_clnt_to_svc_cred_local

2024-09-23T19:03:30+00:00

Add new funtion svcauth_map_clnt_to_svc_cred_local which maps a
generic cred to a svc_cred suitable for use in nfsd.

This is needed by the localio code to map nfs client creds to nfs
server credentials.

Following from net/sunrpc/auth_unix.c:unx_marshal() it is clear that
->fsuid and ->fsgid must be used (rather than ->uid and ->gid).  In
addition, these uid and gid must be translated with from_kuid_munged()
so local client uses correct uid and gid when acting as local server.

Jeff Layton noted:
  This is where the magic happens. Since we're working in
  kuid_t/kgid_t, we don't need to worry about further idmapping.

Suggested-by: NeilBrown  # to approximate unx_marshal()
Signed-off-by: Weston Andros Adamson 
Signed-off-by: Trond Myklebust 
Co-developed-by: Mike Snitzer 
Signed-off-by: Mike Snitzer 
Reviewed-by: Chuck Lever 
Reviewed-by: Jeff Layton 
Reviewed-by: NeilBrown 
Signed-off-by: Anna Schumaker

SUNRPC: convert RPC_TASK_* constants to enum

2024-09-23T19:03:13+00:00

The RPC_TASK_* constants are defined as macros, which means that most
kernel builds will not contain their definitions in the debuginfo.
However, it's quite useful for debuggers to be able to view the task
state constant and interpret it correctly. Conversion to an enum will
ensure the constants are present in debuginfo and can be interpreted by
debuggers without needing to hard-code them and track their changes.

Signed-off-by: Stephen Brennan 
Signed-off-by: Anna Schumaker