linux-stable.git/include/linux/sunrpc, branch v6.6.148

SUNRPC: Return an error from xdr_buf_to_bvec() on overflow

2026-08-03T09:15:37+00:00

[ Upstream commit 18c1cc69886192e33536498289d26dba6894e3d5 ]

xdr_buf_to_bvec() returns a slot count even when the caller's bvec
budget is exhausted partway through the xdr_buf. Callers feed that
count into iov_iter_bvec() and continue as if the conversion had
succeeded, silently sending or writing fewer bytes than the data
length declares. For an NFS WRITE the server reports the truncated
transfer to the client as full success.

The overflow represents an internal invariant violation: a higher
layer reserved a bvec budget too small for the xdr_buf it then
asked the encoder to convert. That is a server-side fault, not a
media I/O failure and not a malformed client argument.

Change xdr_buf_to_bvec() to return a signed int and have the
overflow label return -ESERVERFAULT. Update the three callers to
detect the negative return and fail the request: nfsd_vfs_write()
folds the error into host_err, which nfserrno() translates to
nfserr_serverfault for the WRITE reply; svc_udp_sendto() and
svc_tcp_sendmsg() propagate the error out of the send path.

Reported-by: Chris Mason 
Fixes: 2eb2b9358181 ("SUNRPC: Convert svc_tcp_sendmsg to use bio_vecs directly")
Cc: stable@vger.kernel.org
Reviewed-by: Jeff Layton 
Signed-off-by: Chuck Lever 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

SUNRPC: Add helpers to convert xdr_buf byte ranges to scatterlists

2026-08-03T09:15:37+00:00

[ Upstream commit e9be933959b581effd426f93b86654f5fbf0c574 ]

The crypto/krb5 library accepts data in scatterlist form, but
the GSS-API layer presents RPC payloads as struct xdr_buf.
Bridge that gap with a pair of helper functions:

  xdr_buf_to_sg()        - populate a caller-supplied scatterlist
                           array from a byte range
  xdr_buf_to_sg_alloc()  - populate a caller-supplied inline
                           scatterlist, chaining to a heap-
                           allocated overflow for large payloads

The inline array (typically stack-allocated at eight entries)
covers the common case of small RPCs with no heap allocation
on the encrypt/decrypt path. Only buffers spanning many pages
incur a kmalloc for the chained extension.

The segment-walking logic follows the same head, page array,
tail traversal as xdr_process_buf(), but populates a
scatterlist directly rather than invoking a per-segment
callback. sg_next() traversal makes the walker safe for
chained scatterlists. Once subsequent patches reroute all
per-message crypto operations through crypto/krb5,
xdr_process_buf() loses its last callers and is removed.

Assisted-by: Claude:claude-opus-4-6
Reviewed-by: Jeff Layton 
Acked-by: Anna Schumaker 
Signed-off-by: Chuck Lever 
Stable-dep-of: 18c1cc698861 ("SUNRPC: Return an error from xdr_buf_to_bvec() on overflow")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

sunrpc: allocate a separate bvec array for socket sends

2026-08-03T09:15:37+00:00

[ Upstream commit 6b3b697d65d46a0f640216a3f6c72856c159c567 ]

svc_tcp_sendmsg() calls xdr_buf_to_bvec() with the second slot of
rq_bvec as the start, but doesn't reduce the array length by one, which
could lead to an array overrun. Also, rq_bvec is always rq_maxpages in
length, which can be too short in some cases, since the TCP record
marker consumes a slot.

Fix both problems by adding a separate bvec array to the svc_sock that
is specifically for sending. For TCP, make this array one slot longer
than rq_maxpages, to account for the record marker. For UDP, only
allocate as large an array as we need since it's limited to 64k of
payload.

Signed-off-by: Jeff Layton 
Reviewed-by: NeilBrown 
Signed-off-by: Chuck Lever 
Stable-dep-of: 18c1cc698861 ("SUNRPC: Return an error from xdr_buf_to_bvec() on overflow")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

SUNRPC: pin upper rpc_clnt across the TLS connect_worker

2026-07-24T14:03:29+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

2026-07-24T14:03:16+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

SUNRPC: Prevent looping due to rpc_signal_task() races

2025-03-07T15:45:36+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

SUNRPC: convert RPC_TASK_* constants to enum

2025-03-07T15:45:36+00:00

[ Upstream commit 0b108e83795c9c23101f584ef7e3ab4f1f120ef0 ]

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 
Stable-dep-of: 5bbd6e863b15 ("SUNRPC: Prevent looping due to rpc_signal_task() races")
Signed-off-by: Sasha Levin

sunrpc: remove ->pg_stats from svc_program

2024-08-19T04:04:23+00:00

[ Upstream commit 3f6ef182f144dcc9a4d942f97b6a8ed969f13c95 ]

Now that this isn't used anywhere, remove it.

Signed-off-by: Josef Bacik 
Reviewed-by: Jeff Layton 
Signed-off-by: Chuck Lever 
Signed-off-by: Greg Kroah-Hartman

sunrpc: pass in the sv_stats struct through svc_create_pooled

2024-08-19T04:04:23+00:00

[ Upstream commit f094323867668d50124886ad884b665de7319537 ]

Since only one service actually reports the rpc stats there's not much
of a reason to have a pointer to it in the svc_program struct.  Adjust
the svc_create_pooled function to take the sv_stats as an argument and
pass the struct through there as desired instead of getting it from the
svc_program->pg_stats.

Signed-off-by: Josef Bacik 
Reviewed-by: Jeff Layton 
[ cel: adjusted to apply to v6.6.y ]
Signed-off-by: Chuck Lever 
Signed-off-by: Greg Kroah-Hartman

sunrpc: add a struct rpc_stats arg to rpc_create_args

2024-05-17T10:01:57+00:00

[ Upstream commit 2057a48d0dd00c6a2a94ded7df2bf1d3f2a4a0da ]

We want to be able to have our rpc stats handled in a per network
namespace manner, so add an option to rpc_create_args to specify a
different rpc_stats struct instead of using the one on the rpc_program.

Signed-off-by: Josef Bacik 
Signed-off-by: Trond Myklebust 
Stable-dep-of: 24457f1be29f ("nfs: Handle error of rpc_proc_register() in nfs_net_init().")
Signed-off-by: Sasha Levin