linux-stable.git/include/linux/sunrpc, branch v6.1.129

nfsd: Simplify code around svc_exit_thread() call in nfsd()

2024-08-29T15:30:52+00:00

[ Upstream commit 18e4cf915543257eae2925671934937163f5639b ]

Previously a thread could exit asynchronously (due to a signal) so some
care was needed to hold nfsd_mutex over the last svc_put() call.  Now a
thread can only exit when svc_set_num_threads() is called, and this is
always called under nfsd_mutex.  So no care is needed.

Not only is the mutex held when a thread exits now, but the svc refcount
is elevated, so the svc_put() in svc_exit_thread() will never be a final
put, so the mutex isn't even needed at this point in the code.

Signed-off-by: NeilBrown 
Signed-off-by: Chuck Lever 
Signed-off-by: Greg Kroah-Hartman

sunrpc: remove ->pg_stats from svc_program

2024-08-19T04:00:05+00:00

[ Upstream commit 3f6ef182f144dcc9a4d942f97b6a8ed969f13c95 ]

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

Signed-off-by: Josef Bacik 
Reviewed-by: Jeff Layton 
[ cel: adjusted to apply to v6.1.y ]
Signed-off-by: Chuck Lever 
Signed-off-by: Greg Kroah-Hartman

sunrpc: pass in the sv_stats struct through svc_create_pooled

2024-08-19T04:00:04+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 v6.1.y ]
Signed-off-by: Chuck Lever 
Signed-off-by: Greg Kroah-Hartman

sunrpc: add a struct rpc_stats arg to rpc_create_args

2024-05-17T09:55:54+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

SUNRPC: increase size of rpc_wait_queue.qlen from unsigned short to unsigned int

2024-04-13T11:05:11+00:00

[ Upstream commit 2c35f43b5a4b9cdfaa6fdd946f5a212615dac8eb ]

When the NFS client is under extreme load the rpc_wait_queue.qlen counter
can be overflowed. Here is an instant of the backlog queue overflow in a
real world environment shown by drgn helper:

rpc_task_stats(rpc_clnt):
-------------------------
rpc_clnt: 0xffff92b65d2bae00
rpc_xprt: 0xffff9275db64f000
  Queue:  sending[64887] pending[524] backlog[30441] binding[0]
XMIT task: 0xffff925c6b1d8e98
     WRITE: 750654
        __dta_call_status_580: 65463
        __dta_call_transmit_status_579: 1
        call_reserveresult: 685189
        nfs_client_init_is_complete: 1
    COMMIT: 584
        call_reserveresult: 573
        __dta_call_status_580: 11
    ACCESS: 1
        __dta_call_status_580: 1
   GETATTR: 10
        __dta_call_status_580: 4
        call_reserveresult: 6
751249 tasks for server 111.222.333.444
Total tasks: 751249

count_rpc_wait_queues(xprt):
----------------------------
**** rpc_xprt: 0xffff9275db64f000 num_reqs: 65511
wait_queue: xprt_binding[0] cnt: 0
wait_queue: xprt_binding[1] cnt: 0
wait_queue: xprt_binding[2] cnt: 0
wait_queue: xprt_binding[3] cnt: 0
rpc_wait_queue[xprt_binding].qlen: 0 maxpriority: 0
wait_queue: xprt_sending[0] cnt: 0
wait_queue: xprt_sending[1] cnt: 64887
wait_queue: xprt_sending[2] cnt: 0
wait_queue: xprt_sending[3] cnt: 0
rpc_wait_queue[xprt_sending].qlen: 64887 maxpriority: 3
wait_queue: xprt_pending[0] cnt: 524
wait_queue: xprt_pending[1] cnt: 0
wait_queue: xprt_pending[2] cnt: 0
wait_queue: xprt_pending[3] cnt: 0
rpc_wait_queue[xprt_pending].qlen: 524 maxpriority: 0
wait_queue: xprt_backlog[0] cnt: 0
wait_queue: xprt_backlog[1] cnt: 685801
wait_queue: xprt_backlog[2] cnt: 0
wait_queue: xprt_backlog[3] cnt: 0
rpc_wait_queue[xprt_backlog].qlen: 30441 maxpriority: 3 [task cnt mismatch]

There is no effect on operations when this overflow occurs. However
it causes confusion when trying to diagnose the performance problem.

Signed-off-by: Dai Ngo 
Reviewed-by: Jeff Layton 
Signed-off-by: Trond Myklebust 
Signed-off-by: Sasha Levin

SUNRPC: Fix RPC client cleaned up the freed pipefs dentries

2023-11-28T17:07:04+00:00

[ Upstream commit bfca5fb4e97c46503ddfc582335917b0cc228264 ]

RPC client pipefs dentries cleanup is in separated rpc_remove_pipedir()
workqueue,which takes care about pipefs superblock locking.
In some special scenarios, when kernel frees the pipefs sb of the
current client and immediately alloctes a new pipefs sb,
rpc_remove_pipedir function would misjudge the existence of pipefs
sb which is not the one it used to hold. As a result,
the rpc_remove_pipedir would clean the released freed pipefs dentries.

To fix this issue, rpc_remove_pipedir should check whether the
current pipefs sb is consistent with the original pipefs sb.

This error can be catched by KASAN:
=========================================================
[  250.497700] BUG: KASAN: slab-use-after-free in dget_parent+0x195/0x200
[  250.498315] Read of size 4 at addr ffff88800a2ab804 by task kworker/0:18/106503
[  250.500549] Workqueue: events rpc_free_client_work
[  250.501001] Call Trace:
[  250.502880]  kasan_report+0xb6/0xf0
[  250.503209]  ? dget_parent+0x195/0x200
[  250.503561]  dget_parent+0x195/0x200
[  250.503897]  ? __pfx_rpc_clntdir_depopulate+0x10/0x10
[  250.504384]  rpc_rmdir_depopulate+0x1b/0x90
[  250.504781]  rpc_remove_client_dir+0xf5/0x150
[  250.505195]  rpc_free_client_work+0xe4/0x230
[  250.505598]  process_one_work+0x8ee/0x13b0
...
[   22.039056] Allocated by task 244:
[   22.039390]  kasan_save_stack+0x22/0x50
[   22.039758]  kasan_set_track+0x25/0x30
[   22.040109]  __kasan_slab_alloc+0x59/0x70
[   22.040487]  kmem_cache_alloc_lru+0xf0/0x240
[   22.040889]  __d_alloc+0x31/0x8e0
[   22.041207]  d_alloc+0x44/0x1f0
[   22.041514]  __rpc_lookup_create_exclusive+0x11c/0x140
[   22.041987]  rpc_mkdir_populate.constprop.0+0x5f/0x110
[   22.042459]  rpc_create_client_dir+0x34/0x150
[   22.042874]  rpc_setup_pipedir_sb+0x102/0x1c0
[   22.043284]  rpc_client_register+0x136/0x4e0
[   22.043689]  rpc_new_client+0x911/0x1020
[   22.044057]  rpc_create_xprt+0xcb/0x370
[   22.044417]  rpc_create+0x36b/0x6c0
...
[   22.049524] Freed by task 0:
[   22.049803]  kasan_save_stack+0x22/0x50
[   22.050165]  kasan_set_track+0x25/0x30
[   22.050520]  kasan_save_free_info+0x2b/0x50
[   22.050921]  __kasan_slab_free+0x10e/0x1a0
[   22.051306]  kmem_cache_free+0xa5/0x390
[   22.051667]  rcu_core+0x62c/0x1930
[   22.051995]  __do_softirq+0x165/0x52a
[   22.052347]
[   22.052503] Last potentially related work creation:
[   22.052952]  kasan_save_stack+0x22/0x50
[   22.053313]  __kasan_record_aux_stack+0x8e/0xa0
[   22.053739]  __call_rcu_common.constprop.0+0x6b/0x8b0
[   22.054209]  dentry_free+0xb2/0x140
[   22.054540]  __dentry_kill+0x3be/0x540
[   22.054900]  shrink_dentry_list+0x199/0x510
[   22.055293]  shrink_dcache_parent+0x190/0x240
[   22.055703]  do_one_tree+0x11/0x40
[   22.056028]  shrink_dcache_for_umount+0x61/0x140
[   22.056461]  generic_shutdown_super+0x70/0x590
[   22.056879]  kill_anon_super+0x3a/0x60
[   22.057234]  rpc_kill_sb+0x121/0x200

Fixes: 0157d021d23a ("SUNRPC: handle RPC client pipefs dentries by network namespace aware routines")
Signed-off-by: felix 
Signed-off-by: Trond Myklebust 
Signed-off-by: Sasha Levin

nfsd: fix double fget() bug in __write_ports_addfd()

2023-06-09T08:34:04+00:00

[ Upstream commit c034203b6a9dae6751ef4371c18cb77983e30c28 ]

The bug here is that you cannot rely on getting the same socket
from multiple calls to fget() because userspace can influence
that.  This is a kind of double fetch bug.

The fix is to delete the svc_alien_sock() function and instead do
the checking inside the svc_addsock() function.

Fixes: 3064639423c4 ("nfsd: check passed socket's net matches NFSd superblock's one")
Signed-off-by: Dan Carpenter 
Reviewed-by: NeilBrown 
Reviewed-by: Jeff Layton 
Signed-off-by: Chuck Lever 
Signed-off-by: Sasha Levin

SUNRPC: always free ctxt when freeing deferred request

2023-05-24T16:32:45+00:00

[ Upstream commit 948f072ada23e0a504c5e4d7d71d4c83bd0785ec ]

Since the ->xprt_ctxt pointer was added to svc_deferred_req, it has not
been sufficient to use kfree() to free a deferred request.  We may need
to free the ctxt as well.

As freeing the ctxt is all that ->xpo_release_rqst() does, we repurpose
it to explicit do that even when the ctxt is not stored in an rqst.
So we now have ->xpo_release_ctxt() which is given an xprt and a ctxt,
which may have been taken either from an rqst or from a dreq.  The
caller is now responsible for clearing that pointer after the call to
->xpo_release_ctxt.

We also clear dr->xprt_ctxt when the ctxt is moved into a new rqst when
revisiting a deferred request.  This ensures there is only one pointer
to the ctxt, so the risk of double freeing in future is reduced.  The
new code in svc_xprt_release which releases both the ctxt and any
rq_deferred depends on this.

Fixes: 773f91b2cf3f ("SUNRPC: Fix NFSD's request deferral on RDMA transports")
Signed-off-by: NeilBrown 
Reviewed-by: Jeff Layton 
Signed-off-by: Chuck Lever 
Signed-off-by: Sasha Levin

SUNRPC: remove the maximum number of retries in call_bind_status

2023-05-11T14:03:35+00:00

[ Upstream commit 691d0b782066a6eeeecbfceb7910a8f6184e6105 ]

Currently call_bind_status places a hard limit of 3 to the number of
retries on EACCES error. This limit was done to prevent NLM unlock
requests from being hang forever when the server keeps returning garbage.
However this change causes problem for cases when NLM service takes
longer than 9 seconds to register with the port mapper after a restart.

This patch removes this hard coded limit and let the RPC handles
the retry based on the standard hard/soft task semantics.

Fixes: 0b760113a3a1 ("NLM: Don't hang forever on NLM unlock requests")
Reported-by: Helen Chao 
Tested-by: Helen Chao 
Signed-off-by: Dai Ngo 
Reviewed-by: Jeff Layton 
Signed-off-by: Anna Schumaker 
Signed-off-by: Sasha Levin

SUNRPC: ensure the matching upcall is in-flight upon downcall

2023-01-12T11:01:56+00:00

[ Upstream commit b18cba09e374637a0a3759d856a6bca94c133952 ]

Commit 9130b8dbc6ac ("SUNRPC: allow for upcalls for the same uid
but different gss service") introduced `auth` argument to
__gss_find_upcall(), but in gss_pipe_downcall() it was left as NULL
since it (and auth->service) was not (yet) determined.

When multiple upcalls with the same uid and different service are
ongoing, it could happen that __gss_find_upcall(), which returns the
first match found in the pipe->in_downcall list, could not find the
correct gss_msg corresponding to the downcall we are looking for.
Moreover, it might return a msg which is not sent to rpc.gssd yet.

We could see mount.nfs process hung in D state with multiple mount.nfs
are executed in parallel.  The call trace below is of CentOS 7.9
kernel-3.10.0-1160.24.1.el7.x86_64 but we observed the same hang w/
elrepo kernel-ml-6.0.7-1.el7.

PID: 71258  TASK: ffff91ebd4be0000  CPU: 36  COMMAND: "mount.nfs"
 #0 [ffff9203ca3234f8] __schedule at ffffffffa3b8899f
 #1 [ffff9203ca323580] schedule at ffffffffa3b88eb9
 #2 [ffff9203ca323590] gss_cred_init at ffffffffc0355818 [auth_rpcgss]
 #3 [ffff9203ca323658] rpcauth_lookup_credcache at ffffffffc0421ebc
[sunrpc]
 #4 [ffff9203ca3236d8] gss_lookup_cred at ffffffffc0353633 [auth_rpcgss]
 #5 [ffff9203ca3236e8] rpcauth_lookupcred at ffffffffc0421581 [sunrpc]
 #6 [ffff9203ca323740] rpcauth_refreshcred at ffffffffc04223d3 [sunrpc]
 #7 [ffff9203ca3237a0] call_refresh at ffffffffc04103dc [sunrpc]
 #8 [ffff9203ca3237b8] __rpc_execute at ffffffffc041e1c9 [sunrpc]
 #9 [ffff9203ca323820] rpc_execute at ffffffffc0420a48 [sunrpc]

The scenario is like this. Let's say there are two upcalls for
services A and B, A -> B in pipe->in_downcall, B -> A in pipe->pipe.

When rpc.gssd reads pipe to get the upcall msg corresponding to
service B from pipe->pipe and then writes the response, in
gss_pipe_downcall the msg corresponding to service A will be picked
because only uid is used to find the msg and it is before the one for
B in pipe->in_downcall.  And the process waiting for the msg
corresponding to service A will be woken up.

Actual scheduing of that process might be after rpc.gssd processes the
next msg.  In rpc_pipe_generic_upcall it clears msg->errno (for A).
The process is scheduled to see gss_msg->ctx == NULL and
gss_msg->msg.errno == 0, therefore it cannot break the loop in
gss_create_upcall and is never woken up after that.

This patch adds a simple check to ensure that a msg which is not
sent to rpc.gssd yet is not chosen as the matching upcall upon
receiving a downcall.

Signed-off-by: minoura makoto 
Signed-off-by: Hiroshi Shimamoto 
Tested-by: Hiroshi Shimamoto 
Cc: Trond Myklebust 
Fixes: 9130b8dbc6ac ("SUNRPC: allow for upcalls for same uid but different gss service")
Signed-off-by: Trond Myklebust 
Signed-off-by: Sasha Levin