linux-kernel - Re: ls input/output error ("NFS: readdir(/) returns -5") on krb5 NFSv4 client using SHA2

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Message-ID: <aRZL8kbmfbssOwKF@eldamar.lan>
Date: Thu, 13 Nov 2025 22:21:54 +0100
From: Salvatore Bonaccorso <carnil@...ian.org>
To: Chuck Lever <chuck.lever@...cle.com>
Cc: "Tyler W. Ross" <TWR@...erwross.com>,
	"1120598@...s.debian.org" <1120598@...s.debian.org>,
	Jeff Layton <jlayton@...nel.org>, NeilBrown <neil@...wn.name>,
	Scott Mayhew <smayhew@...hat.com>,
	Steve Dickson <steved@...hat.com>,
	Salvatore Bonaccorso <carnil@...ian.org>,
	Olga Kornievskaia <okorniev@...hat.com>,
	Dai Ngo <Dai.Ngo@...cle.com>, Tom Talpey <tom@...pey.com>,
	Trond Myklebust <trondmy@...nel.org>,
	Anna Schumaker <anna@...nel.org>, linux-nfs@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: ls input/output error ("NFS: readdir(/) returns -5") on krb5
 NFSv4 client using SHA2

Hi Chuck,

On Thu, Nov 13, 2025 at 12:47:23PM -0500, Chuck Lever wrote:
> On 11/13/25 12:16 PM, Tyler W. Ross wrote:
> > Thanks, Chunk.
> > 
> > Suggested trace-cmd report from the client follows. Last 3 lines appear salient, but I've included the full report just in case.
> > 
> >           <idle>-0     [001] ..s2.   270.327040: xs_data_ready:        peer=[10.108.2.102]:2049
> >    kworker/u16:0-12    [001] ...1.   270.327048: xprt_lookup_rqst:     peer=[10.108.2.102]:2049 xid=0x7b569c7a status=0
> >    kworker/u16:0-12    [001] ...2.   270.327050: rpc_task_wakeup:      task:00000008@...00005 flags=MOVEABLE|DYNAMIC|SENT|NORTO|CRED_NOREF runstate=0x6 status=0 timeout=15000 queue=xprt_pending
> >    kworker/u16:0-12    [001] .....   270.327054: xs_stream_read_request: peer=[10.108.2.102]:2049 xid=0x7b569c7a copied=988 reclen=988 offset=988
> >    kworker/u16:0-12    [001] .....   270.327055: xs_stream_read_data:  peer=[10.108.2.102]:2049 err=-11 total=992
> >               ls-969   [003] .....   270.327062: rpc_task_sync_wake:   task:00000008@...00005 flags=MOVEABLE|DYNAMIC|SENT|NORTO|CRED_NOREF runstate=RUNNING|0x4 status=0 action=call_status
> >               ls-969   [003] .....   270.327062: rpc_task_run_action:  task:00000008@...00005 flags=MOVEABLE|DYNAMIC|SENT|NORTO|CRED_NOREF runstate=RUNNING|0x4 status=0 action=xprt_timer
> >               ls-969   [003] .....   270.327063: rpc_task_run_action:  task:00000008@...00005 flags=MOVEABLE|DYNAMIC|SENT|NORTO|CRED_NOREF runstate=RUNNING|0x4 status=0 action=call_status
> >               ls-969   [003] .....   270.327063: rpc_task_run_action:  task:00000008@...00005 flags=MOVEABLE|DYNAMIC|SENT|NORTO|CRED_NOREF runstate=RUNNING|0x4 status=0 action=call_decode
> >               ls-969   [003] .....   270.327063: rpc_xdr_recvfrom:     task:00000008@...00005 head=[0xffff8895c29fef64,140] page=4008(88) tail=[0xffff8895c29feff0,36] len=988
> >               ls-969   [003] .....   270.327067: rpc_xdr_overflow:     task:00000008@...00005 nfsv4 READDIR requested=8 p=0xffff8895c29fefec end=0xffff8895c29feff0 xdr=[0xffff8895c29fef64,140]/4008/[0xffff8895c29feff0,36]/988
> 
> Here's the problem. This is a sign of an XDR decoding issue. If you
> capture the traffic with Wireshark, does Wireshark indicate where the
> XDR is malformed?
> 
> If it doesn't, then there is some problem with the client code. Since
> Fedora 43 is working as expected, I would guess there's a misapplied
> patch on Debian 13's kernel...?

if it is helpful: Debian follows the stable upstream releases (6.12.y
for trixie/Debian 13, right now 6.17.y for Debian unstable) and we try
to keep the patches limited which we apply on top. So far I see none
which touches net/sunrpc/. The patches applied:
https://salsa.debian.org/kernel-team/linux/-/tree/debian/6.17/forky/debian/patches?ref_type=heads
(in case this could help narrowing down more the issue).

But we could try here additionally, if Tylor has the possibility to do
so, to try directly the 6.17.7 upstream version without Debian patches
applied.

Regards,
Salvatore