Date: Mon, 30 May 2022 04:31:10 +0000 From: Rick Macklem <rmacklem@uoguelph.ca> To: Kurt Jaeger <pi@freebsd.org> Cc: "freebsd-fs@freebsd.org" <freebsd-fs@freebsd.org> Subject: Re: FreeBSD 12.3/13.1 NFS client hang Message-ID: <YQBPR0101MB97429DD260F3DBDF64DD07D9DDDD9@YQBPR0101MB9742.CANPRD01.PROD.OUTLOOK.COM> In-Reply-To: <YpPJOchbcMvKUfed@fc.opsec.eu> References: <YpEwxdGCouUUFHiE@shipon.lysator.liu.se> <YQBPR0101MB9742280313FC17543132A61CDDD89@YQBPR0101MB9742.CANPRD01.PROD.OUTLOOK.COM> <YpHZb0fgsmbBrxD8@fc.opsec.eu> <YQBPR0101MB9742B91118878E58691DB94CDDDB9@YQBPR0101MB9742.CANPRD01.PROD.OUTLOOK.COM> <YQBPR0101MB9742D1CC394CB37C135A94E3DDDB9@YQBPR0101MB9742.CANPRD01.PROD.OUTLOOK.COM> <YpPJOchbcMvKUfed@fc.opsec.eu>
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Kurt Jaeger <pi@freebsd.org> wrote:=0A= [stuff snipped]=0A= >=0A= > Given that simple NFS mounts and editing with vi on nfs mounts should=0A= > be very basic use-cases, it's time to find ways to debug this 8-(=0A= To find out what processes are holding locked NFS vnode...=0A= Run a kernel with the debugger built into it.=0A= options DDB=0A= options KDB=0A= =0A= # sysctl debug.kdb.alt_break_to_debugger=3D1=0A= =0A= Then, when the hang has occurred, go to the console.=0A= Type <ctrl><alt><esc>=0A= You should go into the debugger:=0A= db>=0A= Then type "show alllocks".=0A= You are looking for the pids of the processes that hold NFS vnode locks.=0A= db> continue=0A= - Allows the system to run again.=0A= =0A= Then look through the output of "ps axHl" for the processes found above=0A= and see what they are sleeping on.=0A= (My hunch is that at least one of them is sleeping on "vmopar", but it=0A= is just a hunch.)=0A= =0A= These processes are your problem. Figure out how to stop them from=0A= sleeping on something else while holding an NFS vnode lock and you've=0A= fixed your problem. (Do not assume it is an NFS problem. I'm pretty sure=0A= it is not caused by NFS.)=0A= =0A= rick=0A= =0A= > This also implies that switching from soft->hard won't fix the problem.= =0A= =0A= Thanks for the encouragement 8-}=0A= =0A= > In summary, I don't think your hang is anything like Andreas's, rick=0A= =0A= I'll report as soon as I have a another hang.=0A= =0A= --=0A= pi@FreeBSD.org +49 171 3101372 Now what ?=0A= =0A=
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