Date: Mon, 31 May 2021 15:41:51 +0000 From: Rick Macklem <rmacklem@uoguelph.ca> To: Mateusz Guzik <mjguzik@gmail.com>, Dimitry Andric <dim@FreeBSD.org> Cc: FreeBSD Current <freebsd-current@freebsd.org>, Rick Macklem <rmacklem@FreeBSD.org> Subject: Re: Panics in recent NFS server Message-ID: <YQXPR0101MB0968D053FCA63BD6D1FC0E13DD3F9@YQXPR0101MB0968.CANPRD01.PROD.OUTLOOK.COM> In-Reply-To: <CAGudoHGk0mrmiLHqhfvCA596kxZa8vD1ex%2BQOgLBE0vt%2B7OJrA@mail.gmail.com> References: <EA017AF6-25C8-48FC-B52F-D83D9DD314AA@FreeBSD.org> <CAGudoHHd3QVT6mefMcELRKa7nPptjVuc=D-agoHUNY4pfOz8tg@mail.gmail.com>,<CAGudoHGk0mrmiLHqhfvCA596kxZa8vD1ex%2BQOgLBE0vt%2B7OJrA@mail.gmail.com>
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Mateusz Guzik wrote:=0A=
>On 5/31/21, Mateusz Guzik <mjguzik@gmail.com> wrote:=0A=
>> It's probably my commit d81aefa8b7dd8cbeffeda541fca9962802404983 ,=0A=
>> I'll look at this later.=0A=
>=0A=
>Well let me rephrase. While the panic was added in said commit, I=0A=
>suspect the bug is on nfs side -- it has its own namei variant which I=0A=
>suspect is managing ni_pathlen in a manner different than the=0A=
>original, it just happens to not panic on kernels prior to the above=0A=
>change.=0A=
The NFS code for lookup has not changed in a long time.=0A=
There have definitely been no changed recently.=0A=
The code should be nul terminating the path in nfsrv_parsename(),=0A=
which looks straightforward.=0A=
=0A=
However, the NFS code does not include the nul byte in the ni_pathlen,=0A=
and never has.=0A=
=0A=
Shouldn't it be:=0A=
nulchar =3D &cnp->cn_nameptr[ndp->ni_pathlen];=0A=
and not=0A=
nulchar =3D &cnp->cn_nameptr[ndp->ni_pathlen - 1];=0A=
=0A=
rick=0A=
=0A=
>=0A=
> On 5/31/21, Dimitry Andric <dim@freebsd.org> wrote:=0A=
>> Hi,=0A=
>>=0A=
>> I recently upgraded a -CURRENT NFS server from 2021-05-12 to today=0A=
>> (2021-05-31), and when the first NFS client attempted to connect, I got=
=0A=
>> this=0A=
>> panic:=0A=
>>=0A=
>> panic: lookup: expected nul at 0xfffff800104b3002; string [dim]=0A=
>>=0A=
>> cpuid =3D 0=0A=
>> time =3D 1622463863=0A=
>> KDB: stack backtrace:=0A=
>> db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame=0A=
>> 0xfffffe00747e89b0=0A=
>> vpanic() at vpanic+0x187/frame 0xfffffe00747e8a10=0A=
>> panic() at panic+0x43/frame 0xfffffe00747e8a70=0A=
>> lookup() at lookup+0xad2/frame 0xfffffe00747e8b10=0A=
>> nfsvno_namei() at nfsvno_namei+0x1a4/frame 0xfffffe00747e8bc0=0A=
>> nfsrvd_lookup() at nfsrvd_lookup+0x191/frame 0xfffffe00747e8eb0=0A=
>> nfsrvd_dorpc() at nfsrvd_dorpc+0xfab/frame 0xfffffe00747e90c0=0A=
>> nfssvc_program() at nfssvc_program+0x604/frame 0xfffffe00747e92a0=0A=
>> svc_run_internal() at svc_run_internal+0xa72/frame 0xfffffe00747e93d0=0A=
>> svc_run() at svc_run+0x250/frame 0xfffffe00747e9430=0A=
>> nfsrvd_nfsd() at nfsrvd_nfsd+0x33c/frame 0xfffffe00747e9590=0A=
>> nfssvc_nfsd() at nfssvc_nfsd+0x473/frame 0xfffffe00747e9aa0=0A=
>> sys_nfssvc() at sys_nfssvc+0xc7/frame 0xfffffe00747e9ac0=0A=
>> amd64_syscall() at amd64_syscall+0x12e/frame 0xfffffe00747e9bf0=0A=
>> fast_syscall_common() at fast_syscall_common+0xf8/frame=0A=
>> 0xfffffe00747e9bf0=0A=
>> --- syscall (155, FreeBSD ELF64, sys_nfssvc), rip =3D 0x8011aa59a, rsp =
=3D=0A=
>> 0x7fffffffe4e8, rbp =3D 0x7fffffffe780 ---=0A=
>> KDB: enter: panic=0A=
>>=0A=
>> __curthread ()=0A=
>> at /share/dim/src/freebsd/src-dim/sys/amd64/include/pcpu_aux.h:55=0A=
>> 55 __asm("movq %%gs:%P1,%0" : "=3Dr" (td) : "n" (offsetof(stru=
ct pcpu,=0A=
>> (kgdb) #0 __curthread ()=0A=
>> at /share/dim/src/freebsd/src-dim/sys/amd64/include/pcpu_aux.h:55=0A=
>> #1 doadump (textdump=3Dtextdump@entry=3D0)=0A=
>> at /share/dim/src/freebsd/src-dim/sys/kern/kern_shutdown.c:399=0A=
>> #2 0xffffffff804cca5a in db_dump (dummy=3D<optimized out>,=0A=
>> dummy2=3D<unavailable>, dummy3=3D<unavailable>, dummy4=3D<unavailabl=
e>)=0A=
>> at /share/dim/src/freebsd/src-dim/sys/ddb/db_command.c:575=0A=
>> #3 0xffffffff804cc912 in db_command (last_cmdp=3D<optimized out>,=0A=
>> cmd_table=3D<optimized out>, dopager=3Ddopager@entry=3D1)=0A=
>> at /share/dim/src/freebsd/src-dim/sys/ddb/db_command.c:482=0A=
>> #4 0xffffffff804cc58d in db_command_loop ()=0A=
>> at /share/dim/src/freebsd/src-dim/sys/ddb/db_command.c:535=0A=
>> #5 0xffffffff804cfd06 in db_trap (type=3D<optimized out>, code=3D<optim=
ized=0A=
>> out>)=0A=
>> at /share/dim/src/freebsd/src-dim/sys/ddb/db_main.c:270=0A=
>> #6 0xffffffff80c69f17 in kdb_trap (type=3Dtype@entry=3D3, code=3Dcode@e=
ntry=3D0,=0A=
>> tf=3Dtf@entry=3D0xfffffe00747e88e0)=0A=
>> at /share/dim/src/freebsd/src-dim/sys/kern/subr_kdb.c:727=0A=
>> #7 0xffffffff810d7aee in trap (frame=3D0xfffffe00747e88e0)=0A=
>> at /share/dim/src/freebsd/src-dim/sys/amd64/amd64/trap.c:576=0A=
>> #8 <signal handler called>=0A=
>> #9 kdb_enter (why=3D0xffffffff812d3d27 "panic", msg=3D<optimized out>)=
=0A=
>> at /share/dim/src/freebsd/src-dim/sys/kern/subr_kdb.c:506=0A=
>> #10 0xffffffff80c1d248 in vpanic (=0A=
>> fmt=3D0xffffffff8129dfef "%s: expected nul at %p; string [%s]\n",=0A=
>> ap=3D<optimized out>, ap@entry=3D0xfffffe00747e8a50)=0A=
>> at /share/dim/src/freebsd/src-dim/sys/kern/kern_shutdown.c:907=0A=
>> #11 0xffffffff80c1cfd3 in panic (=0A=
>> fmt=3D0xffffffff81e9b9c8 <cnputs_mtx> "=3D\t)\201\377\377\377\377")=
=0A=
>> at /share/dim/src/freebsd/src-dim/sys/kern/kern_shutdown.c:843=0A=
>> #12 0xffffffff80cfa992 in lookup (ndp=3Dndp@entry=3D0xfffffe00747e8d90)=
=0A=
>> at /share/dim/src/freebsd/src-dim/sys/kern/vfs_lookup.c:919=0A=
>> #13 0xffffffff80b33f84 in nfsvno_namei (nd=3Dnd@entry=3D0xfffffe00747e91=
00,=0A=
>> ndp=3Dndp@entry=3D0xfffffe00747e8d90, dp=3D<optimized out>,=0A=
>> dp@entry=3D0xfffff80010544380, islocked=3D<optimized out>,=0A=
>> islocked@entry=3D0,=0A=
>> exp=3Dexp@entry=3D0xfffffe00747e8fd8, p=3Dp@entry=3D0xfffffe00bbfa30=
00,=0A=
>> retdirp=3D0xfffffe00747e8e78)=0A=
>> at /share/dim/src/freebsd/src-dim/sys/fs/nfsserver/nfs_nfsdport.c:59=
7=0A=
>> #14 0xffffffff80b266a1 in nfsrvd_lookup (nd=3D0xfffffe00747e9100,=0A=
>> isdgram=3D<optimized out>, dp=3D0xfffff80010544380,=0A=
>> vpp=3D0xfffffe00747e9010,=0A=
>> fhp=3D0xfffffe00747e9074, exp=3D0xfffffe00747e8fd8)=0A=
>> at /share/dim/src/freebsd/src-dim/sys/fs/nfsserver/nfs_nfsdserv.c:60=
7=0A=
>> #15 0xffffffff80b1073b in nfsrvd_compound (nd=3D0xfffffe00747e9100,=0A=
>> isdgram=3D0,=0A=
>> tag=3D0xf <error: Cannot access memory at address 0xf>, taglen=3D6,=
=0A=
>> minorvers=3D4294967294)=0A=
>> at=0A=
>> /share/dim/src/freebsd/src-dim/sys/fs/nfsserver/nfs_nfsdsocket.c:1098=0A=
>> #16 nfsrvd_dorpc (nd=3Dnd@entry=3D0xfffffe00747e9100,=0A=
>> isdgram=3Disdgram@entry=3D0,=0A=
>> tag=3D0xf <error: Cannot access memory at address 0xf>, taglen=3D6,=
=0A=
>> minorvers=3D4294967294)=0A=
>> at=0A=
>> /share/dim/src/freebsd/src-dim/sys/fs/nfsserver/nfs_nfsdsocket.c:626=0A=
>> #17 0xffffffff80b24c44 in nfs_proc (nd=3D0xfffffe00747e9100,=0A=
>> xid=3D<optimized out>, xprt=3D0xfffff80003a14e00, rpp=3D<optimized o=
ut>)=0A=
>> at /share/dim/src/freebsd/src-dim/sys/fs/nfsserver/nfs_nfsdkrpc.c:40=
2=0A=
>> #18 nfssvc_program (rqst=3D0xfffff80010455800, xprt=3D0xfffff80003a14e00=
)=0A=
>> at /share/dim/src/freebsd/src-dim/sys/fs/nfsserver/nfs_nfsdkrpc.c:28=
8=0A=
>> #19 0xffffffff80edead2 in svc_executereq (rqstp=3D0xfffff80010455800)=0A=
>> at /share/dim/src/freebsd/src-dim/sys/rpc/svc.c:1037=0A=
>> #20 svc_run_internal (grp=3D<optimized out>, grp@entry=3D0xfffff800100e6=
100,=0A=
>> ismaster=3Dismaster@entry=3D1)=0A=
>> at /share/dim/src/freebsd/src-dim/sys/rpc/svc.c:1313=0A=
>> #21 0xffffffff80eddf80 in svc_run (pool=3D<optimized out>)=0A=
>> at /share/dim/src/freebsd/src-dim/sys/rpc/svc.c:1392=0A=
>> #22 0xffffffff80b251ec in nfsrvd_nfsd (td=3D<optimized out>,=0A=
>> td@entry=3D0xfffffe00bbfa3000, args=3Dargs@entry=3D0xfffffe00747e966=
0)=0A=
>> at /share/dim/src/freebsd/src-dim/sys/fs/nfsserver/nfs_nfsdkrpc.c:56=
1=0A=
>> #23 0xffffffff80b3ec93 in nfssvc_nfsd (td=3D0xfffffe00bbfa3000,=0A=
>> uap=3D<optimized out>)=0A=
>> at=0A=
>> /share/dim/src/freebsd/src-dim/sys/fs/nfsserver/nfs_nfsdport.c:3714=0A=
>> #24 0xffffffff80e6f647 in sys_nfssvc (td=3D0xfffffe00bbfa3000,=0A=
>> uap=3D0xfffffe00bbfa33e8)=0A=
>> at /share/dim/src/freebsd/src-dim/sys/nfs/nfs_nfssvc.c:111=0A=
>> #25 0xffffffff810d891e in syscallenter (td=3D<optimized out>)=0A=
>> at=0A=
>> /share/dim/src/freebsd/src-dim/sys/amd64/amd64/../../kern/subr_syscall.c=
:189=0A=
>> #26 amd64_syscall (td=3D0xfffffe00bbfa3000, traced=3D0)=0A=
>> at /share/dim/src/freebsd/src-dim/sys/amd64/amd64/trap.c:1156=0A=
>> #27 <signal handler called>=0A=
>> #28 0x00000008011aa59a in ?? ()=0A=
>>=0A=
>> Is anybody seeing this too? :)=0A=
>>=0A=
>> I can probably bisect, but it'll take quite a while.=0A=
>>=0A=
>> -Dimitry=0A=
>>=0A=
>>=0A=
>=0A=
>=0A=
> --=0A=
> Mateusz Guzik <mjguzik gmail.com>=0A=
>=0A=
=0A=
=0A=
--=0A=
Mateusz Guzik <mjguzik gmail.com>=0A=
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