Date: Mon, 15 Jan 2024 07:04:44 -0800 From: Rick Macklem <rick.macklem@gmail.com> To: Peter Blok <pblok@bsd4all.org> Cc: FreeBSD User <freebsd@walstatt-de.de>, Cy Schubert <Cy.Schubert@cschubert.com>, Ronald Klop <ronald-lists@klop.ws>, FreeBSD CURRENT <freebsd-current@freebsd.org> Subject: Re: NFSv4 crash of CURRENT Message-ID: <CAM5tNy74S3Geo0iENXycMUTNLv=Y=2cCoOxtNwdMFs35t3Kubg@mail.gmail.com> In-Reply-To: <683EF50F-6665-4664-A7CE-1EFE50076FB0@bsd4all.org> References: <20240113193324.3fd54295@thor.intern.walstatt.dynvpn.de> <1369645989.13766.1705178331205@localhost> <CAM5tNy5aat8vUn2fsX9jV=D9yGZdnO20Q0Ea7qtszx%2BzSES2bw@mail.gmail.com> <20240115043412.B6998C8@slippy.cwsent.com> <20240115064704.611fe0c4@thor.intern.walstatt.dynvpn.de> <D6D597BF-A98B-4864-B754-CB0B9A7A5A66@bsd4all.org> <683EF50F-6665-4664-A7CE-1EFE50076FB0@bsd4all.org>
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On Mon, Jan 15, 2024 at 2:53=E2=80=AFAM Peter Blok <pblok@bsd4all.org> wrot=
e:
>
> Hi,
>
> Forgot to mention I=E2=80=99m on 13-stable. The fix that is causing the c=
rash with automounted NFS is:
>
> commit cc5cda1dbaa907ce52074f47264cc45b5a7d6c8b
> Author: Konstantin Belousov <kib@FreeBSD.org>
> Date: Tue Jan 2 00:22:44 2024 +0200
>
> nfsclient: limit situations when we do unlocked read-ahead by nfsiod
>
> (cherry picked from commit 70dc6b2ce314a0f32755005ad02802fca7ed186e)
>
> When I remove the fix, the problem is gone. Add it back and the crash hap=
pens.
Kostik has already come up with a probable fix. If you want it right
away, here it is,
but he'll probably commit it soon anyhow:
diff --git a/sys/fs/nfsclient/nfs_clbio.c b/sys/fs/nfsclient/nfs_clbio.c
index c027d7d7c3fd..1cf45bb0c924 100644
--- a/sys/fs/nfsclient/nfs_clbio.c
+++ b/sys/fs/nfsclient/nfs_clbio.c
@@ -414,6 +414,18 @@ nfs_bioread_check_cons(struct vnode *vp, struct
thread *td, struct ucred *cred)
return (error);
}
+static bool
+ncl_bioread_dora(struct vnode *vp)
+{
+ vm_object_t obj;
+
+ obj =3D vp->v_object;
+ if (obj =3D=3D NULL)
+ return (true);
+ return (!vm_object_mightbedirty(vp->v_object) &&
+ vp->v_object->un_pager.vnp.writemappings =3D=3D 0);
+}
+
/*
* Vnode op for read using bio
*/
@@ -486,9 +498,7 @@ ncl_bioread(struct vnode *vp, struct uio *uio, int
ioflag, struct ucred *cred)
* unlocked read by nfsiod could obliterate changes
* done by userspace.
*/
- if (nmp->nm_readahead > 0 &&
- !vm_object_mightbedirty(vp->v_object) &&
- vp->v_object->un_pager.vnp.writemappings =3D=3D 0) {
+ if (nmp->nm_readahead > 0 && ncl_bioread_dora(vp)) {
for (nra =3D 0; nra < nmp->nm_readahead && nra < seqcou=
nt &&
(off_t)(lbn + 1 + nra) * biosize < nsize; nra++) {
rabn =3D lbn + 1 + nra;
@@ -675,9 +685,7 @@ ncl_bioread(struct vnode *vp, struct uio *uio, int
ioflag, struct ucred *cred)
* directory offset cookie of the next block.)
*/
NFSLOCKNODE(np);
- if (nmp->nm_readahead > 0 &&
- !vm_object_mightbedirty(vp->v_object) &&
- vp->v_object->un_pager.vnp.writemappings =3D=3D 0 &&
+ if (nmp->nm_readahead > 0 && ncl_bioread_dora(vp) &&
(bp->b_flags & B_INVAL) =3D=3D 0 &&
(np->n_direofoffset =3D=3D 0 ||
(lbn + 1) * NFS_DIRBLKSIZ < np->n_direofoffset) &&
rick
ps: It appears that autofs causes the directory to be read before it
is open'd for
some reason. I've never looked at autofs.
>
> Peter
>
> On 15 Jan 2024, at 09:31, Peter Blok <pblok@bsd4all.org> wrote:
>
> Hi,
>
> I do have a crash on a NFS client with stable of today (4c4633fdffbe8e4b6=
d328c2bc9bb3edacc9ab50a). It is also autofs related. Maybe it is the same p=
roblem.
>
> I have ports automounted on /am/ports. When I do cd /am/ports/sys and typ=
e tab to autocomplete it crashes with the below stack trace. If I plainly m=
ount ports on /usr/ports and do the same everything works. I am using NFSv3
>
> Peter
>
>
>
>
> Fatal trap 12: page fault while in kernel mode
> cpuid =3D 2; apic id =3D 04
> fault virtual address =3D 0x89
> fault code =3D supervisor read data, page not present
> instruction pointer =3D 0x20:0xffffffff809645d4
> stack pointer =3D 0x28:0xfffffe00acadb830
> frame pointer =3D 0x28:0xfffffe00acadb830
> code segment =3D base 0x0, limit 0xfffff, type 0x1b
> =3D DPL 0, pres 1, long 1, def32 0, gran 1
> processor eflags =3D interrupt enabled, resume, IOPL =3D 0
> current process =3D 6869 (csh)
> trap number =3D 12
> panic: page fault
> cpuid =3D 2
> time =3D 1705306940
> KDB: stack backtrace:
> #0 0xffffffff806232f5 at kdb_backtrace+0x65
> #1 0xffffffff805d7a02 at vpanic+0x152
> #2 0xffffffff805d78a3 at panic+0x43
> #3 0xffffffff809d58ad at trap_fatal+0x38d
> #4 0xffffffff809d58ff at trap_pfault+0x4f
> #5 0xffffffff809af048 at calltrap+0x8
> #6 0xffffffff804c7a7e at ncl_bioread+0xb7e
> #7 0xffffffff804b9d90 at nfs_readdir+0x1f0
> #8 0xffffffff8069c61a at vop_sigdefer+0x2a
> #9 0xffffffff809f8ae0 at VOP_READDIR_APV+0x20
> #10 0xffffffff81ce75de at autofs_readdir+0x2ce
> #11 0xffffffff809f8ae0 at VOP_READDIR_APV+0x20
> #12 0xffffffff806c3002 at kern_getdirentries+0x222
> #13 0xffffffff806c33a9 at sys_getdirentries+0x29
> #14 0xffffffff809d6180 at amd64_syscall+0x110
> #15 0xffffffff809af95b at fast_syscall_common+0xf8
>
>
>
> On 15 Jan 2024, at 06:46, FreeBSD User <freebsd@walstatt-de.de> wrote:
>
> Am Sun, 14 Jan 2024 20:34:12 -0800
> Cy Schubert <Cy.Schubert@cschubert.com> schrieb:
>
> In message <CAM5tNy5aat8vUn2fsX9jV=3DD9yGZdnO20Q0Ea7qtszx+zSES2bw@mail.gm=
ail.c
> om>
> , Rick Macklem writes:
>
> On Sat, Jan 13, 2024 at 12:39=3DE2=3D80=3DAFPM Ronald Klop <ronald-lists@=
klop.ws>=3D
> wrote:
>
>
>
> Van: FreeBSD User <freebsd@walstatt-de.de>
> Datum: 13 januari 2024 19:34
> Aan: FreeBSD CURRENT <freebsd-current@freebsd.org>
> Onderwerp: NFSv4 crash of CURRENT
>
> Hello,
>
> running CURRENT client (FreeBSD 15.0-CURRENT #4 main-n267556-69748e62e82a=
=3D
>
> : Sat Jan 13 18:08:32
>
> CET 2024 amd64). One NFSv4 server is same OS revision as the mentioned cl=
=3D
>
> ient, other is FreeBSD
>
> 13.2-RELEASE-p8. Both offer NFSv4 filesystems, non-kerberized.
>
> I can crash the client reproducable by accessing the one or other NFSv4 F=
=3D
>
> S (a simple ls -la).
>
> The NFSv4 FS is backed by ZFS (if this matters). I do not have physicla a=
=3D
>
> ccess to the client
>
> host, luckily the box recovers.
>
> Did you rebuild both the nfscommon and nfscl modules from the same source=
s?
> I did a commit to main that changes the interface between these two
> modules and did bump the
> __FreeBSD_version to 1500010, which should cause both to be rebuilt.
> (If you have "options NFSCL" in your kernel config, both should have
> been rebuilt as a part of
> the kernel build.)
>
>
> Is anyone by chance seeing autofs in the backtrace too?
>
>
>
> Hello Cy Shubert,
>
> I forgot to mention that those crashes occur with autofs mounted filesyst=
ems. Good question,
> by the way, I will check whether crashes also happen when mounting the tr=
adidional way.
>
> Kind regards,
>
> oh
>
> --
> O. Hartmann
>
>
>
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