Re: nfs: panic: fsync: vnode is not exclusive locked but should be

On Wed, 27 Aug 2025, Konstantin Belousov wrote:

> On Wed, Aug 27, 2025 at 01:18:32PM +0000, Bjoern A. Zeeb wrote:
>> Just netbooted a main (0d843cc2e2a373f01f) GENERIC to do some testing on
>> a board I rarely use before pushing changes and got the below.
>> Has this been fixed already?
>>
>> ...
>> Last login: Sun May 25 19:37:45 on ttyu0
>> VNASSERT failed: locked not true at /usr/src/bz_wifi_precommit_testing/sys/kern/vfs_subr.c:5795 (assert_vop_elocked)
>> 0xfffff8000761b000: type VREG state VSTATE_CONSTRUCTED op 0xffffffff81aad768
>>     usecount 2, writecount 0, refcount 3 seqc users 0
>>     hold count flags ()
>>     flags (VV_VMSIZEVNLOCK|VMP_LAZYLIST)
>>     v_object 0xfffff80005d991f0 ref 0 pages 1 cleanbuf 0 dirtybuf 1
>>     lock type nfs: SHARED (count 1)
>> Aug 27 13:16:38         fapu2e4b login[19ileid 18620252 fsid 0x3a3a00ff01
>> panic: fsync: vnode is not exclusive locked but should be
>> cpuid = 3
>> time = 1756300598
>> KDB: stack backtrace:
>> db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe0067d3a4c0
>> vpanic() at vpanic+0x136/frame 0xfffffe0067d3a5f0
>> panic() at panic+0x43/frame 0xfffffe0067d3a650
>> vop_fsync_debugprepost() at vop_fsync_debugprepost+0x124/frame 0xfffffe0067d3a690
>> VOP_FSYNC_APV() at VOP_FSYNC_APV+0x23/frame 0xfffffe0067d3a6b0
>> bufsync() at bufsync+0x3b/frame 0xfffffe0067d3a6e0
>> bufobj_invalbuf() at bufobj_invalbuf+0x24f/frame 0xfffffe0067d3a740
>> ncl_vinvalbuf() at ncl_vinvalbuf+0x100/frame 0xfffffe0067d3a7b0
>> nlm_advlock_internal() at nlm_advlock_internal+0xa7/frame 0xfffffe0067d3aaf0
>> nlm_advlock() at nlm_advlock+0x2d/frame 0xfffffe0067d3ab10
>> nfs_advlock() at nfs_advlock+0x1d0/frame 0xfffffe0067d3ac30
>> vop_sigdefer() at vop_sigdefer+0x30/frame 0xfffffe0067d3ac60
>> VOP_ADVLOCK_APV() at VOP_ADVLOCK_APV+0x51/frame 0xfffffe0067d3ac90
>> vn_closefile() at vn_closefile+0x9a/frame 0xfffffe0067d3ad10
>> _fdrop() at _fdrop+0x1a/frame 0xfffffe0067d3ad30
>> closef() at closef+0x1e3/frame 0xfffffe0067d3adc0
>> closefp_impl() at closefp_impl+0x71/frame 0xfffffe0067d3ae00
>> amd64_syscall() at amd64_syscall+0x169/frame 0xfffffe0067d3af30
>> fast_syscall_common() at fast_syscall_common+0xf8/frame 0xfffffe0067d3af30
>> --- syscall (6, FreeBSD ELF64, close), rip = 0x1ea0dba28cca, rsp = 0x1ea0d6def6b8, rbp = 0x1ea0d6def6e0 ---
>> KDB: enter: panic
>> [ thread pid 1955 tid 100182 ]
>> Stopped at      kdb_enter+0x33: movq    $0,0x1222d22(%rip)
>> db> show alllocks
>> Process 1955 (login) thread 0xfffff80005dda000 (100182)
>> exclusive lockmgr nfsupg (nfsupg) r = 0 (0xfffffe006b1557e0) locked @ /usr/src/bz_wifi_precommit_testing/sys/fs/nfsclient/nfs_clsubs.c:146
>> shared lockmgr nfs (nfs) r = 0 (0xfffff8000761b070) locked @ /usr/src/bz_wifi_precommit_testing/sys/fs/nfsclient/nfs_clvnops.c:3477
>> Process 1817 (syslogd) thread 0xfffff80005d85780 (100108)
>> exclusive lockmgr nfs (nfs) r = 0 (0xfffff800447a33e0) locked @ /usr/src/bz_wifi_precommit_testing/sys/kern/vfs_vnops.c:1243
>>
>
> You are using nfslockd, right?
> Try this.
>
> commit 881d724a671caa628407373faf0b87a70bfb3218
> Author: Konstantin Belousov <kib@FreeBSD.org>
> Date:   Wed Aug 27 19:57:06 2025 +0300
>
>    nfs client: switch nfs_advlock() to use exclusive vnode lock
>
>    It eliminates the need to upgrade the lock in the function.
>    More importantly, the calls to nfs_advlock_p()/nlm_advlock() sometimes
>    flush buffers, which requires exclusive locking.
>
>    Reported by:    bz
>
> diff --git a/sys/fs/nfsclient/nfs_clvnops.c b/sys/fs/nfsclient/nfs_clvnops.c
> index a8b06fdb261b..eee571a04821 100644
> --- a/sys/fs/nfsclient/nfs_clvnops.c
> +++ b/sys/fs/nfsclient/nfs_clvnops.c
> @@ -3474,7 +3474,7 @@ nfs_advlock(struct vop_advlock_args *ap)
> 	u_quad_t size;
> 	struct nfsmount *nmp;
>
> -	error = NFSVOPLOCK(vp, LK_SHARED);
> +	error = NFSVOPLOCK(vp, LK_EXCLUSIVE);
> 	if (error != 0)
> 		return (EBADF);
> 	nmp = VFSTONFS(vp->v_mount);
> @@ -3511,11 +3511,6 @@ nfs_advlock(struct vop_advlock_args *ap)
> 			cred = p->p_ucred;
> 		else
> 			cred = td->td_ucred;
> -		NFSVOPLOCK(vp, LK_UPGRADE | LK_RETRY);
> -		if (VN_IS_DOOMED(vp)) {
> -			error = EBADF;
> -			goto out;
> -		}
>
> 		/*
> 		 * If this is unlocking a write locked region, flush and
>

This booted and I could log in at least once now.

Thank you!

-- 
Bjoern A. Zeeb                                                     r15:7