race in autofs / nfs

From: Olaf Hering (olh@suse.de)
Date: Sun Feb 11 2001 - 15:17:01 EST


there is a race in 2.4.1 and 2.4.2-pre3 in autofs/nfs.
When the cwd is on the nfs mounted server (== busy) and you try to
reboot the shutdown hangs in "rcautofs stop". I can reproduce it everytime.

I attach a screen log and a decoded sysrq output. It is not related to
that killproc, it hangs right now in automount <-> kupdate (with kernel

kupdate 6 0 0 -1 ?00000000 c307a000 0 current
automoun 1525 31480 503680 54 u0176a368 df3e6000 1 current

there is a spinlock message:
_spin_lock(c021f6e4) CPU#1 NIP c01b8220 holder: cpu 1 pc E126BF28

c021f6e4 is not in the System.map, but c01b8220 is
c01b817c T memparse
c01b8200 T atomic_dec_and_lock
c01b9a5c t cleanup_proc_rtas

The attached log is kernel 2.4.2-pre3.
killproc 1701 1030738 16491808 106 u0178d5c8 c7de6000 0 current
automoun 1705 1036120 16577920 54 u0176a368 c7b46000 1 current
_spin_lock(c022279c) CPU#1 NIP c01b7c5c holder: cpu 1 pc E126BF28
SysRq: Emergency Sync

_spin_lock(c022279c) CPU#0 NIP c005d920 holder: cpu 1 pc E126BF28
_spin_lock(c022279c) CPU#1 NIP c01b7c5c holder: cpu 1 pc E126BF28

c01b7c5c is again atomic_dec_and_lock and c005d920 is d_lookup.

The system is a 2way RS/6000, 2gig ram.

Linux cantaloupe 2.4.1-SMP #1 SMP Sun Feb 11 13:02:05 GMT 2001 ppc
Kernel modules 2.4.1
Gnu C 2.95.2
Gnu Make 3.79.1
Linux C Library x 1 root root 1499361 Feb 9 02:50
Dynamic linker ldd (GNU libc) 2.2
Procps 2.0.7
Mount 2.10q
Net-tools 1.57
Kbd 1.02
Sh-utils 2.0
Modules Loaded nfsd autofs4 ipv6

Any ideas what could be wrong?

Gruss Olaf

 $ man clone

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This archive was generated by hypermail 2b29 : Thu Feb 15 2001 - 21:00:17 EST