[DragonFlyBSD - Bug #3170] repeatable nfsd crash

bugtracker-admin at leaf.dragonflybsd.org bugtracker-admin at leaf.dragonflybsd.org
Tue Jan 29 20:02:58 PST 2019

Issue #3170 has been updated by dillon.

Hmm..  Ok, you can delete vmcore.3 and kern.3, we've downloaded it.  Unfortunately it looks like the core dump was corrupt.  It unpacked as follows:

-rw-r--r--  1 2024  wheel   118793728 Jan 29 08:11 kern.3
-rw-r--r--  1 2024  wheel  1849134952 Jan 29 08:11 vmcore.3

If those sizes are correct then it might have generated a corrupt core dump.   It might be possible to try again and the next core dump winds up being ok, but sometimes when core dumps get corrupted like this the same corruption occurs on each crash.

You can test the generated core yourself.  If it is sitting in /var/crash you can do:

kgdb -n 3

and then use the 'back' command to get a stack trace, assuming it doesn't crap out.  If it says 'cannot access memory at address 0x10', then the original core was corrupt.  You can try causing another panic and generating another core.  Definitely make sure you have enough room to store the core, they can get pretty big.

Sephe and I couldn't find anything looking at the source code so at the moment we don't know what could have caused that assertion to occur.


Bug #3170: repeatable nfsd crash

* Author: tse
* Status: New
* Priority: Normal
* Assignee: 
* Category: 
* Target version: Latest stable
I created a linux vm on qemu with nfs shared from Dragonfly. Reason being so I could install the go-app-engine for google cloud. Could read/write small files to the nfs share. But running google-cloud-sdk/install.sh from the vm on the nfs share quickly causes this error:

panic: assertion "m->m_type == MT_DATA" failed in m_dup_data at /usr/src/sys/kern/uipc_mbuf.c:1820
cpuid = 1
Trace beginning at frame 0xfffff802f71bf500
m_dup_data() at m_dup_data+0x12b 0xffffffff805e8a7b 
m_dup_data() at m_dup_data+0x12b 0xffffffff805e8a7b 
nfs_realign.isra.3() at nfs_realign.isra.3+0x48 0xffffffff807177c8 
nfsrv_rcv() at nfsrv_rcv+0x490 0xffffffff8071c110 
sys_nfssvc() at sys_nfssvc+0x13e7 0xffffffff8071fcf7 
syscall2() at syscall2+0x238 0xffffffff8098c0d8

I've switched from nfsd to unfsd, and that works fine. Though it took me a day of fiddling for unfsd, just because I didn't know not to run it with mountd. Hehe, such is life :)

Sorry, I'm sure it would take me many multiple months of work to think of supplying a patch for this bug

But I'm happy. It's my first time to setup an nfs share and linux vm, and now I can use them to access things from Dragonfly like google app engine, or clang sanitizers to hold my hand when I'm writing c

core.txt.3 (296 KB)

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