Issues with Big Sur & NFS

DanieleCr,

Please contact Apple Support directly with this issue.

Be as explicit as possible that it is an engineering issue with Big Sur, and that you have diagnostic information and the aforementioned packet dumps.

Contact - Official Apple Support

Many of us do SMB transfers all the time, but there seems to be something about your configuration that exacerbates this particular issue, and of course Apple can't test every possible configuration.

In particular, your kernel panic points to an issue within a driver or the networking code somewhere where it is freeing memory but is retaining a reference to the freed memory and is improperly modifying the memory contents after having freed it.

I have issues with smb too; for only some files the transfer from the share to the mac hangs with error -8084 (or sometimes crashes with a kernel panic).

"Zone element 0xffffff9379469600 was modified after free for zone kext.kalloc.512: " "Expected element to be cleared"@/AppleInternal/BuildRoot/Library/Caches/com.apple.xbs/Sources/xnu/xnu-7195.50.3.201.1/osfmk/kern/zalloc.c:1968

Smb server is linux with samba 4.13.2-1

Same files with the same server and same mac transfer with no issues on Catalina.

I'm having this issue since beta 7 (if I remember well) and it's here also in 11.1 beta 1.

I had to switch termporary to nfs which in my case is stable (nfs to local and local to nfs).

I have to stay with Catalina because of this issue.

It's simply bugged!

Me too, I reinstalled the os several times during betas starting from a clean hd (always), hoping everytime that the issue was solved.

My issue may be different but I think it's related since my transfers hang too, but the os doesn't freeze.

It's simply unacceptable what Apple is doing, such basic features should be tested on the compatible hardware before releasing the os.

But hey! we have new emoticons and new icons! Simply crazy...

You know apple's mind, closed os, closed hardware, for sure smb/nfs will work good between macs (probably?).

[Edited by Moderator]

Thanks William for your kind reply, I will try to get in contact directly with apple and see what we can do together.

Yes, the kernel panic points to com.apple.filesystems.smbfs, but as said I don't always have a kernel panic, only sometimes 1 time out of 50? Most of the time with the following configuration the error is -8084 (and that happens only for some files, always the same, and it doesn't matter the size of the problematic file, because I'm able to transfer other files, bigger or smaller in size, so it's very difficult to understand what is happening in the background).

For these problematic files, the usual behavior is always the same, the transfer seems to start, it stops at exactly 67,1 MB, then it hangs and the system throws -8084 error.

By forcing sync, it fails too, but the transfer hangs with the same error at a multiple of 67,1 MB (if I remember well at 134,2 MB)...very strange..

In Catalina latest stable all is working without issues.

I think I don't have any particular configuration, here is my samba.conf on the linux box:

[global]
access based share enum = yes
bind interfaces only = yes
interfaces = lo enp6s0

[2TB]
path = /media/2TB
browsable = yes
Force User = nobody
valid users = user1, user2
write list = user1, user2
vfs objects =

[6TB]
path = /media/6TB
browsable = yes
Force User = nobody
valid users = user1, user2
write list = user1, user2
vfs objects =

[VM]
path = /media/VM
browsable = yes
Force User = nobody
valid users = user1, user2
write list = user1, user2
vfs objects =

I had this issue as well until I increased the rwsize to 65536 and it seems to go away. I also use async as it improve performance since I've encountered sync causing file transfer to freeze especially very large files.

The only problem I'm having is that Big Sur's Finder is reporting different available size on my NAS. My NAS have 8TB available space and Big Sur on my iMac is reporting 60M available. What's more strange is that my macbook with Catalina is reporting 8TB available space. Both iMac and macbook are using the same NFS configurations. I tried to turn off Spotlight and even tried to re-index to no avail. Are you seeing Finder misreporting the available space on your network drive?

@stkitchin

Thank you very much man!This fixed the issue for me.

I added this line in the [global] section of my smb server:

socket options = TCP_NODELAY IPTOS_LOWDELAY SO_RCVBUF=65536 SO_SNDBUF=65536

No more -8084 error nor kernel panics.

Thank you, very much appreciated!

I also dumped wireshark packets for a successful and unsuccessful transfer (smb); dumps are available here:

https://workupload.com/file/ajjpuxKNUUk