M5 kernel panic skmem_slab_free_locked in the presence of a network system extension

Question

Created May ’26

Replies 6

Boosts 0

Participants 3

I've seen a number of similar posts from other network system extension developers reporting kernel panics on M5 devices in macOS. These kernel panics occur when network system extensions are enabled and are not observed on earlier mac platforms or versions of macOS.

Reference: https://developer.apple.com/forums/thread/821372

In this post, it appears like Apple is aware of a problem as noted by Kevin Elliott in versions of macOS. Do we know if there is any way to work around this problem (short of not enabling a network filter) until a fix is available?

Answer 1

JFreemanSecDev OP

May ’26

"panicProcessingFlags" : "0x0", "product" : "Mac17,9", "kernel" : "Darwin Kernel Version 25.4.0: Thu Mar 19 19:33:50 PDT 2026; root:xnu-12377.101.15~1/RELEASE_ARM64_T6050", "socRevision" : "11", "panicString" : "panic(cpu 9 caller 0xfffffe003d586e8c): skmem_slab_free_locked: attempt to free invalid or already-freed obj 0xf1fffe2155039800 on skm 0xf5fffe2be9093600 @skmem_slab.c:646\nDebugger message: panic\nMemory ID: 0x1\nOS release type: User\nOS version: 25E253\nKernel version: Darwin Kernel Version 25.4.0

Answer 2

DTS Engineer OP

Apple

May ’26

In this post, it appears like Apple is aware of a problem as noted by Kevin Elliott in versions of macOS. Do we know if there is any way to work around this problem (short of not enabling a network filter) until a fix is available?

I'm not aware of any workaround. The issue is pretty fundamental to the way packets are moved in and out of the kernel, so I don't think there's any way the filter could avoid it.

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Kevin Elliott
DTS Engineer, CoreOS/Hardware

Answer 3

JFreemanSecDev OP

May ’26

Is Apple planning on an OS update to address this issue?

Answer 4

DTS Engineer OP

Apple

May ’26

Curious on timing — is there any indication whether a fix will make it into 26.5 GA, or are we looking at a supplemental 26.4.x update?

Please test this again on the latest seed, macOS 26.5 RC (25F71). I believe this should resolve the issue.

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Kevin Elliott
DTS Engineer, CoreOS/Hardware

Answer 5

Aayu OP

1w

I can confirm that I am running macOS 26.5 build 25F71. I experienced two kernel panics on this build. Both panic logs identify the panicked task as com.objective-see.lulu.extension.

I can provide the panic logs if they would be useful.

Mac model: Mac17,3 macOS build: 25F71 LuLu: latest available version Number of observed panics: 2

Answer 6

DTS Engineer OP

Apple

1w

I can confirm that I am running macOS 26.5 build 25F71. I experienced two kernel panics on this build. Both panic logs identify the panicked task as com.objective-see.lulu.extension.

The summary of the situation is that there are multiple issues involved and we shipped fixes in both 26.5 and 26.6. However, it appears there are still other panics involving the same component set and we're currently investigating those. Note that the chain of fixes we've shipped means that testing needs to be focused on our latest seed releases, not our release builds.

I'm actively tracking this issue on this thread, so please post any future follow-up questions there.

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Kevin Elliott
DTS Engineer, CoreOS/Hardware