Diagnostic query: Unexpected kernel panic on macOS Sequoia 15.1 after waking (1794527890)

[Marcus Reed]

Following the recent point release update, my system has encountered intermittent sleep/wake panics. The panic log cites IOPlatformPluginFamily and AppleThunderboltNHI assertions.

I have already tested clearing NVRAM, booted in Safe Mode to isolate third-party kexts, and disabled Power Nap. Has anyone isolated whether this is linked to external DisplayPort docks or an APFS snapshot indexing bottleneck?

[Claire Bennett]

The AppleThunderboltNHI assertion often masks a BridgeOS/T2 firmware handshake failure (analogous to iOS Error 4013/9) where the controller fails to re-enumerate the DisplayPort alt-mode path during wake. Verify the dock’s PD contract stability via pmset -g log | grep -e "PD.*Handshake" -e "Thunderbolt" and check for IOThunderboltController retries in sudo dmesg | grep -i thunderbolt. If the dock presents a USB Billboard device for firmware updates, disconnect it temporarily; a stalled Finder sync (fileproviderd holding diskarbitrationd locks) combined with a renegotiating PD contract frequently triggers the IOPlatformPluginFamily watchdog timeout.

MacBook Pro 16″ M2 Max | iPhone 16 Plus

London, UK | "Swap the USB-C cable before blaming the logic board."

[Owen Parker]

On Apple Silicon, the SMC (now SCP) exposes environmental sensors via AppleSMC/AppleARMPE; a false-positive liquid ingress flag (logged as SMC::LIQUID_DETECTED in log show --predicate 'subsystem == "com.apple.iokit.IOPlatformPluginFamily"' ) will force an immediate thermal clamp and panic on wake to protect the SoC. Rule out modem-induced wake storms by disabling “Wake for network access” and checking log show --style syslog --predicate 'process == "CommCenter"' for eSIM/5G dongle reset loops (CTCarrier changes) that prevent the AppleThunderboltNHI from reaching kIOPMDeviceIdle state. Confirm thermal sensor calibration with sudo powermetrics --samplers smc -n 1 -i 1000 looking for THRM sensor deltas > 15°C between sleep entry and wake.

iPhone 14 Pro | Apple Watch Series 10 | MagSafe Duo

Denver, CO | "Let humid USB-C ports air dry — never reach for rice."

[Nina Patel]

Sequoia 15.1’s Security Update 2024-001 patched IOAcceleratorFamily (CVE-2024-XXXX) but introduced a regression in IOSurface lifetime management when Safari’s WebContent process holds a IOSurfaceRootUserClient lock across sleep—check sudo zprint -s | grep IOSurface for leaked buffers post-wake. Simultaneously, accounts.d driven by Family Sharing keychain sync (com.apple.familysharing.sync) can spike kernel_task CPU during the DarkWake window, starving the AppleThunderboltNHI interrupt handler. Mitigate by toggling sudo mdutil -i off / temporarily to halt snapshot indexing, and disable Safari > Settings > Advanced > "Show features for web developers" to reduce WebKit background task residency during power transitions.

MacBook Pro 14″ M1 Pro (32GB) | iPhone 15 Plus

Melbourne, AU | "Verify Rapid Security Response builds right in Settings > About."

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