Date: Mon, 05 Jan 2026 08:39:29 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-arm@FreeBSD.org Subject: [Bug 292195] arm64: panic on coredump with sve instructions Message-ID: <bug-292195-7@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=292195 Bug ID: 292195 Summary: arm64: panic on coredump with sve instructions Product: Base System Version: 16.0-CURRENT Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: arm Assignee: freebsd-arm@FreeBSD.org Reporter: william.a@carrel.org Created attachment 266838 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=266838&action=edit vfp.c.patch When trying to reproduce bug 292177 on 16-CURRENT I unexpectedly encountered a kernel panic. It looks like the panic was unique to coredumping in SVE code. The coredump logic calls get_arm64_sve twice: once to get the note size, and once to get the data. The note size calculation depended on the volatile PCB_FP_SVEVALID flag. If this flag was cleared between the two calls (e.g., due to a context switch clearing the flag to comply with the ABI), the second call would expect a smaller buffer size than the first, triggering the KASSERT panic ("invalid size"). Fix this by: 1. Using pcb->pcb_svesaved != NULL (a stable indicator of SVE usage) to determine the note size. 2. Calling vfp_to_sve_sync() if SVE is not currently valid but SVE state is saved, ensuring the SVE buffer in the core dump contains the most up-to-date register values. -- You are receiving this mail because: You are the assignee for the bug.home | help
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