Re: [PATCH v17 03/13] x86/hw_breakpoints: Make DR7 updates NMI safe
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From: sashiko-bot@kernel.org
Date: 2026-09-22 04:40:34
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kvm, linux-perf-users
From: Jinchao Wang <redacted> Hardware breakpoint installation and removal run with IRQs disabled, but an NMI can still enter the same code through KGDB. The interrupted operation and the NMI can consequently claim the same slot or overwrite each other's DR7 state. Claim and release per-CPU slots with cmpxchg. Update cpu_dr7 with single-instruction per-CPU operations, and preserve hardware-first disable and hardware-last enable ordering. Add a per-CPU sequence number so interrupted DR7 writers and restore paths detect an NMI update and retry from the latest shadow state. Link: https://lore.kernel.org/all/4ee0a2efc9e8387af83286b8495b7d490247e165.1785067572.git.wangjinchao600@gmail.com/ (local) Assisted-by: Antigravity:gemini-3.8-flash Signed-off-by: Jinchao Wang <redacted> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Sashiko has reviewed this patch and found no issues. It looks great! -- Sashiko AI review · https://sashiko.dev/#/patchset/179005108298.388919.4535333252892590932.stgit@devnote2?part=3