linux-kernel - [BUG] Possible Circular Locking Dependency (deadlock) in pcpu_alloc_mutex and might

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Message-ID: <AN6AuABUJ1wJzL8FhRfI7Koh.1.1765276660708.Hmail.2200013188@stu.pku.edu.cn>
Date: Tue, 9 Dec 2025 18:37:40 +0800 (GMT+08:00)
From: Tianyu Li <lty218@....pku.edu.cn>
To: linux-kernel <linux-kernel@...r.kernel.org>
Cc: linux-mm <linux-mm@...ck.org>, akpm <akpm@...ux-foundation.org>, 
	xujiakai2025 <xujiakai2025@...as.ac.cn>, 
	"zhaoruilin22@...ls.ucas.ac.cn" <zhaoruilin22@...ls.ucas.ac.cn>
Subject: [BUG] Possible Circular Locking Dependency (deadlock)  in pcpu_alloc_mutex and might_alloc

Hello,

Lockdep reports a possible circular locking dependency (deadlock) detected via a fuzzing framework on Linux 6.18.0-rc7, and it also appears to be reproducible on v6.18. Since the report itself is already quite clear, I don’t want to risk adding inaccurate analysis here. Instead, I have attached the relevant information and materials below for your review.

  Kernel source: https://cdn.kernel.org/pub/linux/kernel/v6.x/linux-6.18.tar.xz
  Kernel configuration: https://github.com/j1akai/KConfigFuzz_bug/raw/refs/heads/main/x86/mainline-config
  Kernel log(report): https://github.com/Wxm-233/KConfigFuzz_crashes/raw/refs/heads/main/0f85fc661af1e3c69b26b97eaaaa43d629de449c/report0
  Reproduction C Code: https://github.com/Wxm-233/KConfigFuzz_crashes/raw/refs/heads/main/0f85fc661af1e3c69b26b97eaaaa43d629de449c/repro.cprog
  Syscall sequence for reproduction (more precise): https://github.com/Wxm-233/KConfigFuzz_crashes/raw/refs/heads/main/0f85fc661af1e3c69b26b97eaaaa43d629de449c/repro.prog
  GCC info: https://github.com/Wxm-233/KConfigFuzz_crashes/raw/refs/heads/main/0f85fc661af1e3c69b26b97eaaaa43d629de449c/gccinfo

I hope this report helps in identifying and resolving the issue. Thanks for your time and attention.

Best regards.