[BUG] Possible Circular Locking Dependency (deadlock) in pcpu_alloc_mutex and might_alloc

[Tianyu Li]

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.