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Shutemov" Content-Type: text/plain; charset="UTF-8" At least on x86 KMSAN is seriously slown down by lockdep, as every pfn_valid() call (which is done on every instrumented memory access in the kernel) performs several lockdep checks, all of which, in turn, perform additional memory accesses and call KMSAN instrumentation. Right now lockdep overflows the stack under KMSAN, but even if we use reentrancy counters to avoid the recursion on the KMSAN side, the slowdown from lockdep remains big enough for the kernel to become unusable. Reported-by: Kirill A. Shutemov Closes: https://github.com/google/kmsan/issues/94 Link: https://groups.google.com/g/kasan-dev/c/ZBiGzZL36-I/m/WtNuKqP9EQAJ Signed-off-by: Alexander Potapenko --- lib/Kconfig.debug | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 59b6765d86b8f..036905cf1dbe9 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1339,7 +1339,7 @@ menu "Lock Debugging (spinlocks, mutexes, etc...)" config LOCK_DEBUGGING_SUPPORT bool - depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT + depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT && !KMSAN default y config PROVE_LOCKING -- 2.45.2.741.gdbec12cfda-goog