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Date:   Thu, 17 Mar 2022 11:32:53 +0000
From:   Hyeonggon Yoo <42.hyeyoo@gmail.com>
To:     rcu@vger.kernel.org
Cc:     "Paul E. McKenney" <paulmck@kernel.org>,
        Josh Triplett <josh@joshtriplett.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Joel Fernandes <joel@joelfernandes.org>,
        Hyeonggon Yoo <42.hyeyoo@gmail.com>,
        linux-kernel@vger.kernel.org
Subject: RCU: undefined reference to irq_work_queue
Message-ID: <YjMcZexG/kJepYDi@ip-172-31-19-208.ap-northeast-1.compute.internal>
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Hello RCU folks,

I like to use minimal configuration for kernel development.
when building with tinyconfig + CONFIG_PREEMPT=y on arm64:

ld: kernel/rcu/update.o: in function `call_rcu_tasks':
update.c:(.text+0xb2c): undefined reference to `irq_work_queue'
update.c:(.text+0xb2c): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `irq_work_queue'
make: *** [Makefile:1155: vmlinux] Error 1

It seems RCU calls irq_work_queue() without checking if CONFIG_IRQ_WORK is enabled.

-- 
Thank you, You are awesome!
Hyeonggon :-)