linux-kernel - [BUG] kernel: rcu: a possible sleep-in-atomic-context bug in srcu_read

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Date:   Mon, 13 Aug 2018 11:04:10 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     dave@...olabs.net, paulmck@...ux.vnet.ibm.com,
        josh@...htriplett.org, rostedt@...dmis.org,
        mathieu.desnoyers@...icios.com, jiangshanlai@...il.com
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: [BUG] kernel: rcu: a possible sleep-in-atomic-context bug in
 srcu_read_delay()

The kernel may sleep with holding a spinlock.

The function call paths (from bottom to top) in Linux-4.16 are:

[FUNC] schedule_timeout_interruptible
kernel/rcu/rcutorture.c, 523: schedule_timeout_interruptible in 
srcu_read_delay
kernel/rcu/rcutorture.c, 1105: [FUNC_PTR]srcu_read_delay in 
rcu_torture_timer
kernel/rcu/rcutorture.c, 1104: spin_lock in rcu_torture_timer

Note that [FUNC_PTR] means a function pointer call is used.

I do not find a good way to fix, so I only report.
This is found by my static analysis tool (DSAC).


Thanks,
Jia-Ju Bai