From: Thomas Gleixner <tglx@linutronix.de>
To: Z qiang <qiang.zhang1211@gmail.com>, paulmck@kernel.org
Cc: syzbot <syzbot+dce04ed6d1438ad69656@syzkaller.appspotmail.com>,
linux-kernel@vger.kernel.org, peterz@infradead.org,
syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [kernel?] WARNING: suspicious RCU usage in __do_softirq
Date: Mon, 22 Apr 2024 23:15:28 +0200 [thread overview]
Message-ID: <87o7a1umj3.ffs@tglx> (raw)
In-Reply-To: <CALm+0cXGBPWxiNOkAoQG4hdnKCeVVR-APbfBPk9OGeU2RW+bKA@mail.gmail.com>
On Fri, Apr 19 2024 at 13:50, Z qiang wrote:
>> On Thu, Apr 18, 2024 at 05:49:38PM +0800, Z qiang wrote:
> static __init int spawn_ksoftirqd(void)
> {
> + int cpu;
> +
> + for_each_possible_cpu(cpu)
> + per_cpu(ksoftirqd_work, cpu) = false;
First of all that initialization is pointless, but why making all of
this complex as hell?
Thanks,
tglx
---
diff --git a/kernel/softirq.c b/kernel/softirq.c
index b315b21fb28c..e991d735be0d 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -508,7 +508,7 @@ static inline bool lockdep_softirq_start(void) { return false; }
static inline void lockdep_softirq_end(bool in_hardirq) { }
#endif
-asmlinkage __visible void __softirq_entry __do_softirq(void)
+static void handle_softirqs(bool kirqd)
{
unsigned long end = jiffies + MAX_SOFTIRQ_TIME;
unsigned long old_flags = current->flags;
@@ -563,8 +563,7 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
pending >>= softirq_bit;
}
- if (!IS_ENABLED(CONFIG_PREEMPT_RT) &&
- __this_cpu_read(ksoftirqd) == current)
+ if (!IS_ENABLED(CONFIG_PREEMPT_RT) && kirqd)
rcu_softirq_qs();
local_irq_disable();
@@ -584,6 +583,11 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
current_restore_flags(old_flags, PF_MEMALLOC);
}
+asmlinkage __visible void __softirq_entry __do_softirq(void)
+{
+ handle_softirqs(false);
+}
+
/**
* irq_enter_rcu - Enter an interrupt context with RCU watching
*/
@@ -921,7 +925,7 @@ static void run_ksoftirqd(unsigned int cpu)
* We can safely run softirq on inline stack, as we are not deep
* in the task stack here.
*/
- __do_softirq();
+ handle_softirqs(true);
ksoftirqd_run_end();
cond_resched();
return;
next prev parent reply other threads:[~2024-04-22 21:15 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-02 18:05 [syzbot] [kernel?] WARNING: suspicious RCU usage in __do_softirq syzbot
2024-04-16 7:05 ` syzbot
2024-04-16 8:10 ` Z qiang
2024-04-16 8:44 ` Z qiang
2024-04-17 1:13 ` Paul E. McKenney
2024-04-17 2:25 ` Z qiang
2024-04-17 22:39 ` Paul E. McKenney
2024-04-18 9:49 ` Z qiang
2024-04-18 22:49 ` Paul E. McKenney
2024-04-19 5:50 ` Z qiang
2024-04-19 6:11 ` Z qiang
2024-04-19 7:12 ` Paul E. McKenney
2024-04-19 7:29 ` Z qiang
2024-04-22 21:15 ` Thomas Gleixner [this message]
2024-04-23 2:20 ` Z qiang
2024-04-23 22:28 ` Paul E. McKenney
2024-04-26 2:09 ` Z qiang
2024-04-26 17:23 ` Thomas Gleixner
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