ARM: 8839/1: kprobe: make patch_lock a raw_spinlock_t

Yang Shi · Russell King · commit 143c2a89e0e5 · 2019-02-26T11:24:50.000Z
When running kprobe on -rt kernel, the below bug is caught:

|BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:931
|in_atomic(): 1, irqs_disabled(): 128, pid: 14, name: migration/0
|Preemption disabled at:[&lt;802f2b98&gt;] cpu_stopper_thread+0xc0/0x140
|CPU: 0 PID: 14 Comm: migration/0 Tainted: G O 4.8.3-rt2 #1
|Hardware name: Freescale LS1021A
|[&lt;8025a43c&gt;] (___might_sleep)
|[&lt;80b5b324&gt;] (rt_spin_lock)
|[&lt;80b5c31c&gt;] (__patch_text_real)
|[&lt;80b5c3ac&gt;] (patch_text_stop_machine)
|[&lt;802f2920&gt;] (multi_cpu_stop)

Since patch_text_stop_machine() is called in stop_machine() which
disables IRQ, sleepable lock should be not used in this atomic context,
 so replace patch_lock to raw lock.

Signed-off-by: Yang Shi &lt;yang.shi@linaro.org&gt;
Signed-off-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Reviewed-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Signed-off-by: Russell King &lt;rmk+kernel@armlinux.org.uk&gt;
diff --git a/arch/arm/kernel/patch.c b/arch/arm/kernel/patch.c
@@ -16,7 +16,7 @@ struct patch {
 	unsigned int insn;
 };
 
-static DEFINE_SPINLOCK(patch_lock);
+static DEFINE_RAW_SPINLOCK(patch_lock);
 
 static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags)
 	__acquires(&patch_lock)
@@ -33,7 +33,7 @@ static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags)
 		return addr;
 
 	if (flags)
-		spin_lock_irqsave(&patch_lock, *flags);
+		raw_spin_lock_irqsave(&patch_lock, *flags);
 	else
 		__acquire(&patch_lock);
 
@@ -48,7 +48,7 @@ static void __kprobes patch_unmap(int fixmap, unsigned long *flags)
 	clear_fixmap(fixmap);
 
 	if (flags)
-		spin_unlock_irqrestore(&patch_lock, *flags);
+		raw_spin_unlock_irqrestore(&patch_lock, *flags);
 	else
 		__release(&patch_lock);
 }
