queue-4.4/arm-8839-1-kprobe-make-patch_lock-a-raw_spinlock_t.patch

   1 From 7aea42a7935dd29e1fc538a36104c6247472cd6a Mon Sep 17 00:00:00 2001
   2 From: Yang Shi <yang.shi@linaro.org>
   3 Date: Wed, 13 Feb 2019 17:14:23 +0100
   4 Subject: ARM: 8839/1: kprobe: make patch_lock a raw_spinlock_t
   5
   6 [ Upstream commit 143c2a89e0e5fda6c6fd08d7bc1126438c19ae90 ]
   7
   8 When running kprobe on -rt kernel, the below bug is caught:
   9
  10 |BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:931
  11 |in_atomic(): 1, irqs_disabled(): 128, pid: 14, name: migration/0
  12 |Preemption disabled at:[<802f2b98>] cpu_stopper_thread+0xc0/0x140
  13 |CPU: 0 PID: 14 Comm: migration/0 Tainted: G O 4.8.3-rt2 #1
  14 |Hardware name: Freescale LS1021A
  15 |[<8025a43c>] (___might_sleep)
  16 |[<80b5b324>] (rt_spin_lock)
  17 |[<80b5c31c>] (__patch_text_real)
  18 |[<80b5c3ac>] (patch_text_stop_machine)
  19 |[<802f2920>] (multi_cpu_stop)
  20
  21 Since patch_text_stop_machine() is called in stop_machine() which
  22 disables IRQ, sleepable lock should be not used in this atomic context,
  23  so replace patch_lock to raw lock.
  24
  25 Signed-off-by: Yang Shi <yang.shi@linaro.org>
  26 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
  27 Reviewed-by: Arnd Bergmann <arnd@arndb.de>
  28 Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
  29 Signed-off-by: Sasha Levin <sashal@kernel.org>
  30 ---
  31  arch/arm/kernel/patch.c | 6 +++---
  32  1 file changed, 3 insertions(+), 3 deletions(-)
  33
  34 diff --git a/arch/arm/kernel/patch.c b/arch/arm/kernel/patch.c
  35 index 69bda1a5707e..1f665acaa6a9 100644
  36 --- a/arch/arm/kernel/patch.c
  37 +++ b/arch/arm/kernel/patch.c
  38 @@ -15,7 +15,7 @@ struct patch {
  39         unsigned int insn;
  40  };
  41
  42 -static DEFINE_SPINLOCK(patch_lock);
  43 +static DEFINE_RAW_SPINLOCK(patch_lock);
  44
  45  static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags)
  46         __acquires(&patch_lock)
  47 @@ -32,7 +32,7 @@ static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags)
  48                 return addr;
  49
  50         if (flags)
  51 -               spin_lock_irqsave(&patch_lock, *flags);
  52 +               raw_spin_lock_irqsave(&patch_lock, *flags);
  53         else
  54                 __acquire(&patch_lock);
  55
  56 @@ -47,7 +47,7 @@ static void __kprobes patch_unmap(int fixmap, unsigned long *flags)
  57         clear_fixmap(fixmap);
  58
  59         if (flags)
  60 -               spin_unlock_irqrestore(&patch_lock, *flags);
  61 +               raw_spin_unlock_irqrestore(&patch_lock, *flags);
  62         else
  63                 __release(&patch_lock);
  64  }
  65 --
  66 2.19.1
  67