forked from rrcarlosr/Jetpack
95 lines
3.4 KiB
Diff
95 lines
3.4 KiB
Diff
|
From 75b59b568a3a47f80113b5359bc5211d0c7a052a Mon Sep 17 00:00:00 2001
|
||
|
|
From: "Yadi.hu" <yadi.hu@windriver.com>
|
||
|
|
Date: Wed, 10 Dec 2014 10:32:09 +0800
|
||
|
|
Subject: [PATCH 255/352] ARM: enable irq in translation/section permission
|
||
|
|
fault handlers
|
||
|
|
MIME-Version: 1.0
|
||
|
|
Content-Type: text/plain; charset=UTF-8
|
||
|
|
Content-Transfer-Encoding: 8bit
|
||
|
|
|
||
|
|
Probably happens on all ARM, with
|
||
|
|
CONFIG_PREEMPT_RT_FULL
|
||
|
|
CONFIG_DEBUG_ATOMIC_SLEEP
|
||
|
|
|
||
|
|
This simple program....
|
||
|
|
|
||
|
|
int main() {
|
||
|
|
*((char*)0xc0001000) = 0;
|
||
|
|
};
|
||
|
|
|
||
|
|
[ 512.742724] BUG: sleeping function called from invalid context at kernel/rtmutex.c:658
|
||
|
|
[ 512.743000] in_atomic(): 0, irqs_disabled(): 128, pid: 994, name: a
|
||
|
|
[ 512.743217] INFO: lockdep is turned off.
|
||
|
|
[ 512.743360] irq event stamp: 0
|
||
|
|
[ 512.743482] hardirqs last enabled at (0): [< (null)>] (null)
|
||
|
|
[ 512.743714] hardirqs last disabled at (0): [<c0426370>] copy_process+0x3b0/0x11c0
|
||
|
|
[ 512.744013] softirqs last enabled at (0): [<c0426370>] copy_process+0x3b0/0x11c0
|
||
|
|
[ 512.744303] softirqs last disabled at (0): [< (null)>] (null)
|
||
|
|
[ 512.744631] [<c041872c>] (unwind_backtrace+0x0/0x104)
|
||
|
|
[ 512.745001] [<c09af0c4>] (dump_stack+0x20/0x24)
|
||
|
|
[ 512.745355] [<c0462490>] (__might_sleep+0x1dc/0x1e0)
|
||
|
|
[ 512.745717] [<c09b6770>] (rt_spin_lock+0x34/0x6c)
|
||
|
|
[ 512.746073] [<c0441bf0>] (do_force_sig_info+0x34/0xf0)
|
||
|
|
[ 512.746457] [<c0442668>] (force_sig_info+0x18/0x1c)
|
||
|
|
[ 512.746829] [<c041d880>] (__do_user_fault+0x9c/0xd8)
|
||
|
|
[ 512.747185] [<c041d938>] (do_bad_area+0x7c/0x94)
|
||
|
|
[ 512.747536] [<c041d990>] (do_sect_fault+0x40/0x48)
|
||
|
|
[ 512.747898] [<c040841c>] (do_DataAbort+0x40/0xa0)
|
||
|
|
[ 512.748181] Exception stack(0xecaa1fb0 to 0xecaa1ff8)
|
||
|
|
|
||
|
|
Oxc0000000 belongs to kernel address space, user task can not be
|
||
|
|
allowed to access it. For above condition, correct result is that
|
||
|
|
test case should receive a “segment fault” and exits but not stacks.
|
||
|
|
|
||
|
|
the root cause is commit 02fe2845d6a8 ("avoid enabling interrupts in
|
||
|
|
prefetch/data abort handlers"),it deletes irq enable block in Data
|
||
|
|
abort assemble code and move them into page/breakpiont/alignment fault
|
||
|
|
handlers instead. But author does not enable irq in translation/section
|
||
|
|
permission fault handlers. ARM disables irq when it enters exception/
|
||
|
|
interrupt mode, if kernel doesn't enable irq, it would be still disabled
|
||
|
|
during translation/section permission fault.
|
||
|
|
|
||
|
|
We see the above splat because do_force_sig_info is still called with
|
||
|
|
IRQs off, and that code eventually does a:
|
||
|
|
|
||
|
|
spin_lock_irqsave(&t->sighand->siglock, flags);
|
||
|
|
|
||
|
|
As this is architecture independent code, and we've not seen any other
|
||
|
|
need for other arch to have the siglock converted to raw lock, we can
|
||
|
|
conclude that we should enable irq for ARM translation/section
|
||
|
|
permission exception.
|
||
|
|
|
||
|
|
Signed-off-by: Yadi.hu <yadi.hu@windriver.com>
|
||
|
|
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
|
||
|
|
---
|
||
|
|
arch/arm/mm/fault.c | 6 ++++++
|
||
|
|
1 file changed, 6 insertions(+)
|
||
|
|
|
||
|
|
diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
|
||
|
|
index d6c9dee..4539678 100644
|
||
|
|
--- a/arch/arm/mm/fault.c
|
||
|
|
+++ b/arch/arm/mm/fault.c
|
||
|
|
@@ -436,6 +436,9 @@ do_translation_fault(unsigned long addr, unsigned int fsr,
|
||
|
|
if (addr < TASK_SIZE)
|
||
|
|
return do_page_fault(addr, fsr, regs);
|
||
|
|
|
||
|
|
+ if (interrupts_enabled(regs))
|
||
|
|
+ local_irq_enable();
|
||
|
|
+
|
||
|
|
if (user_mode(regs))
|
||
|
|
goto bad_area;
|
||
|
|
|
||
|
|
@@ -503,6 +506,9 @@ do_translation_fault(unsigned long addr, unsigned int fsr,
|
||
|
|
static int
|
||
|
|
do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
|
||
|
|
{
|
||
|
|
+ if (interrupts_enabled(regs))
|
||
|
|
+ local_irq_enable();
|
||
|
|
+
|
||
|
|
do_bad_area(addr, fsr, regs);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
--
|
||
|
|
2.7.4
|
||
|
|
|