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authorYadi.hu <yadi.hu@windriver.com>2014-12-10 05:32:09 +0300
committerMinda Chen <minda.chen@starfivetech.com>2023-11-06 14:24:52 +0300
commitf39aa40a92b3cc6749463638c68503ff04bf8022 (patch)
tree8ef7b3d93ab3a0f168fb7f2c5586eb3c05c9b343
parent7bf110becd54c507a4d4534c8ee6e85564f15211 (diff)
downloadlinux-f39aa40a92b3cc6749463638c68503ff04bf8022.tar.xz
ARM: enable irq in translation/section permission fault handlers
Probably happens on all ARM, with CONFIG_PREEMPT_RT 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> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--arch/arm/mm/fault.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index efa402025031..59487ee9fd61 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -400,6 +400,9 @@ 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;
@@ -470,6 +473,9 @@ 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;
}