Re: [PATCH, -v3] compiler/gcc4: Add quirk for 'asm goto'miscompilation bug

From: Fengguang Wu
Date: Fri Oct 11 2013 - 00:36:23 EST

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On Thu, Oct 10, 2013 at 05:12:19PM +0200, Ingo Molnar wrote:
>
> * Jakub Jelinek <jakub@xxxxxxxxxx> wrote:
>
> > On Thu, Oct 10, 2013 at 07:04:18AM -0700, Richard Henderson wrote:
> > > On 10/10/2013 01:31 AM, Jakub Jelinek wrote:
> > > > Also, for the bitops patch, you probably want an asm_volatile_goto variant.
> > >
> > > Why? Asm without output (which asm goto must be) are automatically volatile.
> >
> > You're right.
>
> Indeed. Something like the updated version below?
>
> [ I kept the asm_volatile_goto() naming to make sure the implicit volatile
> is visible. ]

Ingo, I applied this patch (as commit c015a7f0b746) on top of
tip/sched/core

3354781a2184 "sched/numa: Reflow task_numa_group() to avoid a compiler warning"

The below results show that it does fixed the many oops:

/kernel/i386-randconfig-i005-1008/c015a7f0b746d0a7e18b82876bd2b693722479d2

+--------------------------------------------------------------+--------------+--------------+
| | 3354781a2184 | c015a7f0b746 |
+--------------------------------------------------------------+--------------+--------------+
| WARNING:CPU:PID:at_fs/sysfs/dir.c:sysfs_add_one() | 9 | |
| WARNING:CPU:PID:at_lib/kobject.c:kobject_add_internal() | 9 | |
| WARNING:CPU:PID:at_drivers/base/driver.c:driver_unregister() | 9 | |
| WARNING:CPU:PID:at_lib/list_debug.c:__list_add() | 9 | |
| kernel_BUG_at_kernel/timer.c | 9 | |
| invalid_opcode:PREEMPT_SMP | 9 | |
| Kernel_panic-not_syncing:Fatal_exception_in_interrupt | 9 | |
| good_boots | 0 | 9 |
+--------------------------------------------------------------+--------------+--------------+

/kernel/i386-randconfig-r4-1009/c015a7f0b746d0a7e18b82876bd2b693722479d2

+--------------------------------------------------------------+--------------+--------------+
| | 3354781a2184 | c015a7f0b746 |
+--------------------------------------------------------------+--------------+--------------+
| BUG:kernel_early_hang_without_any_printk_output | 2 | 3 |
| WARNING:CPU:PID:at_fs/sysfs/dir.c:sysfs_add_one() | 7 | |
| WARNING:CPU:PID:at_lib/kobject.c:kobject_add_internal() | 7 | |
| WARNING:CPU:PID:at_drivers/base/driver.c:driver_unregister() | 7 | |
| WARNING:CPU:PID:at_lib/debugobjects.c:debug_print_object() | 7 | |
| INFO:trying_to_register_non-static_key | 7 | |
| kernel_BUG_at_kernel/timer.c | 7 | |
| invalid_opcode:SMP | 7 | |
| Kernel_panic-not_syncing:Fatal_exception_in_interrupt | 7 | |
| good_boots | 0 | 6 |
+--------------------------------------------------------------+--------------+--------------+

/kernel/i386-randconfig-r8-1005/c015a7f0b746d0a7e18b82876bd2b693722479d2

+---------------------------------------------------------------+--------------+--------------+
| | 3354781a2184 | c015a7f0b746 |
+---------------------------------------------------------------+--------------+--------------+
| BUG:unable_to_handle_kernel_NULL_pointer_dereference_at | 1 | |
| Oops:DEBUG_PAGEALLOC | 9 | |
| kernel_BUG_at_kernel/cred.c | 1 | |
| invalid_opcode:DEBUG_PAGEALLOC | 1 | |
| Kernel_panic-not_syncing:CRED:put_cred_rcu()sees_with_usage | 4 | |
| BUG:unable_to_handle_kernel_paging_request_at | 3 | |
| BUG:unable_to_handle_kernel_NULL_pointer_dereference_at(null) | 5 | |
| good_boots | 0 | 9 |
+---------------------------------------------------------------+--------------+--------------+

However it seems that it leads to or increases the chances of early
boot hang:

/kernel/x86_64-randconfig-a1-1009/c015a7f0b746d0a7e18b82876bd2b693722479d2

+-------------------------------------------------+--------------+--------------+
| | 3354781a2184 | c015a7f0b746 |
+-------------------------------------------------+--------------+--------------+
| good_boots | 9 | 8 |
| BUG:kernel_early_hang_without_any_printk_output | 0 | 1 |
+-------------------------------------------------+--------------+--------------+

/kernel/x86_64-randconfig-a5-1009/c015a7f0b746d0a7e18b82876bd2b693722479d2

+-------------------------------------------------+--------------+--------------+
| | 3354781a2184 | c015a7f0b746 |
+-------------------------------------------------+--------------+--------------+
| good_boots | 9 | 8 |
| BUG:kernel_early_hang_without_any_printk_output | 0 | 1 |
+-------------------------------------------------+--------------+--------------+

/kernel/i386-randconfig-r1-1009/c015a7f0b746d0a7e18b82876bd2b693722479d2

+-------------------------------------------------+--------------+--------------+
| | 3354781a2184 | c015a7f0b746 |
+-------------------------------------------------+--------------+--------------+
| BUG:kernel_early_hang_without_any_printk_output | 9 | 9 |
+-------------------------------------------------+--------------+--------------+

/kernel/i386-randconfig-r7-1009/c015a7f0b746d0a7e18b82876bd2b693722479d2

+--------------------------------------------------+--------------+--------------+
| | 3354781a2184 | c015a7f0b746 |
+--------------------------------------------------+--------------+--------------+
| BUG:soft_lockup-CPU_stuck_for_s | 1 | |
| INFO:task_blocked_for_more_than_seconds | 8 | 8 |
| Kernel_panic-not_syncing:hung_task:blocked_tasks | 8 | 8 |
| BUG:kernel_early_hang_without_any_printk_output | 0 | 1 |
+--------------------------------------------------+--------------+--------------+

/kernel/i386-randconfig-r5-1009/c015a7f0b746d0a7e18b82876bd2b693722479d2

+-------------------------------------------------+--------------+--------------+
| | 3354781a2184 | c015a7f0b746 |
+-------------------------------------------------+--------------+--------------+
| BUG:kernel_early_hang_without_any_printk_output | 9 | 9 |
+-------------------------------------------------+--------------+--------------+

/kernel/i386-randconfig-i008-1008/c015a7f0b746d0a7e18b82876bd2b693722479d2

+-------------------------------------------------+--------------+--------------+
| | 3354781a2184 | c015a7f0b746 |
+-------------------------------------------------+--------------+--------------+
| BUG:kernel_early_hang_without_any_printk_output | 9 | 9 |
+-------------------------------------------------+--------------+--------------+

/kernel/i386-randconfig-i006-1008/c015a7f0b746d0a7e18b82876bd2b693722479d2

+-------------------------------------------------+--------------+--------------+
| | 3354781a2184 | c015a7f0b746 |
+-------------------------------------------------+--------------+--------------+
| good_boots | 9 | 7 |
| BUG:kernel_early_hang_without_any_printk_output | 0 | 2 |
+-------------------------------------------------+--------------+--------------+

Thanks,
Fengguang
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Next message: Wei Yongjun: "[PATCH] Staging: crystalhd: use vfree() instead of kfree()"
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In reply to: Ingo Molnar: "Re: [PATCH, -v3] compiler/gcc4: Add quirk for 'asm goto'miscompilation bug"
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