Hi,
In linux-next as of today (0824), all h8300 builds fail for me with an internal
compiler error.
Building h8300:allnoconfig ... failed
--------------
Error log:
In file included from include/linux/rcupdate.h:429:0,
from include/linux/rcusync.h:5,
from kernel/rcu/sync.c:1:
include/linux/rcutiny.h: In function ‘rcu_barrier_sched’:
include/linux/rcutiny.h:55:20: internal compiler error: Segmentation fault
static inline void rcu_barrier_sched(void)
^
I tried both gcc 5.1 and 5.2, built with the patch set available to me.
Is there a more recent compiler / patch set available that might fix the problem ?
Thanks,
Guenter
On Tue, 25 Aug 2015 03:34:20 +0900,
Guenter Roeck wrote:
>
> Hi,
>
> In linux-next as of today (0824), all h8300 builds fail for me with an internal
> compiler error.
>
> Building h8300:allnoconfig ... failed
> --------------
> Error log:
>
> In file included from include/linux/rcupdate.h:429:0,
> from include/linux/rcusync.h:5,
> from kernel/rcu/sync.c:1:
> include/linux/rcutiny.h: In function ?rcu_barrier_sched?:
> include/linux/rcutiny.h:55:20: internal compiler error: Segmentation fault
> static inline void rcu_barrier_sched(void)
> ^
>
> I tried both gcc 5.1 and 5.2, built with the patch set available to me.
>
> Is there a more recent compiler / patch set available that might fix the problem ?
>
No.
I tried gcc 6.0. It got same error.
It looks optimization problem on h8300 target.
I will investigate it.
> Thanks,
> Guenter
--
Yoshinori Sato
<[email protected]>
On Tue, 2015-08-25 at 14:56 +0900, Yoshinori Sato wrote:
> On Tue, 25 Aug 2015 03:34:20 +0900,
> Guenter Roeck wrote:
> >
> > Hi,
> >
> > In linux-next as of today (0824), all h8300 builds fail for me with an
> > internal
> > compiler error.
> >
> > Building h8300:allnoconfig ... failed
> > --------------
> > Error log:
> >
> > In file included from include/linux/rcupdate.h:429:0,
> > from include/linux/rcusync.h:5,
> > from kernel/rcu/sync.c:1:
> > include/linux/rcutiny.h: In function ‘rcu_barrier_sched’:
> > include/linux/rcutiny.h:55:20: internal compiler error: Segmentation
> > fault
> > static inline void rcu_barrier_sched(void)
> > ^
> >
> > I tried both gcc 5.1 and 5.2, built with the patch set available to me.
> >
> > Is there a more recent compiler / patch set available that might fix
> > the problem ?
> >
>
> No.
> I tried gcc 6.0. It got same error.
> It looks optimization problem on h8300 target.
> I will investigate it.
I get the same ICE with c6x gcc 5.1
> > Thanks,
> > Guenter
>
Hi Mark,
On 08/25/2015 07:27 AM, Mark Salter wrote:
> On Tue, 2015-08-25 at 14:56 +0900, Yoshinori Sato wrote:
>> On Tue, 25 Aug 2015 03:34:20 +0900,
>> Guenter Roeck wrote:
>>>
>>> Hi,
>>>
>>> In linux-next as of today (0824), all h8300 builds fail for me with an
>>> internal
>>> compiler error.
>>>
>>> Building h8300:allnoconfig ... failed
>>> --------------
>>> Error log:
>>>
>>> In file included from include/linux/rcupdate.h:429:0,
>>> from include/linux/rcusync.h:5,
>>> from kernel/rcu/sync.c:1:
>>> include/linux/rcutiny.h: In function ‘rcu_barrier_sched’:
>>> include/linux/rcutiny.h:55:20: internal compiler error: Segmentation
>>> fault
>>> static inline void rcu_barrier_sched(void)
>>> ^
>>>
>>> I tried both gcc 5.1 and 5.2, built with the patch set available to me.
>>>
>>> Is there a more recent compiler / patch set available that might fix
>>> the problem ?
>>>
>>
>> No.
>> I tried gcc 6.0. It got same error.
>> It looks optimization problem on h8300 target.
>> I will investigate it.
>
> I get the same ICE with c6x gcc 5.1
>
Interesting. h8300 was the only gcc 5+ compiler I had used so far.
Just for fun, I built an alpha toolchain with gcc 5.1. Same problem there.
So it looks like it isn't a h8300 problem after all, it is a gcc problem.
Updated subject line, and copied rcu maintainers.
Guenter
On 08/25, Guenter Roeck wrote:
>
> Hi Mark,
>
> On 08/25/2015 07:27 AM, Mark Salter wrote:
>> On Tue, 2015-08-25 at 14:56 +0900, Yoshinori Sato wrote:
>>> On Tue, 25 Aug 2015 03:34:20 +0900,
>>> Guenter Roeck wrote:
>>>>
>>>> Hi,
>>>>
>>>> In linux-next as of today (0824), all h8300 builds fail for me with an
>>>> internal
>>>> compiler error.
>>>>
>>>> Building h8300:allnoconfig ... failed
>>>> --------------
>>>> Error log:
>>>>
>>>> In file included from include/linux/rcupdate.h:429:0,
>>>> from include/linux/rcusync.h:5,
>>>> from kernel/rcu/sync.c:1:
>>>> include/linux/rcutiny.h: In function ‘rcu_barrier_sched’:
>>>> include/linux/rcutiny.h:55:20: internal compiler error: Segmentation
>>>> fault
>>>> static inline void rcu_barrier_sched(void)
>>>> ^
>>>>
>>>> I tried both gcc 5.1 and 5.2, built with the patch set available to me.
>>>>
>>>> Is there a more recent compiler / patch set available that might fix
>>>> the problem ?
>>>>
>>>
>>> No.
>>> I tried gcc 6.0. It got same error.
>>> It looks optimization problem on h8300 target.
>>> I will investigate it.
>>
>> I get the same ICE with c6x gcc 5.1
>>
>
> Interesting. h8300 was the only gcc 5+ compiler I had used so far.
> Just for fun, I built an alpha toolchain with gcc 5.1. Same problem there.
> So it looks like it isn't a h8300 problem after all, it is a gcc problem.
>
> Updated subject line, and copied rcu maintainers.
Damn. This was caused by my patch, I need to react, and I do not know
what to say ;)
OK, this is gcc bug. But we probably need the workaround, and I don't
have a h8300 machine so I can't test the fix.
Could you please try to compile kernel/rcu/sync.o with the patch below?
Just to know how "stable" this bug is. I expect the compilation should
fail again, rcutiny.h:rcu_barrier() is "inline" too.
Oleg.
--- a/kernel/rcu/sync.c
+++ b/kernel/rcu/sync.c
@@ -24,7 +24,6 @@ static const struct {
[RCU_SCHED_SYNC] = {
.sync = synchronize_sched,
.call = call_rcu_sched,
- .wait = rcu_barrier_sched,
__INIT_HELD(rcu_read_lock_sched_held)
},
[RCU_BH_SYNC] = {
On 08/25, Oleg Nesterov wrote:
>
> OK, this is gcc bug. But we probably need the workaround, and I don't
> have a h8300 machine so I can't test the fix.
>
> Could you please try to compile kernel/rcu/sync.o with the patch below?
> Just to know how "stable" this bug is. I expect the compilation should
> fail again, rcutiny.h:rcu_barrier() is "inline" too.
Wait, I reproduced the same problem on x86. Thanks.
Oleg.
On Wed, 26 Aug 2015 00:03:35 +0900,
Guenter Roeck wrote:
>
> Hi Mark,
>
> On 08/25/2015 07:27 AM, Mark Salter wrote:
> > On Tue, 2015-08-25 at 14:56 +0900, Yoshinori Sato wrote:
> >> On Tue, 25 Aug 2015 03:34:20 +0900,
> >> Guenter Roeck wrote:
> >>>
> >>> Hi,
> >>>
> >>> In linux-next as of today (0824), all h8300 builds fail for me with an
> >>> internal
> >>> compiler error.
> >>>
> >>> Building h8300:allnoconfig ... failed
> >>> --------------
> >>> Error log:
> >>>
> >>> In file included from include/linux/rcupdate.h:429:0,
> >>> from include/linux/rcusync.h:5,
> >>> from kernel/rcu/sync.c:1:
> >>> include/linux/rcutiny.h: In function ?rcu_barrier_sched?:
> >>> include/linux/rcutiny.h:55:20: internal compiler error: Segmentation
> >>> fault
> >>> static inline void rcu_barrier_sched(void)
> >>> ^
> >>>
> >>> I tried both gcc 5.1 and 5.2, built with the patch set available to me.
> >>>
> >>> Is there a more recent compiler / patch set available that might fix
> >>> the problem ?
> >>>
> >>
> >> No.
> >> I tried gcc 6.0. It got same error.
> >> It looks optimization problem on h8300 target.
> >> I will investigate it.
> >
> > I get the same ICE with c6x gcc 5.1
> >
>
> Interesting. h8300 was the only gcc 5+ compiler I had used so far.
> Just for fun, I built an alpha toolchain with gcc 5.1. Same problem there.
> So it looks like it isn't a h8300 problem after all, it is a gcc problem.
>
> Updated subject line, and copied rcu maintainers.
>
> Guenter
>
Yes.
gcc bug #67055.
Already fixed in trunk.
--
Yoshinori Sato
<[email protected]>
On 08/26, Yoshinori Sato wrote:
>
> Yes.
> gcc bug #67055.
> Already fixed in trunk.
Yes, thanks a lot.
Paul, it seems that gcc actually dislikes your ec90a194a "rcu:
Create a synchronize_rcu_mult()" commit ;) rcu/sync.c was just
lucky enough to trigger the problem.
I'll try to make the fix today...
Oleg.
On 08/25, Oleg Nesterov wrote:
>
> On 08/26, Yoshinori Sato wrote:
> >
> > Yes.
> > gcc bug #67055.
> > Already fixed in trunk.
>
> Yes, thanks a lot.
>
> Paul, it seems that gcc actually dislikes your ec90a194a "rcu:
> Create a synchronize_rcu_mult()" commit ;) rcu/sync.c was just
> lucky enough to trigger the problem.
>
> I'll try to make the fix today...
Mark, Guenter, any chance you can check if the patch below helps?
It does on x86.
Oleg.
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -230,12 +230,11 @@ void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,
struct rcu_synchronize *rs_array);
#define _wait_rcu_gp(checktiny, ...) \
-do { \
- call_rcu_func_t __crcu_array[] = { __VA_ARGS__ }; \
- const int __n = ARRAY_SIZE(__crcu_array); \
- struct rcu_synchronize __rs_array[__n]; \
- \
- __wait_rcu_gp(checktiny, __n, __crcu_array, __rs_array); \
+do { \
+ call_rcu_func_t __crcu_array[] = { __VA_ARGS__ }; \
+ struct rcu_synchronize __rs_array[ARRAY_SIZE(__crcu_array)]; \
+ __wait_rcu_gp(checktiny, ARRAY_SIZE(__crcu_array), \
+ __crcu_array, __rs_array); \
} while (0)
#define wait_rcu_gp(...) _wait_rcu_gp(false, __VA_ARGS__)
On Tue, 2015-08-25 at 20:02 +0200, Oleg Nesterov wrote:
> On 08/25, Oleg Nesterov wrote:
> >
> > On 08/26, Yoshinori Sato wrote:
> > >
> > > Yes.
> > > gcc bug #67055.
> > > Already fixed in trunk.
> >
> > Yes, thanks a lot.
> >
> > Paul, it seems that gcc actually dislikes your ec90a194a "rcu:
> > Create a synchronize_rcu_mult()" commit ;) rcu/sync.c was just
> > lucky enough to trigger the problem.
> >
> > I'll try to make the fix today...
>
> Mark, Guenter, any chance you can check if the patch below helps?
> It does on x86.
Works for c6x.
>
> Oleg.
>
> --- a/include/linux/rcupdate.h
> +++ b/include/linux/rcupdate.h
> @@ -230,12 +230,11 @@ void __wait_rcu_gp(bool checktiny, int n,
> call_rcu_func_t *crcu_array,
> struct rcu_synchronize *rs_array);
>
> #define _wait_rcu_gp(checktiny, ...) \
> -do { \
> - call_rcu_func_t __crcu_array[] = { __VA_ARGS__ }; \
> - const int __n = ARRAY_SIZE(__crcu_array); \
> - struct rcu_synchronize __rs_array[__n]; \
> - \
> - __wait_rcu_gp(checktiny, __n, __crcu_array, __rs_array); \
> +do {
> \
> + call_rcu_func_t __crcu_array[] = { __VA_ARGS__ };
> \
> + struct rcu_synchronize __rs_array[ARRAY_SIZE(__crcu_array)];
> \
> + __wait_rcu_gp(checktiny, ARRAY_SIZE(__crcu_array),
> \
> + __crcu_array, __rs_array);
> \
> } while (0)
>
> #define wait_rcu_gp(...) _wait_rcu_gp(false, __VA_ARGS__)
>
The code like
const int n = const-expr;
whatever_t array[n];
in inline function can confuse gcc, see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67055#c13
This leads to
In file included from include/linux/rcupdate.h:429:0,
from include/linux/rcusync.h:5,
from kernel/rcu/sync.c:1:
include/linux/rcutiny.h: In function 'rcu_barrier_sched':
include/linux/rcutiny.h:55:20: internal compiler error: Segmentation
fault
static inline void rcu_barrier_sched(void)
build failure after ec90a194a "rcu: Create a synchronize_rcu_mult()"
and 114b7fd4b "rcu: Create rcu_sync infrastructure" meet each other.
Reported-and-tested-by: Mark Salter <[email protected]>
Reported-by: Guenter Roeck <[email protected]>
Signed-off-by: Oleg Nesterov <[email protected]>
---
include/linux/rcupdate.h | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index ff47651..c353c2b 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -230,12 +230,11 @@ void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,
struct rcu_synchronize *rs_array);
#define _wait_rcu_gp(checktiny, ...) \
-do { \
- call_rcu_func_t __crcu_array[] = { __VA_ARGS__ }; \
- const int __n = ARRAY_SIZE(__crcu_array); \
- struct rcu_synchronize __rs_array[__n]; \
- \
- __wait_rcu_gp(checktiny, __n, __crcu_array, __rs_array); \
+do { \
+ call_rcu_func_t __crcu_array[] = { __VA_ARGS__ }; \
+ struct rcu_synchronize __rs_array[ARRAY_SIZE(__crcu_array)]; \
+ __wait_rcu_gp(checktiny, ARRAY_SIZE(__crcu_array), \
+ __crcu_array, __rs_array); \
} while (0)
#define wait_rcu_gp(...) _wait_rcu_gp(false, __VA_ARGS__)
--
2.4.3
On Tue, Aug 25, 2015 at 08:45:18PM +0200, Oleg Nesterov wrote:
> The code like
>
> const int n = const-expr;
> whatever_t array[n];
>
> in inline function can confuse gcc, see
>
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67055#c13
>
> This leads to
>
> In file included from include/linux/rcupdate.h:429:0,
> from include/linux/rcusync.h:5,
> from kernel/rcu/sync.c:1:
> include/linux/rcutiny.h: In function 'rcu_barrier_sched':
> include/linux/rcutiny.h:55:20: internal compiler error: Segmentation
> fault
> static inline void rcu_barrier_sched(void)
>
> build failure after ec90a194a "rcu: Create a synchronize_rcu_mult()"
> and 114b7fd4b "rcu: Create rcu_sync infrastructure" meet each other.
>
> Reported-and-tested-by: Mark Salter <[email protected]>
> Reported-by: Guenter Roeck <[email protected]>
> Signed-off-by: Oleg Nesterov <[email protected]>
Ouch!!! Queued for testing, in the absence of problems, will push into
the upcoming merge window.
Thank you all for the testing and the fix!
Thanx, Paul
> ---
> include/linux/rcupdate.h | 11 +++++------
> 1 file changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
> index ff47651..c353c2b 100644
> --- a/include/linux/rcupdate.h
> +++ b/include/linux/rcupdate.h
> @@ -230,12 +230,11 @@ void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,
> struct rcu_synchronize *rs_array);
>
> #define _wait_rcu_gp(checktiny, ...) \
> -do { \
> - call_rcu_func_t __crcu_array[] = { __VA_ARGS__ }; \
> - const int __n = ARRAY_SIZE(__crcu_array); \
> - struct rcu_synchronize __rs_array[__n]; \
> - \
> - __wait_rcu_gp(checktiny, __n, __crcu_array, __rs_array); \
> +do { \
> + call_rcu_func_t __crcu_array[] = { __VA_ARGS__ }; \
> + struct rcu_synchronize __rs_array[ARRAY_SIZE(__crcu_array)]; \
> + __wait_rcu_gp(checktiny, ARRAY_SIZE(__crcu_array), \
> + __crcu_array, __rs_array); \
> } while (0)
>
> #define wait_rcu_gp(...) _wait_rcu_gp(false, __VA_ARGS__)
> --
> 2.4.3
>
>
On 08/25, Oleg Nesterov wrote:
>
> The code like
>
> const int n = const-expr;
> whatever_t array[n];
>
> in inline function can confuse gcc, see
>
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67055#c13
>
> This leads to
>
> In file included from include/linux/rcupdate.h:429:0,
> from include/linux/rcusync.h:5,
> from kernel/rcu/sync.c:1:
> include/linux/rcutiny.h: In function 'rcu_barrier_sched':
> include/linux/rcutiny.h:55:20: internal compiler error: Segmentation
> fault
> static inline void rcu_barrier_sched(void)
>
> build failure after ec90a194a "rcu: Create a synchronize_rcu_mult()"
> and 114b7fd4b "rcu: Create rcu_sync infrastructure" meet each other.
and just in case... make make kernel/rcu/rcutorture.o fails the same
way if CONFIG_RCU_TORTURE_TEST && CONFIG_TINY_RCU. So we need a work-
around even before/without rcu_sync.
Oleg.