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* Can not get output of command line on SH
@ 2012-08-31  7:32 Nobuhiro Iwamatsu
  2012-08-31 13:10 ` Al Viro
  0 siblings, 1 reply; 4+ messages in thread
From: Nobuhiro Iwamatsu @ 2012-08-31  7:32 UTC (permalink / raw)
  To: Al Viro; +Cc: Paul Mundt, Linux Kernel Mailing List

Hi, Al.

I can not get output of command line on SH in latest linux kernel.
I bisected, I confirmed that this problem occurred by  following commit.

-----
commit 4a9d4b024a3102fc083c925c242d98ac27b1c5f6
Author: Al Viro <viro@zeniv.linux.org.uk>
Date:   Sun Jun 24 09:56:45 2012 +0400

    switch fput to task_work_add

    ... and schedule_work() for interrupt/kernel_thread callers
    (and yes, now it *is* OK to call from interrupt).

    We are guaranteed that __fput() will be done before we return
    to userland (or exit).  Note that for fput() from a kernel
    thread we get an async behaviour; it's almost always OK, but
    sometimes you might need to have __fput() completed before
    you do anything else.  There are two mechanisms for that -
    a general barrier (flush_delayed_fput()) and explicit
    __fput_sync().  Both should be used with care (as was the
    case for fput() from kernel threads all along).  See comments
    in fs/file_table.c for details.

    Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-----

For example ,when I input 'ls', nothing is displayed.
However, it is outputted when 'Ctrl+C' is inputted.
I checked other CPUs, it is only SH that this problem occurs.

Paul, do you think about this?

Best regards,
  Nobuhiro

-- 
Nobuhiro Iwamatsu

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Can not get output of command line on SH
  2012-08-31  7:32 Can not get output of command line on SH Nobuhiro Iwamatsu
@ 2012-08-31 13:10 ` Al Viro
  2012-09-03  2:56   ` Nobuhiro Iwamatsu
  0 siblings, 1 reply; 4+ messages in thread
From: Al Viro @ 2012-08-31 13:10 UTC (permalink / raw)
  To: Nobuhiro Iwamatsu; +Cc: Paul Mundt, Linux Kernel Mailing List

On Fri, Aug 31, 2012 at 04:32:45PM +0900, Nobuhiro Iwamatsu wrote:
> Hi, Al.
> 
> I can not get output of command line on SH in latest linux kernel.
> I bisected, I confirmed that this problem occurred by  following commit.
> 
> -----
> commit 4a9d4b024a3102fc083c925c242d98ac27b1c5f6
> Author: Al Viro <viro@zeniv.linux.org.uk>
> Date:   Sun Jun 24 09:56:45 2012 +0400
> 
>     switch fput to task_work_add

> For example ,when I input 'ls', nothing is displayed.
> However, it is outputted when 'Ctrl+C' is inputted.
> I checked other CPUs, it is only SH that this problem occurs.
> 
> Paul, do you think about this?

Smells like broken TIF_NOTIFY_RESUME hookup on sh...  Arrrgh.  Looks like
while it is in the relevant masks *and* checked in do_notify_resume() both
on 32bit and 64bit variants since commit ab99c733ae73cce31f2a2434f7099564e5a73d95
Author: Paul Mundt <lethal@linux-sh.org>
Date:   Wed Jul 30 19:55:30 2008 +0900

    sh: Make syscall tracer use tracehook notifiers, add TIF_NOTIFY_RESUME.

they are actually *not* reached without simulataneous SIGPENDING, since the
actual glue in the callers had not been updated back then and still checks
for _TIF_SIGPENDING alone when deciding whether to hit do_notify_resume()
or not.  Looks like the following ought to fix that:

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
diff --git a/arch/sh/kernel/cpu/sh5/entry.S b/arch/sh/kernel/cpu/sh5/entry.S
index b7cf6a5..7e605b9 100644
--- a/arch/sh/kernel/cpu/sh5/entry.S
+++ b/arch/sh/kernel/cpu/sh5/entry.S
@@ -933,7 +933,7 @@ ret_with_reschedule:
 
 	pta	restore_all, tr1
 
-	movi	_TIF_SIGPENDING, r8
+	movi	(_TIF_SIGPENDING|_TIF_NOTIFY_RESUME), r8
 	and	r8, r7, r8
 	pta	work_notifysig, tr0
 	bne	r8, ZERO, tr0
diff --git a/arch/sh/kernel/entry-common.S b/arch/sh/kernel/entry-common.S
index f67601c..b96489d 100644
--- a/arch/sh/kernel/entry-common.S
+++ b/arch/sh/kernel/entry-common.S
@@ -139,7 +139,7 @@ work_pending:
 	! r8: current_thread_info
 	! t:  result of "tst	#_TIF_NEED_RESCHED, r0"
 	bf/s	work_resched
-	 tst	#_TIF_SIGPENDING, r0
+	 tst	#(_TIF_SIGPENDING | _TIF_NOTIFY_RESUME), r0
 work_notifysig:
 	bt/s	__restore_all
 	 mov	r15, r4

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Can not get output of command line on SH
  2012-08-31 13:10 ` Al Viro
@ 2012-09-03  2:56   ` Nobuhiro Iwamatsu
  2012-09-03  4:24     ` Paul Mundt
  0 siblings, 1 reply; 4+ messages in thread
From: Nobuhiro Iwamatsu @ 2012-09-03  2:56 UTC (permalink / raw)
  To: Al Viro; +Cc: Paul Mundt, Linux Kernel Mailing List

On Fri, Aug 31, 2012 at 10:10 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
> On Fri, Aug 31, 2012 at 04:32:45PM +0900, Nobuhiro Iwamatsu wrote:
>> Hi, Al.
>>
>> I can not get output of command line on SH in latest linux kernel.
>> I bisected, I confirmed that this problem occurred by  following commit.
>>
>> -----
>> commit 4a9d4b024a3102fc083c925c242d98ac27b1c5f6
>> Author: Al Viro <viro@zeniv.linux.org.uk>
>> Date:   Sun Jun 24 09:56:45 2012 +0400
>>
>>     switch fput to task_work_add
>
>> For example ,when I input 'ls', nothing is displayed.
>> However, it is outputted when 'Ctrl+C' is inputted.
>> I checked other CPUs, it is only SH that this problem occurs.
>>
>> Paul, do you think about this?
>
> Smells like broken TIF_NOTIFY_RESUME hookup on sh...  Arrrgh.  Looks like
> while it is in the relevant masks *and* checked in do_notify_resume() both
> on 32bit and 64bit variants since commit ab99c733ae73cce31f2a2434f7099564e5a73d95
> Author: Paul Mundt <lethal@linux-sh.org>
> Date:   Wed Jul 30 19:55:30 2008 +0900
>
>     sh: Make syscall tracer use tracehook notifiers, add TIF_NOTIFY_RESUME.
>
> they are actually *not* reached without simulataneous SIGPENDING, since the
> actual glue in the callers had not been updated back then and still checks
> for _TIF_SIGPENDING alone when deciding whether to hit do_notify_resume()
> or not.  Looks like the following ought to fix that:

Thanks for your reply and explanation.
I confirmed that revise this problem with your patch.

>
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>

> ---
> diff --git a/arch/sh/kernel/cpu/sh5/entry.S b/arch/sh/kernel/cpu/sh5/entry.S
> index b7cf6a5..7e605b9 100644
> --- a/arch/sh/kernel/cpu/sh5/entry.S
> +++ b/arch/sh/kernel/cpu/sh5/entry.S
> @@ -933,7 +933,7 @@ ret_with_reschedule:
>
>         pta     restore_all, tr1
>
> -       movi    _TIF_SIGPENDING, r8
> +       movi    (_TIF_SIGPENDING|_TIF_NOTIFY_RESUME), r8
>         and     r8, r7, r8
>         pta     work_notifysig, tr0
>         bne     r8, ZERO, tr0
> diff --git a/arch/sh/kernel/entry-common.S b/arch/sh/kernel/entry-common.S
> index f67601c..b96489d 100644
> --- a/arch/sh/kernel/entry-common.S
> +++ b/arch/sh/kernel/entry-common.S
> @@ -139,7 +139,7 @@ work_pending:
>         ! r8: current_thread_info
>         ! t:  result of "tst    #_TIF_NEED_RESCHED, r0"
>         bf/s    work_resched
> -        tst    #_TIF_SIGPENDING, r0
> +        tst    #(_TIF_SIGPENDING | _TIF_NOTIFY_RESUME), r0
>  work_notifysig:
>         bt/s    __restore_all
>          mov    r15, r4
> --

Best regards,
  Nobuhiro

-- 
Nobuhiro Iwamatsu

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Can not get output of command line on SH
  2012-09-03  2:56   ` Nobuhiro Iwamatsu
@ 2012-09-03  4:24     ` Paul Mundt
  0 siblings, 0 replies; 4+ messages in thread
From: Paul Mundt @ 2012-09-03  4:24 UTC (permalink / raw)
  To: Nobuhiro Iwamatsu; +Cc: Al Viro, Linux Kernel Mailing List

On Mon, Sep 03, 2012 at 11:56:59AM +0900, Nobuhiro Iwamatsu wrote:
> On Fri, Aug 31, 2012 at 10:10 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
> > Smells like broken TIF_NOTIFY_RESUME hookup on sh...  Arrrgh.  Looks like
> > while it is in the relevant masks *and* checked in do_notify_resume() both
> > on 32bit and 64bit variants since commit ab99c733ae73cce31f2a2434f7099564e5a73d95
> > Author: Paul Mundt <lethal@linux-sh.org>
> > Date:   Wed Jul 30 19:55:30 2008 +0900
> >
> >     sh: Make syscall tracer use tracehook notifiers, add TIF_NOTIFY_RESUME.
> >
> > they are actually *not* reached without simulataneous SIGPENDING, since the
> > actual glue in the callers had not been updated back then and still checks
> > for _TIF_SIGPENDING alone when deciding whether to hit do_notify_resume()
> > or not.  Looks like the following ought to fix that:
> 
> Thanks for your reply and explanation.
> I confirmed that revise this problem with your patch.
> 
> >
> > Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> Tested-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
> 
I'll queue it up, thanks!

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2012-09-03  4:24 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2012-08-31  7:32 Can not get output of command line on SH Nobuhiro Iwamatsu
2012-08-31 13:10 ` Al Viro
2012-09-03  2:56   ` Nobuhiro Iwamatsu
2012-09-03  4:24     ` Paul Mundt

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