* 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 related [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
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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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