* 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
end of thread, other threads:[~2012-09-03 4:24 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 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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