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* [PATCH RESEND] h8300: fix syscall restarting
@ 2016-10-17 14:35 Mark Rutland
  2016-10-17 17:04 ` Andy Lutomirski
  0 siblings, 1 reply; 3+ messages in thread
From: Mark Rutland @ 2016-10-17 14:35 UTC (permalink / raw)
  To: ysato
  Cc: Mark Rutland, Andrew Morton, Andy Lutomirski, linux-arch,
	uclinux-h8-devel

Back in commit f56141e3e2d9aabf ("all arches, signal: move restart_block
to struct task_struct"), all architectures and core code were changed to
use task_struct::restart_block. However, when h8300 support was
subsequently restored in v4.2, it was not updated to account for this,
and maintains thread_info::restart_block, which is not kept in sync.

This patch drops the redundant restart_block from thread_info, and moves
h8300 to the common one in task_struct, ensuring that syscall restarting
always works as expected.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: linux-arch@vger.kernel.org
Cc: stable@vger.kernel.org # v4.2+
Cc: uclinux-h8-devel@lists.sourceforge.jp
---
 arch/h8300/include/asm/thread_info.h | 4 ----
 arch/h8300/kernel/signal.c           | 2 +-
 2 files changed, 1 insertion(+), 5 deletions(-)

This was previously sent as a reply to another patch [1], and then subsequently
on its own [2], but I haven't heard anything for about three weeks since the
last posting.

This happens to get in the way of moving thread_info into task_struct on some
architectures as it implicitly relies on include ordering in a core header. I
have a workaround for that, but this does seem like a major bug regardless...

Mark.

[1] http://lkml.kernel.org/r/20160919104254.GA12473@leverpostej
[2] http://lkml.kernel.org/r/1474918434-3870-1-git-send-email-mark.rutland@arm.com

diff --git a/arch/h8300/include/asm/thread_info.h b/arch/h8300/include/asm/thread_info.h
index b408fe6..3cef068 100644
--- a/arch/h8300/include/asm/thread_info.h
+++ b/arch/h8300/include/asm/thread_info.h
@@ -31,7 +31,6 @@ struct thread_info {
 	int		   cpu;			/* cpu we're on */
 	int		   preempt_count;	/* 0 => preemptable, <0 => BUG */
 	mm_segment_t		addr_limit;
-	struct restart_block restart_block;
 };
 
 /*
@@ -44,9 +43,6 @@ struct thread_info {
 	.cpu =		0,			\
 	.preempt_count = INIT_PREEMPT_COUNT,	\
 	.addr_limit	= KERNEL_DS,		\
-	.restart_block	= {			\
-		.fn = do_no_restart_syscall,	\
-	},					\
 }
 
 #define init_thread_info	(init_thread_union.thread_info)
diff --git a/arch/h8300/kernel/signal.c b/arch/h8300/kernel/signal.c
index ad1f81f..7138303 100644
--- a/arch/h8300/kernel/signal.c
+++ b/arch/h8300/kernel/signal.c
@@ -79,7 +79,7 @@ struct rt_sigframe {
 	unsigned int er0;
 
 	/* Always make any pending restarted system calls return -EINTR */
-	current_thread_info()->restart_block.fn = do_no_restart_syscall;
+	current->restart_block.fn = do_no_restart_syscall;
 
 	/* restore passed registers */
 #define COPY(r)  do { err |= get_user(regs->r, &usc->sc_##r); } while (0)
-- 
1.9.1

^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH RESEND] h8300: fix syscall restarting
  2016-10-17 14:35 [PATCH RESEND] h8300: fix syscall restarting Mark Rutland
@ 2016-10-17 17:04 ` Andy Lutomirski
  2016-10-17 17:09   ` Mark Rutland
  0 siblings, 1 reply; 3+ messages in thread
From: Andy Lutomirski @ 2016-10-17 17:04 UTC (permalink / raw)
  To: Mark Rutland; +Cc: Yoshinori Sato, Andrew Morton, linux-arch, uclinux-h8-devel

On Mon, Oct 17, 2016 at 7:35 AM, Mark Rutland <mark.rutland@arm.com> wrote:
> Back in commit f56141e3e2d9aabf ("all arches, signal: move restart_block
> to struct task_struct"), all architectures and core code were changed to
> use task_struct::restart_block. However, when h8300 support was
> subsequently restored in v4.2, it was not updated to account for this,
> and maintains thread_info::restart_block, which is not kept in sync.
>
> This patch drops the redundant restart_block from thread_info, and moves
> h8300 to the common one in task_struct, ensuring that syscall restarting
> always works as expected.

This is Obviously Correct (tm).  Should it have a cc: stable?

--Andy

>
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Andy Lutomirski <luto@amacapital.net>
> Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
> Cc: linux-arch@vger.kernel.org
> Cc: stable@vger.kernel.org # v4.2+
> Cc: uclinux-h8-devel@lists.sourceforge.jp
> ---
>  arch/h8300/include/asm/thread_info.h | 4 ----
>  arch/h8300/kernel/signal.c           | 2 +-
>  2 files changed, 1 insertion(+), 5 deletions(-)
>
> This was previously sent as a reply to another patch [1], and then subsequently
> on its own [2], but I haven't heard anything for about three weeks since the
> last posting.
>
> This happens to get in the way of moving thread_info into task_struct on some
> architectures as it implicitly relies on include ordering in a core header. I
> have a workaround for that, but this does seem like a major bug regardless...
>
> Mark.
>
> [1] http://lkml.kernel.org/r/20160919104254.GA12473@leverpostej
> [2] http://lkml.kernel.org/r/1474918434-3870-1-git-send-email-mark.rutland@arm.com
>
> diff --git a/arch/h8300/include/asm/thread_info.h b/arch/h8300/include/asm/thread_info.h
> index b408fe6..3cef068 100644
> --- a/arch/h8300/include/asm/thread_info.h
> +++ b/arch/h8300/include/asm/thread_info.h
> @@ -31,7 +31,6 @@ struct thread_info {
>         int                cpu;                 /* cpu we're on */
>         int                preempt_count;       /* 0 => preemptable, <0 => BUG */
>         mm_segment_t            addr_limit;
> -       struct restart_block restart_block;
>  };
>
>  /*
> @@ -44,9 +43,6 @@ struct thread_info {
>         .cpu =          0,                      \
>         .preempt_count = INIT_PREEMPT_COUNT,    \
>         .addr_limit     = KERNEL_DS,            \
> -       .restart_block  = {                     \
> -               .fn = do_no_restart_syscall,    \
> -       },                                      \
>  }
>
>  #define init_thread_info       (init_thread_union.thread_info)
> diff --git a/arch/h8300/kernel/signal.c b/arch/h8300/kernel/signal.c
> index ad1f81f..7138303 100644
> --- a/arch/h8300/kernel/signal.c
> +++ b/arch/h8300/kernel/signal.c
> @@ -79,7 +79,7 @@ struct rt_sigframe {
>         unsigned int er0;
>
>         /* Always make any pending restarted system calls return -EINTR */
> -       current_thread_info()->restart_block.fn = do_no_restart_syscall;
> +       current->restart_block.fn = do_no_restart_syscall;
>
>         /* restore passed registers */
>  #define COPY(r)  do { err |= get_user(regs->r, &usc->sc_##r); } while (0)
> --
> 1.9.1
>



-- 
Andy Lutomirski
AMA Capital Management, LLC

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH RESEND] h8300: fix syscall restarting
  2016-10-17 17:04 ` Andy Lutomirski
@ 2016-10-17 17:09   ` Mark Rutland
  0 siblings, 0 replies; 3+ messages in thread
From: Mark Rutland @ 2016-10-17 17:09 UTC (permalink / raw)
  To: Andy Lutomirski
  Cc: Yoshinori Sato, Andrew Morton, linux-arch, uclinux-h8-devel

On Mon, Oct 17, 2016 at 10:04:32AM -0700, Andy Lutomirski wrote:
> On Mon, Oct 17, 2016 at 7:35 AM, Mark Rutland <mark.rutland@arm.com> wrote:
> > Back in commit f56141e3e2d9aabf ("all arches, signal: move restart_block
> > to struct task_struct"), all architectures and core code were changed to
> > use task_struct::restart_block. However, when h8300 support was
> > subsequently restored in v4.2, it was not updated to account for this,
> > and maintains thread_info::restart_block, which is not kept in sync.
> >
> > This patch drops the redundant restart_block from thread_info, and moves
> > h8300 to the common one in task_struct, ensuring that syscall restarting
> > always works as expected.
> 
> This is Obviously Correct (tm). Should it have a cc: stable?

> > Cc: stable@vger.kernel.org # v4.2+

Yes. ;)

I must've messed up with git-send-email for the "real" Cc list.

Thanks,
Mark.

> > Cc: uclinux-h8-devel@lists.sourceforge.jp
> > ---
> >  arch/h8300/include/asm/thread_info.h | 4 ----
> >  arch/h8300/kernel/signal.c           | 2 +-
> >  2 files changed, 1 insertion(+), 5 deletions(-)
> >
> > This was previously sent as a reply to another patch [1], and then subsequently
> > on its own [2], but I haven't heard anything for about three weeks since the
> > last posting.
> >
> > This happens to get in the way of moving thread_info into task_struct on some
> > architectures as it implicitly relies on include ordering in a core header. I
> > have a workaround for that, but this does seem like a major bug regardless...
> >
> > Mark.
> >
> > [1] http://lkml.kernel.org/r/20160919104254.GA12473@leverpostej
> > [2] http://lkml.kernel.org/r/1474918434-3870-1-git-send-email-mark.rutland@arm.com
> >
> > diff --git a/arch/h8300/include/asm/thread_info.h b/arch/h8300/include/asm/thread_info.h
> > index b408fe6..3cef068 100644
> > --- a/arch/h8300/include/asm/thread_info.h
> > +++ b/arch/h8300/include/asm/thread_info.h
> > @@ -31,7 +31,6 @@ struct thread_info {
> >         int                cpu;                 /* cpu we're on */
> >         int                preempt_count;       /* 0 => preemptable, <0 => BUG */
> >         mm_segment_t            addr_limit;
> > -       struct restart_block restart_block;
> >  };
> >
> >  /*
> > @@ -44,9 +43,6 @@ struct thread_info {
> >         .cpu =          0,                      \
> >         .preempt_count = INIT_PREEMPT_COUNT,    \
> >         .addr_limit     = KERNEL_DS,            \
> > -       .restart_block  = {                     \
> > -               .fn = do_no_restart_syscall,    \
> > -       },                                      \
> >  }
> >
> >  #define init_thread_info       (init_thread_union.thread_info)
> > diff --git a/arch/h8300/kernel/signal.c b/arch/h8300/kernel/signal.c
> > index ad1f81f..7138303 100644
> > --- a/arch/h8300/kernel/signal.c
> > +++ b/arch/h8300/kernel/signal.c
> > @@ -79,7 +79,7 @@ struct rt_sigframe {
> >         unsigned int er0;
> >
> >         /* Always make any pending restarted system calls return -EINTR */
> > -       current_thread_info()->restart_block.fn = do_no_restart_syscall;
> > +       current->restart_block.fn = do_no_restart_syscall;
> >
> >         /* restore passed registers */
> >  #define COPY(r)  do { err |= get_user(regs->r, &usc->sc_##r); } while (0)
> > --
> > 1.9.1
> >
> 
> -- 
> Andy Lutomirski
> AMA Capital Management, LLC
> 

^ permalink raw reply	[flat|nested] 3+ messages in thread

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2016-10-17 14:35 [PATCH RESEND] h8300: fix syscall restarting Mark Rutland
2016-10-17 17:04 ` Andy Lutomirski
2016-10-17 17:09   ` Mark Rutland

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