On Mon, Oct 17, 2016 at 7:35 AM, Mark Rutland <mark.rutland@xxxxxxx> 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@xxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
> Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
> Cc: linux-arch@xxxxxxxxxxxxxxx
> Cc: stable@xxxxxxxxxxxxxxx # v4.2+
> Cc: uclinux-h8-devel@xxxxxxxxxxxxxxxxxxxx
> ---
> 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@xxxxxxx
>
> 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
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