On Wed, 6 Jan 2010 13:13:29 -0800 (PST) Roland McGrath <roland@xxxxxxxxxx> wrote: > > However, with or without CONFIG_UTRACE, 6580807da14c423f0d0a708108e6df6ebc8bc83d > > is needed on s390 too, otherwise the child gets unnecessary traps. > > This confuses me. user_disable_single_step on non-current doesn't do > anything not already done by the memset in copy_thread. Ooh, except > perhaps it does not clear PSW_MASK_PER. Maybe that matters. That's > the only thing I can think of. Maybe Martin can make sense of it. The additional traps should not happen anymore with this patch: -- Subject: [PATCH] clear TIF_SINGLE_STEP for new process. From: Martin Schwidefsky <schwidefsky@xxxxxxxxxx> Clear the TIF_SINGLE_STEP bit in copy_thread. If the new process is not auto-attached by the tracer it is wrong to delivere SIGTRAP to the new process. Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx> --- arch/s390/kernel/process.c | 1 + 1 file changed, 1 insertion(+) diff -urpN linux-2.6/arch/s390/kernel/process.c linux-2.6-patched/arch/s390/kernel/process.c --- linux-2.6/arch/s390/kernel/process.c 2009-12-03 04:51:21.000000000 +0100 +++ linux-2.6-patched/arch/s390/kernel/process.c 2010-01-07 09:25:53.000000000 +0100 @@ -217,6 +217,7 @@ int copy_thread(unsigned long clone_flag p->thread.mm_segment = get_fs(); /* Don't copy debug registers */ memset(&p->thread.per_info, 0, sizeof(p->thread.per_info)); + clear_tsk_thread_flag(p, TIF_SINGLE_STEP); /* Initialize per thread user and system timer values */ ti = task_thread_info(p); ti->user_timer = 0; -- blue skies, Martin. "Reality continues to ruin my life." - Calvin. -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
