Re: s390 user_enable_single_step() (Was: odd utrace testing results on s390x)

2010-01-06 Thread Heiko Carstens
On Tue, Jan 05, 2010 at 08:58:18PM +0100, Oleg Nesterov wrote: I decided to re-test this all with vanilla 2.6.33-rc2. It is really amazing how long it takes to recompile/install the kernel! Then either you have a lot of steal time or an old machine (pre z10)? You could also try to define more

Re: s390 user_enable_single_step() (Was: odd utrace testing results on s390x)

2010-01-06 Thread caiqian
Cai, any chance you can help? Using /usr/bin/console I can't choose anotherkernel at the 00: Please choose (default will boot in 15 seconds): stage, how can I do this??? As Heiko mentioned, I did manage to enter, #cp vi vmsg 2 during the prompt to get to the second kernel to boot...

Re: s390 user_enable_single_step() (Was: odd utrace testing results on s390x)

2010-01-06 Thread Oleg Nesterov
On 01/06, caiq...@redhat.com wrote: Cai, any chance you can help? Using /usr/bin/console I can't choose anotherkernel at the 00: Please choose (default will boot in 15 seconds): stage, how can I do this??? As Heiko mentioned, I did manage to enter, #cp vi vmsg 2 if only I new about

Re: s390 user_enable_single_step() (Was: odd utrace testing results on s390x)

2010-01-06 Thread Oleg Nesterov
On 01/05, Oleg Nesterov wrote: On 01/05, Oleg Nesterov wrote: On 01/05, Oleg Nesterov wrote: I'll add clear_bit(TIF_SINGLE_STEP) into do_fork() path and re-test. Hmm. This patch --- kernel/fork.c~ 2009-12-22 10:41:53.188084961 -0500 +++ kernel/fork.c

Re: s390 user_enable_single_step() (Was: odd utrace testing results on s390x)

2010-01-06 Thread Oleg Nesterov
On 01/05, Martin Schwidefsky wrote: On Mon, 4 Jan 2010 13:11:47 -0800 (PST) Roland McGrath rol...@redhat.com wrote: This probably means that copy_process()-user_disable_single_step() is not enough to clear the this task wants single-stepping copied from parent. I would suspect

Re: s390 user_enable_single_step() (Was: odd utrace testing results on s390x)

2010-01-06 Thread Roland McGrath
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