Re: [Crash-utility] [RFC/PATCH] s390x: Add live dump detection

Hello Dave, On Mon, 23 Apr 2012 08:50:02 -0400 (EDT) Dave Anderson <anderson(a)redhat.com&gt; wrote: [snip] > > > Question: how does that code path ever get run? Interesting... I only tested the patch on a live dump and not on the live system with /dev/mem. Therefore I did not see that. On a live system, as you described it, the s390x.c code is not used. > > If you try a "bt" on an active task on a live system, it would > print the "(active)" here in back_trace(), prior to calling into > the machine-specific backtrace function: > > if (ACTIVE() && !(bt->flags & BT_EFRAME_SEARCH) && > ((bt->task == tt->this_task) || is_task_active(bt->task))) { > > if (BT_REFERENCE_CHECK(bt) || > bt->flags & (BT_TEXT_SYMBOLS_PRINT|BT_TEXT_SYMBOLS_NOPRINT)) > return; > > if (!(bt->flags & > (BT_KSTACKP|BT_TEXT_SYMBOLS|BT_TEXT_SYMBOLS_ALL))) > fprintf(fp, "(active)\n"); > > if (!(bt->flags & (BT_TEXT_SYMBOLS|BT_TEXT_SYMBOLS_ALL))) > return; > } > > Note the "bt -[tT]" options should be allowed even if the task is active. So the check should be done in kernel.c and not in s390x.c. Would the following patch be better?

--- kernel.c | 2 +- s390x.c | 4 ---- 2 files changed, 1 insertion(+), 5 deletions(-) --- a/kernel.c +++ b/kernel.c @@ -2245,7 +2245,7 @@ back_trace(struct bt_info *bt) return; } - if (ACTIVE() && !(bt->flags & BT_EFRAME_SEARCH) && + if (LIVE() && !(bt->flags & BT_EFRAME_SEARCH) && ((bt->task == tt->this_task) || is_task_active(bt->task))) { if (BT_REFERENCE_CHECK(bt) || --- a/s390x.c +++ b/s390x.c @@ -1092,10 +1092,6 @@ static void s390x_back_trace_cmd(struct * Print lowcore and print interrupt stacks when task has cpu */ if (s390x_has_cpu(bt)) { - if (ACTIVE()) { - fprintf(fp,"(active)\n"); - return; - } s390x_get_lowcore(bt, lowcore); psw_flags = ULONG(lowcore + OFFSET(s390_lowcore_psw_save_area));