Hi Philippe,
The gdb test fails on xenomai 3.2 because low priority smokey process still has
chance to scheduled to
execute it's user space's task. According to my debug , it seems it is related
to handle_ptrace_resume of
dovetail/kevents.c because in failed case it would try to resume hi-thread like
stack [1] and then
hi-thread call xnthread_harden like stack [2].
But on IPIPE-xenomai image it would resume smokey thread at first and then
xnthread_harden would
be called in smokey thread in the following.
The problem is that I do know why in failed case it would xnthread_resume
hi-thread at first like log[3] but with
IPIPE-xenomai image it always xnthread_resume smokey non-rt thread like in log
[4] so that I still do not
know how to fix it. I still need more time to debug it out. Please comment.
In addition , I found that there is comments in handle_ptstep_event of
kernel/evl/thread.c. It said that
"the ptracer might have switched focus" but in gdb test case breakpoint
exactly switch to hi-thread
from smokey process . Does that means we need to do some special handle for it ?
But for me evl is quite so different from xenomai on handling
INBAND_TASK_PTSTEP in handle_inband_event.
[1]:
0xffffffff811c4020 xnthread_resume(): kernel/xenomai/thread.c, line 1039
0xffffffff811b51e0 handle_ptrace_resume(): ...ernel/xenomai/pipeline/kevents.c,
line 474
0xffffffff81078bec inband_ptstep_notify(): ./include/linux/dovetail.h, line 121
0xffffffff81078bec ptrace_resume(): kernel/ptrace.c, line 830
0xffffffff81079f32 ptrace_request(): kernel/ptrace.c, line 1194
0xffffffff8102eaab arch_ptrace(): arch/x86/kernel/ptrace.c, line 818
0xffffffff8107949b __do_sys_ptrace(): kernel/ptrace.c, line 1279
0xffffffff8107949b __se_sys_ptrace(): kernel/ptrace.c, line 1244
0xffffffff8107949b __x64_sys_ptrace(): kernel/ptrace.c, line 1244
0xffffffff81b93549 do_syscall_64(): arch/x86/entry/common.c, line 53
0xffffffff81c0007c entry_SYSCALL_64_after_hwframe(): arch/x86/entry/entry_64.S,
line 118
[2]:
0xffffffff811c6340 xnthread_harden(): kernel/xenomai/thread.c, line 1864
0xffffffff811b56fa handle_user_return(): ...ernel/xenomai/pipeline/kevents.c,
line 339
0xffffffff811b56fa handle_inband_event(): ...ernel/xenomai/pipeline/kevents.c,
line 514
0xffffffff8110791e do_retuser(): kernel/entry/common.c, line 238
0xffffffff8110791e exit_to_user_mode_prepare(): kernel/entry/common.c, line 262
0xffffffff81b97795 irqentry_exit_to_user_mode(): kernel/entry/common.c, line
356
0xffffffff81b941dc exc_int3(): arch/x86/kernel/traps.c, line 710
0xffffffff81c00aa1 asm_exc_int3(): .../arch/x86/include/asm/idtentry.h, line
592
[3]:
gdb-1153 [003] d..3 17451.761941: sched_wait_task: comm=hi-thread pid=1160
prio=97
gdb-1153 [003] d..3 17451.761944: sched_wait_task: comm=hi-thread pid=1160
prio=97
gdb-1153 [003] d..3 17451.761947: sched_wait_task: comm=hi-thread pid=1160
prio=97
gdb-1153 [003] d..3 17451.761953: sched_wait_task: comm=hi-thread pid=1160
prio=97
gdb-1153 [003] d..3 17451.761958: sched_wait_task: comm=hi-thread pid=1160
prio=97
gdb-1153 [003] d..3 17451.761973: sched_wait_task: comm=hi-thread pid=1160
prio=97
gdb-1153 [003] D..1 17451.761976: cobalt_thread_resume: name=hi-thread
pid=1160 mask=0x400000
gdb-1153 [003] D..1 17451.761977: cobalt_trace_pid: pid=1160, prio=2
gdb-1153 [003] d..3 17451.761978: sched_waking: comm=hi-thread pid=1160
prio=97 target_cpu=000
[4]
gdb-839 [000] d..1 2420.981050: signal_deliver: sig=17
errno=0 code=4 sa_handler=55bb958074d0 sa_flags=14000000
gdb-839 [000] .... 2420.981069: sched_process_wait: comm=gdb
pid=0 prio=120
gdb-839 [000] d..2 2420.981075: sched_wait_task:
comm=hi-thread pid=846 prio=97
gdb-839 [000] d..2 2420.981080: sched_wait_task:
comm=hi-thread pid=846 prio=97
gdb-839 [000] d..2 2420.981082: sched_wait_task:
comm=hi-thread pid=846 prio=97
gdb-839 [000] d..2 2420.981084: sched_wait_task:
comm=hi-thread pid=846 prio=97
gdb-839 [000] .... 2420.981087: sched_process_wait: comm=gdb
pid=0 prio=120
gdb-839 [000] d..2 2420.981147: sched_wait_task:
comm=hi-thread pid=846 prio=97
gdb-839 [000] d..2 2420.981150: sched_wait_task:
comm=hi-thread pid=846 prio=97
gdb-839 [000] d..1 2420.981303: cobalt_thread_resume:
name=smokey pid=841 mask=0x400000
gdb-839 [000] d..1 2420.981304: cobalt_thread_unblock:
pid=841 state=0x48848 info=0x0
gdb-839 [000] d..1 2420.981305: cobalt_schedule_remote:
status=0x10000000
gdb-839 [000] d..1 2420.981305: cobalt_schedule:
status=0x10000000
Regards
Hongzhan Chen
