<div dir="ltr"><div dir="ltr">On Mon, Jun 12, 2023 at 7:24 PM Daisuke Hatayama (Fujitsu) <<a href="mailto:d.hatayama@fujitsu.com">d.hatayama@fujitsu.com</a>> wrote:<br></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">> Thank you for pointing out this issue, HATAYAMA.<br>
><br>
> Anyway, I did not reproduce the above issue. Seems it can not always be reproduced.<br>
><br>
> # ./crash /home/vmlinux /var/crash/127.0.0.1-2023-06-09-05\:20\:38/vmcore -s<br>
> WARNING: cpu 2: invalid NT_PRSTATUS note (n_type != NT_PRSTATUS)<br>
> WARNING: cpu 1: cannot find NT_PRSTATUS note<br>
> WARNING: cpu 2: cannot find NT_PRSTATUS note<br>
> crash> ps insmod<br>
> PID PPID CPU TASK ST %MEM VSZ RSS COMM<br>
> 1684 1683 0 ffff06738f1cdd00 ZO 0.0 0 0 insmod<br>
> crash> bt 1684<br>
> PID: 1684 TASK: ffff06738f1cdd00 CPU: 0 COMMAND: "insmod"<br>
> (no stack)<br>
> crash><br>
<br>
The problematic case is the active tasks running in user mode at the<br>
moment of kernel panic. In most cases, it's enough to prepare some<br>
programs that running in infinite loop just like:<br>
<br>
# while : ; do continue ; done &<br>
[3] 3295<br>
<br>
Just in case, note that this issue is different from the one of<br>
corrupt mapping of NT_PRSTATUS notes. You don't need to use the<br></blockquote><div><br></div><div>Thank you for the explanation, HATAYAMA. It's true, they are different issues, that is why it can not always be reproduced.</div><div>crash> ps insmod<br> PID PPID CPU TASK ST %MEM VSZ RSS COMM<br> 1696 1695 2 ffff2e420cf5a900 RU 0.0 7168 3840 insmod<br>crash> bt 1696<br>PID: 1696 TASK: ffff2e420cf5a900 CPU: 2 COMMAND: "insmod"<br> #0 [ffff800013eefae0] __switch_to at ffffc029d3cc9d24<br> #1 [ffff800013eefb10] __schedule at ffffc029d475c1fc<br> #2 [ffff800013eefba0] preempt_schedule_common at ffffc029d475cd7c<br> #3 [ffff800013eefbb0] _cond_resched at ffffc029d475cdc8<br> #4 [ffff800013eefbc0] down_read at ffffc029d475fdbc<br> #5 [ffff800013eefbe0] blocking_notifier_call_chain at ffffc029d3d66024<br> #6 [ffff800013eefc10] do_init_module at ffffc029d3e1040c<br> #7 [ffff800013eefc40] load_module at ffffc029d3e12948<br> #8 [ffff800013eefda0] __se_sys_finit_module at ffffc029d3e12ebc<br> #9 [ffff800013eefe60] __arm64_sys_finit_module at ffffc029d3e12f7c<br>#10 [ffff800013eefe80] do_el0_svc at ffffc029d3cd9300<br>#11 [ffff800013eefeb0] el0_sync_handler at ffffc029d3cc9374<br>#12 [ffff800013eefff0] el0_sync at ffffc029d3cc2b7c<br> PC: 0000ffff9b7637e4 LR: 0000aaaabe6b3e48 SP: 0000ffffc6f33810<br> X29: 0000ffffc6f33810 X28: 0000000000000000 X27: 0000000000000000<br> X26: 0000000000000002 X25: 0000000000000000 X24: 0000ffffc6f338e8<br> X23: 0000aaaad7da1840 X22: 0000000000000000 X21: 0000000000000000<br> X20: 0000aaaabe6bd520 X19: 0000aaaad7da1860 X18: 0000000000000000<br> X17: 0000ffff9b7637c0 X16: 0000aaaabe6dfd98 X15: 0000000000000070<br> X14: 0000000000000002 X13: 000000000000270f X12: 0000000000000000<br> X11: 0000000000000000 X10: 0000000000000000 X9: 0000aaaad7da1960<br> X8: 0000000000000111 X7: 0000000000000001 X6: 0000000000000001<br> X5: 0000000000000db1 X4: 0000000000000000 X3: 0000000000000003<br> X2: 0000000000000000 X1: 0000aaaabe6bd520 X0: 0000000000000003<br> ORIG_X0: 0000000000000003 SYSCALLNO: 111 PSTATE: 40001000<br></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
reproduction steps I shared. It's enough to prepare the above busy<br>
loop process in advance, make the kernel panic and then use bt command<br>
for the busy loop process.<br></blockquote><div><br></div><div>You are right. I have reproduced the current problem with an infinite loop process.</div><div><br></div><div> crash> ps t</div> PID PPID CPU TASK ST %MEM VSZ RSS COMM<br>> 8419 1896 2 ffff08aa9360ff00 RU 0.0 2432 1216 t<br>crash> bt 8419<br>PID: 8419 TASK: ffff08aa9360ff00 CPU: 2 COMMAND: "t"<br>bt: invalid stack pointer is given</div><div class="gmail_quote"><br></div><div class="gmail_quote">I have no other issues about it.</div><div class="gmail_quote"><br></div><div class="gmail_quote">Thanks.</div><div class="gmail_quote">Lianbo</div><div class="gmail_quote"><br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<br>
Thanks.<br>
HATAYAMA, Daisuke<br>
<br>
<br>
</blockquote></div></div>