On Thu, Jun 24, 2021 at 12:51 PM HAGIO KAZUHITO(萩尾 一仁)
<k-hagio-ab(a)nec.com> wrote:
-----Original Message-----
> > > } else {
> > > - return;
> > > + error(FATAL, "cannot determine wait queue
structure\n");
> >
> > oh, I should have checked the replacement.. this emits compilation warnings:
> >
> > $ make clean ; make warn
> > ...
> > cc -c -g -DX86_64 -DLZO -DSNAPPY -DGDB_7_6 kernel.c -Wall -O2
-Wstrict-prototypes -Wmissing-prototypes
> -fstack-protector -Wformat-security
> > kernel.c: In function 'cmd_waitq':
> > kernel.c:9380:6: warning: 'start_index' may be used uninitialized in
this function
> [-Wmaybe-uninitialized]
> > int start_index; /* where to start in wq array */
> > ^~~~~~~~~~~
> > kernel.c:9454:22: warning: 'task_offset' may be used uninitialized in
this function
> [-Wmaybe-uninitialized]
> > readmem(wq_list[i] + task_offset, KVADDR, &task,
> > ~~~~~~~~~~~^~~~~~~~~~~~~
> > kernel.c:9378:8: note: 'task_offset' was declared here
> > ulong task_offset; /* offset of task in wq element */
> > ^~~~~~~~~~~
> >
> > Hmm, in this case, I'd like to put the return back when merging.
> > Lianbo, is this ok?
> >
> > } else {
> > error(FATAL, "cannot determine wait queue
structure\n");
>
> After the log level is set to FATAL, it will exit, and the "return"
> has no chance to execute . So it could be good
> to use the log level "WARNING or INFO" for error()?
I thought this is actually a fatal level error for the waitq command,
so we should use FATAL normally, and put return with the comment to
avoid confusion. It's a little rough but lesser effort.
+ return; /* just to suppress compilation warings */
And the outputs are below respectively, I think "WARNING" in a message
implies that there is a problem but the command can continue somehow.
I don't want to use it in this case.
crash> waitq kauditd_wait
waitq: cannot determine wait queue structure // INFO
waitq: WARNING: cannot determine wait queue structure // WARNING
waitq: cannot determine wait queue structure // FATAL
So I would prefer FATAL. INFO is better?
Maybe we should keep the original changes:
- return;
+ error(FATAL, "cannot determine wait queue structure\n");
And fix the warnings directly in the kernel.c(dump_waitq()) as below:
- ulong task_offset; /* offset of task in wq element */
+ ulong task_offset = 0; /* offset of task in wq element */
int cnt; /* # elems on Queue */
- int start_index; /* where to start in wq array */
+ int start_index = -1; /* where to start in wq array */
Thanks,
Kazu