On Thu, Jun 24, 2021 at 12:51 PM HAGIO KAZUHITO(萩尾 一仁)
<k-hagio-ab@xxxxxxx> 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
>
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