[Crash-utility] [PATCH] Fix 'waitq' command for 4.13 and later kernels

[HAGIO KAZUHITO(萩尾 一仁)]

Hi Greg,

I'm resending with cc, my email client dropped it automatically..

(We would recommend subscribing to the mailing list so that you can receive
replies certainly.)

Thanks,
Kazu

-----Original Message-----
> Hi Greg,
> 
> -----Original Message-----
> > The wait queue structs and members were renamed in 4.13.  Add support to
> > the 'waitq' command for these more recent kernels.
> 
> Thanks for the patch, good catch.
> 
> (Ah, my test has missed the command..)
> 
> It would be helpful if you add the kernel commits to the commit log,
> I think they are ac6424b981bce1c4bc55675c6ce11bfe1bbfa64f and
> 9d9d676f595b5081326be7a17dc681fcb38fb3b2.
> 
> >
> > Signed-off-by: Greg Edwards <gedwards at ddn.com>
> > ---
> >  defs.h    |  4 ++++
> >  kernel.c  | 23 +++++++++++++++++++++--
> >  symbols.c |  8 +++++++-
> >  3 files changed, 32 insertions(+), 3 deletions(-)
> >
> > diff --git a/defs.h b/defs.h
> > index 42c8074e6ac6..170e9cba724f 100644
> > --- a/defs.h
> > +++ b/defs.h
> > @@ -1589,6 +1589,9 @@ struct offset_table {                    /* stash of commonly-used offsets */
> >   	long __wait_queue_task;
> >  	long __wait_queue_head_task_list;
> >   	long __wait_queue_task_list;
> > +	long wait_queue_entry_private;
> > +	long wait_queue_head_head;
> > +	long wait_queue_entry_entry;
> >  	long pglist_data_node_zones;
> >  	long pglist_data_node_mem_map;
> >  	long pglist_data_node_start_paddr;
> > @@ -2188,6 +2191,7 @@ struct size_table {         /* stash of commonly-used sizes */
> >  	long tvec_t_base_s;
> >  	long wait_queue;
> >  	long __wait_queue;
> > +	long wait_queue_entry;
> 
> Would you move these offsets and size to the end of its table?
> to avoid breaking previously compiled extension modules.
> 
> (ref. crash's contribution guidelines: https://github.com/crash-utility/crash/wiki)
> 
> 
> >  	long device;
> >  	long net_device;
> >  	long sock;
> > diff --git a/kernel.c b/kernel.c
> > index 528f6ee524f6..1d50a7200e42 100644
> > --- a/kernel.c
> > +++ b/kernel.c
> > @@ -614,8 +614,16 @@ kernel_init()
> >  	} else if (symbol_exists("tvec_bases"))
> >  		kt->flags |= TVEC_BASES_V1;
> >
> > -        STRUCT_SIZE_INIT(__wait_queue, "__wait_queue");
> > -        if (VALID_STRUCT(__wait_queue)) {
> > +	STRUCT_SIZE_INIT(wait_queue_entry, "wait_queue_entry");
> > +	if (VALID_STRUCT(wait_queue_entry)) {
> > +		MEMBER_OFFSET_INIT(wait_queue_entry_private,
> > +			"wait_queue_entry", "private");
> > +		MEMBER_OFFSET_INIT(wait_queue_head_head,
> > +			"wait_queue_head", "head");
> > +		MEMBER_OFFSET_INIT(wait_queue_entry_entry,
> > +			"wait_queue_entry", "entry");
> > +	} else if (VALID_STRUCT(__wait_queue)) {
> > +		STRUCT_SIZE_INIT(__wait_queue, "__wait_queue");
> 
> The VALID_STRUCT(__wait_queue) macro can be used after calling
> STRUCT_SIZE_INIT(__wait_queue, "__wait_queue"), so please move this
> prior to the if block.
> 
> >  		if (MEMBER_EXISTS("__wait_queue", "task"))
> >  			MEMBER_OFFSET_INIT(__wait_queue_task,
> >  				"__wait_queue", "task");
> > @@ -9397,6 +9405,17 @@ dump_waitq(ulong wq, char *wq_name)
> >                  ld->list_head_offset = OFFSET(__wait_queue_task_list);
> >                  ld->member_offset = next_offset;
> >
> > +		start_index = 1;
> > +	} else if (VALID_STRUCT(wait_queue_entry)) {
> > +		ulong task_list_offset;
> > +
> > +                next_offset = OFFSET(list_head_next);
> > +                task_offset = OFFSET(wait_queue_entry_private);
> > +                task_list_offset = OFFSET(wait_queue_head_head);
> > +                ld->end = ld->start = wq + task_list_offset + next_offset;
> > +                ld->list_head_offset = OFFSET(wait_queue_entry_entry);
> > +                ld->member_offset = next_offset;
> > +
> >  		start_index = 1;
> >  	} else {
> >  		return;
> 
> Personally I would like to add a message to inform the structure change
> so that my test can detect it.  So could you replace the return with this?
> 
>   error(FATAL, "cannot determine wait queue structure\n");
> 
> 
> > diff --git a/symbols.c b/symbols.c
> > index 370d4c3e8ac0..72eea43871bb 100644
> > --- a/symbols.c
> > +++ b/symbols.c
> > @@ -9817,7 +9817,13 @@ dump_offset_table(char *spec, ulong makestruct)
> >          	OFFSET(__wait_queue_head_task_list));
> >          fprintf(fp, "        __wait_queue_task_list: %ld\n",
> >          	OFFSET(__wait_queue_task_list));
> > -
> > +	fprintf(fp, "        wait_queue_entry_private: %ld\n",
> > +		OFFSET(wait_queue_entry_private));
> > +	fprintf(fp, "        wait_queue_head_head: %ld\n",
> > +		OFFSET(wait_queue_head_head));
> > +	fprintf(fp, "        wait_queue_entry_entry: %ld\n",
> > +		OFFSET(wait_queue_entry_entry));
> > +
> 
> Please print also SIZE(wait_queue_entry).
> 
> Thanks,
> Kazu
> 
> >  	fprintf(fp, "        pglist_data_node_zones: %ld\n",
> >  		OFFSET(pglist_data_node_zones));
> >  	fprintf(fp, "      pglist_data_node_mem_map: %ld\n",
> > --
> > 2.32.0
> >
> >
> > --
> > Crash-utility mailing list
> > Crash-utility at redhat.com
> > https://listman.redhat.com/mailman/listinfo/crash-utility
> 
> 
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