Messages in this thread | | | Date | Thu, 4 Nov 2010 11:43:49 +0800 | From | Wu Fengguang <> | Subject | Re: [2.6.37-rc1] /proc/vmstat failure. |
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On Thu, Nov 04, 2010 at 11:31:48AM +0800, Américo Wang wrote: > On Thu, Nov 04, 2010 at 10:53:41AM +0800, Wu Fengguang wrote: > >On Thu, Nov 04, 2010 at 10:52:51AM +0800, Américo Wang wrote: > >> On Thu, Nov 04, 2010 at 10:20:52AM +0800, Wu Fengguang wrote: > >> >On Thu, Nov 04, 2010 at 05:54:48AM +0800, Tetsuo Handa wrote: > >> >> Wu Fengguang wrote: > >> >> > On Wed, Nov 03, 2010 at 07:11:11PM +0800, Tetsuo Handa wrote: > >> >> > > Hello. > >> >> > > > >> >> > > "cat /proc/vmstat" triggered below failure. > >> >> > > > >> >> > > BUG: unable to handle kernel paging request at 07c06d16 > >> >> > > IP: [<c050c336>] strnlen+0x6/0x20 > >> >> > > >> >> > It seems that m->private is of type (void *) while the original v is > >> >> > (unsigned long *). Can be fixed by the following patch. > >> >> > >> >> Fixed by this patch. Thank you. > >> > > >> >Great, thanks! > >> > > >> >> By the way, GCC treats "(void *) + offset" as "(char *) + offset" > >> >> but it is GCC specific extention. Maybe we should avoid such usage > >> >> in order to avoid build failure for other compilers. > >> > > >> >"(void *) + offset" seems to be used quite often. > >> > > >> >I tried enable this gcc option, only to see huge amount of warnings. > >> > > >> > -Wpointer-arith > >> > Warn about anything that depends on the "size of" a > >> > function type or of "void". GNU C assigns these types a > >> > size of 1, for convenience in calculations with "void *" > >> > pointers and pointers to functions. > >> > > >> > >> Yup! I think it is good to have this. > >> > >> >/cc/linux-next/scripts/mod/file2alias.c:88: warning: pointer of type ‘void *’ used in arithmetic > >> ... > >> >/cc/linux-next/scripts/mod/modpost.c:1565: warning: pointer of type ‘void *’ used in arithmetic > >> > > >> > >> No problem, this is from kbuild and most of them that I checked are actually fine, > >> we can send patches to remove these warnings. > > > >Confirmed. Now my full kernel build is complete and the above are the > >only warnings I see. So it should be easy to add the -Wpointer-arith > >check. > > > > Well, after I tried to compile with it, I got lots of warnings. > Most of them that I checked is something like: > > (void *) CONST_PTR + OFFSET > > in macros. In order to fix this, we need to: > > (void *) ((char *) CONST_PTR + OFFSET) > > So, we have to make some efforts to kill all the warnings. :-/
Sorry I didn't run allyesconfig/allmodconfig as suggested by Tetsuo. So expect more warnings..
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