Re: mmotm 2021-08-02-18-51 uploaded (struct user_struct when CONFIG_EPOLL is not set)

[Randy Dunlap]

On 8/2/21 10:41 PM, Randy Dunlap wrote:
> On 8/2/21 6:52 PM, akpm@xxxxxxxxxxxxxxxxxxxx wrote:
> > The mm-of-the-moment snapshot 2021-08-02-18-51 has been uploaded to
> >
> >     https://www.ozlabs.org/~akpm/mmotm/
> >
> > mmotm-readme.txt says
> >
> > README for mm-of-the-moment:
> >
> > https://www.ozlabs.org/~akpm/mmotm/
> >
> > This is a snapshot of my -mm patch queue.  Uploaded at random hopefully
> > more than once a week.
> >
> > You will need quilt to apply these patches to the latest Linus release 
> > (5.x
> > or 5.x-rcY).  The series file is in broken-out.tar.gz and is 
> > duplicated in
> > https://ozlabs.org/~akpm/mmotm/series
> >
> > The file broken-out.tar.gz contains two datestamp files: .DATE and
> > .DATE-yyyy-mm-dd-hh-mm-ss.  Both contain the string yyyy-mm-dd-hh-mm-ss,
> > followed by the base kernel version against which this patch series is to
> > be applied.
>
> I am seeing build errors on i386 or x86_64 when CONFIG_EPOLL is not set:
>
> ../kernel/user.c: In function ‘free_user’:
> ../kernel/user.c:141:30: error: ‘struct user_struct’ has no member named 
> ‘epoll_watches’; did you mean ‘nr_watches’?
>    percpu_counter_destroy(&up->epoll_watches);
>                                ^~~~~~~~~~~~~
>                                nr_watches
> In file included from ../include/linux/sched/user.h:7:0,
>                   from ../kernel/user.c:17:
> ../kernel/user.c: In function ‘alloc_uid’:
> ../kernel/user.c:189:33: error: ‘struct user_struct’ has no member named 
> ‘epoll_watches’; did you mean ‘nr_watches’?
>     if (percpu_counter_init(&new->epoll_watches, 0, GFP_KERNEL)) {
>                                   ^
> ../include/linux/percpu_counter.h:38:25: note: in definition of macro 
> ‘percpu_counter_init’
>     __percpu_counter_init(fbc, value, gfp, &__key);  \
>                           ^~~
> ../kernel/user.c:203:33: error: ‘struct user_struct’ has no member named 
> ‘epoll_watches’; did you mean ‘nr_watches’?
>      percpu_counter_destroy(&new->epoll_watches);
>                                   ^~~~~~~~~~~~~
>                                   nr_watches
> In file included from ../include/linux/sched/user.h:7:0,
>                   from ../kernel/user.c:17:
> ../kernel/user.c: In function ‘uid_cache_init’:
> ../kernel/user.c:225:37: error: ‘struct user_struct’ has no member named 
> ‘epoll_watches’; did you mean ‘nr_watches’?
>    if (percpu_counter_init(&root_user.epoll_watches, 0, GFP_KERNEL))
>                                       ^
> ../include/linux/percpu_counter.h:38:25: note: in definition of macro 
> ‘percpu_counter_init’
>     __percpu_counter_init(fbc, value, gfp, &__key);  \
>                           ^~~

Also do this change in kernel/user.c please:

        if (percpu_counter_init(&root_user.epoll_watches, 0, GFP_KERNEL))
-               panic("percpu cpunter alloc failed");
+               panic("percpu counter alloc failed");


--
~Randy
Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
https://people.kernel.org/tglx/notes-about-netiquette