On Sun, Aug 11, 2024 at 09:10:53AM -0600, Vitaliy Makkoveev wrote:
> CVSROOT: /cvs
> Module name: src
> Changes by: [email protected] 2024/08/11 09:10:53
>
> Modified files:
> sys/kern : kern_exit.c kern_fork.c kern_sysctl.c
> sys/sys : proc.h
>
> Log message:
> Make exit1() wait sysctl(2) `allprocess' loops.
>
> Regardless on wired userland memory, KERN_FILE_BYPID and KERN_FILE_BYUID
> `allprocess' loops have netlock provided sleep points, so concurrent
> process exit(1) could crash kernel.
>
> The main exit1() problem is that process teardown begins while process
> is still linked to `allprocess' list, and current code doesn't allow to
> unlink it first. Wait for concurrent sysctl(2) `allprocess' loops
> between PS_EXITING bit setting and list unlinking. Both KERN_FILE_BYPID
> and KERN_FILE_BYUID loops do PS_EXITING check and won't deal with dying
> process. Concurrent exit1() thread will wait loops keeping process
> linked to `allprocess' list.
>
> Tested with i386 dpb(1) run.
> Stress tests and ok bluhm.
>
libkvm fails to build with this diff because userland doesn't know about
struct refcount:
cc -O2 -pipe -g -D_LIBKVM -MD -MP -c /usr/src/lib/libkvm/kvm_proc.c -o
kvm_proc.o
In file included from /usr/src/lib/libkvm/kvm_proc.c:76:
/usr/include/sys/proc.h:145:16: error: field has incomplete type 'struct refcnt'
struct refcnt ps_refcnt;
^
