This fixes a regression in commit 4d6501dce0 where I didn't notice
that MIPS and OpenRISC were reinitialising p->{set,clear}_child_tid to
NULL after our initialisation in copy_process().
We can simply get rid of the arch-specific initialisation here since it
is now always done in copy_process() before hitting copy_thread{,_tls}().
Review notes:
- As far as I can tell, copy_process() is the only user of
copy_thread_tls(), which is the only caller of copy_thread() for
architectures that don't implement copy_thread_tls().
- After this patch, there is no arch-specific code touching
p->set_child_tid or p->clear_child_tid whatsoever.
- It may look like MIPS/OpenRISC wanted to always have these fields be
NULL, but that's not true, as copy_process() would unconditionally
set them again _after_ calling copy_thread_tls() before commit
4d6501dce0.
Fixes: 4d6501dce0 ("kthread: Fix use-after-free if kthread fork fails")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net> # MIPS only
Acked-by: Stafford Horne <shorne@gmail.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: openrisc@lists.librecores.org
Cc: Jamie Iles <jamie.iles@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
b0f5a8f32e