Re: [tip:WIP.sched/core 19/22] kernel/sched/core.c:2836:18: error: passing argument 1 of 'mips_install_watch_registers' from incompatible pointer type
From: Randy Dunlap
Date: Sun Mar 04 2018 - 13:12:57 EST
On 03/04/2018 02:52 AM, kbuild test robot wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git WIP.sched/core
> head: ffce6fffa0033fa54d1bac1c7494862b71316978
> commit: ecaf52c9ec5ad31395e5c06c01e293ebcf0e4350 [19/22] sched/headers: Simplify and clean up header usage in the scheduler
> config: mips-jz4740 (attached as .config)
> compiler: mipsel-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
> reproduce:
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> git checkout ecaf52c9ec5ad31395e5c06c01e293ebcf0e4350
> # save the attached .config to linux build tree
> make.cross ARCH=mips
>
> All error/warnings (new ones prefixed by >>):
>
> In file included from arch/mips/include/asm/switch_to.h:16:0,
> from kernel/sched/core.c:8:
>>> arch/mips/include/asm/watch.h:15:42: warning: 'struct task_struct' declared inside parameter list will not be visible outside of this definition or declaration
> void mips_install_watch_registers(struct task_struct *t);
> ^~~~~~~~~~~
> In file included from arch/mips/include/asm/switch_to.h:16:0,
> from kernel/sched/core.c:8:
> kernel/sched/core.c: In function 'context_switch':
>>> kernel/sched/core.c:2836:18: error: passing argument 1 of 'mips_install_watch_registers' from incompatible pointer type [-Werror=incompatible-pointer-types]
> switch_to(prev, next, prev);
> ^
> arch/mips/include/asm/watch.h:24:32: note: in definition of macro '__restore_watch'
> mips_install_watch_registers(task); \
> ^~~~
> kernel/sched/core.c:2836:2: note: in expansion of macro 'switch_to'
> switch_to(prev, next, prev);
> ^~~~~~~~~
> arch/mips/include/asm/watch.h:15:6: note: expected 'struct task_struct *' but argument is of type 'struct task_struct *'
> void mips_install_watch_registers(struct task_struct *t);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
> cc1: some warnings being treated as errors
> --
> In file included from arch/mips/include/asm/switch_to.h:16:0,
> from kernel//sched/core.c:8:
>>> arch/mips/include/asm/watch.h:15:42: warning: 'struct task_struct' declared inside parameter list will not be visible outside of this definition or declaration
> void mips_install_watch_registers(struct task_struct *t);
> ^~~~~~~~~~~
> In file included from arch/mips/include/asm/switch_to.h:16:0,
> from kernel//sched/core.c:8:
> kernel//sched/core.c: In function 'context_switch':
> kernel//sched/core.c:2836:18: error: passing argument 1 of 'mips_install_watch_registers' from incompatible pointer type [-Werror=incompatible-pointer-types]
> switch_to(prev, next, prev);
> ^
> arch/mips/include/asm/watch.h:24:32: note: in definition of macro '__restore_watch'
> mips_install_watch_registers(task); \
> ^~~~
> kernel//sched/core.c:2836:2: note: in expansion of macro 'switch_to'
> switch_to(prev, next, prev);
> ^~~~~~~~~
> arch/mips/include/asm/watch.h:15:6: note: expected 'struct task_struct *' but argument is of type 'struct task_struct *'
> void mips_install_watch_registers(struct task_struct *t);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
> cc1: some warnings being treated as errors
I don't have a tip git repo, but it looks like this would fix it (based on most
recent -next):
--- linux-next-20180302.orig/arch/mips/include/asm/watch.h
+++ linux-next-20180302/arch/mips/include/asm/watch.h
@@ -12,6 +12,8 @@
#include <asm/mipsregs.h>
+struct task_struct;
+
void mips_install_watch_registers(struct task_struct *t);
void mips_read_watch_registers(void);
void mips_clear_watch_registers(void);
> vim +/mips_install_watch_registers +2836 kernel/sched/core.c
>
> ^1da177e kernel/sched.c Linus Torvalds 2005-04-16 2791
> ^1da177e kernel/sched.c Linus Torvalds 2005-04-16 2792 /*
> dfa50b60 kernel/sched/core.c Oleg Nesterov 2014-10-09 2793 * context_switch - switch to the new MM and the new thread's register state.
> ^1da177e kernel/sched.c Linus Torvalds 2005-04-16 2794 */
> 04936948 kernel/sched/core.c Josh Poimboeuf 2016-02-28 2795 static __always_inline struct rq *
> 70b97a7f kernel/sched.c Ingo Molnar 2006-07-03 2796 context_switch(struct rq *rq, struct task_struct *prev,
> d8ac8971 kernel/sched/core.c Matt Fleming 2016-09-21 2797 struct task_struct *next, struct rq_flags *rf)
> ^1da177e kernel/sched.c Linus Torvalds 2005-04-16 2798 {
> dd41f596 kernel/sched.c Ingo Molnar 2007-07-09 2799 struct mm_struct *mm, *oldmm;
> ^1da177e kernel/sched.c Linus Torvalds 2005-04-16 2800
> e107be36 kernel/sched.c Avi Kivity 2007-07-26 2801 prepare_task_switch(rq, prev, next);
> fe4b04fa kernel/sched.c Peter Zijlstra 2011-02-02 2802
> dd41f596 kernel/sched.c Ingo Molnar 2007-07-09 2803 mm = next->mm;
> dd41f596 kernel/sched.c Ingo Molnar 2007-07-09 2804 oldmm = prev->active_mm;
> 9226d125 kernel/sched.c Zachary Amsden 2007-02-13 2805 /*
> 9226d125 kernel/sched.c Zachary Amsden 2007-02-13 2806 * For paravirt, this is coupled with an exit in switch_to to
> 9226d125 kernel/sched.c Zachary Amsden 2007-02-13 2807 * combine the page table reload and the switch backend into
> 9226d125 kernel/sched.c Zachary Amsden 2007-02-13 2808 * one hypercall.
> 9226d125 kernel/sched.c Zachary Amsden 2007-02-13 2809 */
> 224101ed kernel/sched.c Jeremy Fitzhardinge 2009-02-18 2810 arch_start_context_switch(prev);
> 9226d125 kernel/sched.c Zachary Amsden 2007-02-13 2811
> 306e0604 kernel/sched/core.c Mathieu Desnoyers 2018-01-29 2812 /*
> 306e0604 kernel/sched/core.c Mathieu Desnoyers 2018-01-29 2813 * If mm is non-NULL, we pass through switch_mm(). If mm is
> 306e0604 kernel/sched/core.c Mathieu Desnoyers 2018-01-29 2814 * NULL, we will pass through mmdrop() in finish_task_switch().
> 306e0604 kernel/sched/core.c Mathieu Desnoyers 2018-01-29 2815 * Both of these contain the full memory barrier required by
> 306e0604 kernel/sched/core.c Mathieu Desnoyers 2018-01-29 2816 * membarrier after storing to rq->curr, before returning to
> 306e0604 kernel/sched/core.c Mathieu Desnoyers 2018-01-29 2817 * user-space.
> 306e0604 kernel/sched/core.c Mathieu Desnoyers 2018-01-29 2818 */
> 31915ab4 kernel/sched.c Heiko Carstens 2010-09-16 2819 if (!mm) {
> ^1da177e kernel/sched.c Linus Torvalds 2005-04-16 2820 next->active_mm = oldmm;
> f1f10076 kernel/sched/core.c Vegard Nossum 2017-02-27 2821 mmgrab(oldmm);
> ^1da177e kernel/sched.c Linus Torvalds 2005-04-16 2822 enter_lazy_tlb(oldmm, next);
> ^1da177e kernel/sched.c Linus Torvalds 2005-04-16 2823 } else
> f98db601 kernel/sched/core.c Andy Lutomirski 2016-04-26 2824 switch_mm_irqs_off(oldmm, mm, next);
> ^1da177e kernel/sched.c Linus Torvalds 2005-04-16 2825
> 31915ab4 kernel/sched.c Heiko Carstens 2010-09-16 2826 if (!prev->mm) {
> ^1da177e kernel/sched.c Linus Torvalds 2005-04-16 2827 prev->active_mm = NULL;
> ^1da177e kernel/sched.c Linus Torvalds 2005-04-16 2828 rq->prev_mm = oldmm;
> ^1da177e kernel/sched.c Linus Torvalds 2005-04-16 2829 }
> 92509b73 kernel/sched/core.c Matt Fleming 2016-09-21 2830
> cb42c9a3 kernel/sched/core.c Matt Fleming 2016-09-21 2831 rq->clock_update_flags &= ~(RQCF_ACT_SKIP|RQCF_REQ_SKIP);
> 92509b73 kernel/sched/core.c Matt Fleming 2016-09-21 2832
> 269d5992 kernel/sched/core.c Peter Zijlstra 2018-02-06 2833 prepare_lock_switch(rq, next, rf);
> ^1da177e kernel/sched.c Linus Torvalds 2005-04-16 2834
> ^1da177e kernel/sched.c Linus Torvalds 2005-04-16 2835 /* Here we just switch the register state and the stack. */
> ^1da177e kernel/sched.c Linus Torvalds 2005-04-16 @2836 switch_to(prev, next, prev);
> dd41f596 kernel/sched.c Ingo Molnar 2007-07-09 2837 barrier();
> dfa50b60 kernel/sched/core.c Oleg Nesterov 2014-10-09 2838
> dfa50b60 kernel/sched/core.c Oleg Nesterov 2014-10-09 2839 return finish_task_switch(prev);
> ^1da177e kernel/sched.c Linus Torvalds 2005-04-16 2840 }
> f711f609 kernel/sched.c Gautham R Shenoy 2009-04-14 2841
>
> :::::: The code at line 2836 was first introduced by commit
> :::::: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Linux-2.6.12-rc2
>
> :::::: TO: Linus Torvalds <torvalds@xxxxxxxxxxxxxxx>
> :::::: CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxx>
>
> ---
> 0-DAY kernel test infrastructure Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all Intel Corporation
>
--
~Randy