Re: [PATCH v2 1/4] panic: Add panic_in_progress helper

[Stephen Brennan <stephen.s.brennan@oracle.com>]

On 1/27/22 06:34, Petr Mladek wrote:
> On Wed 2022-01-26 15:02:33, Stephen Brennan wrote:
>> This helper will be used in printk code to avoid deadlocks during
>> panic().
>>
>> Suggested-by: Petr Mladek <pmladek@suse.com>
>> Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
> 
> Reviewed-by: Petr Mladek <pmladek@suse.com>
> 
> Best Regards,
> Petr

Hi Petr,

Thanks for the review, however over the night I received two kernel test 
robot emails. One indicating a new build error caused by this change on 
m68k arch, and the other adding a new warning on riscv. From what I can 
tell, the issues are circular dependencies in #includes. So it may be 
better to either return to the macro, or move this static inline down to 
kernel/printk/printk.c. I think moving it into kernel/printk/printk.c 
makes most sense given that the macro requires the correct #includes anyway.

Thanks,
Stephen

------------- m68k

    In file included from include/asm-generic/preempt.h:5,
                     from ./arch/m68k/include/generated/asm/preempt.h:1,
                     from include/linux/preempt.h:78,
                     from arch/m68k/include/asm/irqflags.h:6,
                     from include/linux/irqflags.h:16,
                     from arch/m68k/include/asm/atomic.h:6,
                     from include/linux/atomic.h:7,
                     from include/linux/panic.h:7,
                     from include/asm-generic/bug.h:21,
                     from arch/m68k/include/asm/bug.h:32,
                     from include/linux/bug.h:5,
                     from include/linux/page-flags.h:10,
                     from kernel/bounds.c:10:
    include/linux/thread_info.h: In function 'copy_overflow':
 >> include/linux/thread_info.h:214:9: error: implicit declaration of 
function 'WARN' [-Werror=implicit-function-declaration]
      214 |         WARN(1, "Buffer overflow detected (%d < %lu)!\n", 
size, count);
          |         ^~~~
    include/linux/thread_info.h: In function 'check_copy_size':
 >> include/linux/thread_info.h:230:13: error: implicit declaration of 
function 'WARN_ON_ONCE' [-Werror=implicit-function-declaration]
      230 |         if (WARN_ON_ONCE(bytes > INT_MAX))
          |             ^~~~~~~~~~~~
    cc1: some warnings being treated as errors
    make[2]: *** [scripts/Makefile.build:121: kernel/bounds.s] Error 1
    make[2]: Target '__build' not remade because of errors.
    make[1]: *** [Makefile:1191: prepare0] Error 2
    make[1]: Target 'prepare' not remade because of errors.
    make: *** [Makefile:219: __sub-make] Error 2
    make: Target 'prepare' not remade because of errors.

----------------- riscv:

    In file included from arch/riscv/include/asm/atomic.h:19,
                     from include/linux/atomic.h:7,
                     from include/linux/panic.h:7,
                     from include/asm-generic/bug.h:21,
                     from arch/riscv/include/asm/bug.h:83,
                     from include/linux/bug.h:5,
                     from include/linux/page-flags.h:10,
                     from kernel/bounds.c:10:
    arch/riscv/include/asm/atomic.h: In function 'arch_atomic_xchg_relaxed':
 >> arch/riscv/include/asm/cmpxchg.h:35:17: error: implicit declaration 
of function 'BUILD_BUG' [-Werror=implicit-function-declaration]
       35 |                 BUILD_BUG(); 
             \
          |                 ^~~~~~~~~
    arch/riscv/include/asm/atomic.h:249:16: note: in expansion of macro 
'__xchg_relaxed'
      249 |         return __xchg_relaxed(&(v->counter), n, size); 
             \
          |                ^~~~~~~~~~~~~~
    arch/riscv/include/asm/atomic.h:295:9: note: in expansion of macro 
'ATOMIC_OP'
      295 |         ATOMIC_OP(int,   , 4) 
             \
          |         ^~~~~~~~~
    arch/riscv/include/asm/atomic.h:299:1: note: in expansion of macro 
'ATOMIC_OPS'
      299 | ATOMIC_OPS()
          | ^~~~~~~~~~
    cc1: some warnings being treated as errors
    make[2]: *** [scripts/Makefile.build:121: kernel/bounds.s] Error 1
    make[2]: Target '__build' not remade because of errors.
    make[1]: *** [Makefile:1191: prepare0] Error 2
    make[1]: Target 'prepare' not remade because of errors.
    make: *** [Makefile:219: __sub-make] Error 2
    make: Target 'prepare' not remade because of errors.