[bug report] mm: reduce noise in show_mem for lowmem allocations

[Dan Carpenter <dan.carpenter@xxxxxxxxxx>]

Hello Michal Hocko,

The patch e8fedfea3dea: "mm: reduce noise in show_mem for lowmem
allocations" from Aug 23, 2022, leads to the following Smatch static
checker warning:

	kernel/panic.c:190 panic_print_sys_info()
	warn: sleeping in atomic context

kernel/panic.c
    175 static void panic_print_sys_info(bool console_flush)
    176 {
    177         if (console_flush) {
    178                 if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG)
    179                         console_flush_on_panic(CONSOLE_REPLAY_ALL);
    180                 return;
    181         }
    182 
    183         if (panic_print & PANIC_PRINT_ALL_CPU_BT)
    184                 trigger_all_cpu_backtrace();
    185 
    186         if (panic_print & PANIC_PRINT_TASK_INFO)
    187                 show_state();
    188 
    189         if (panic_print & PANIC_PRINT_MEM_INFO)
--> 190                 show_mem(0, NULL, GFP_HIGHUSER_MOVABLE);
                                          ^^^^^^^^^^^^^^^^^^^^
This obviously seems very deliberate and a lot of weird stuff happens
during panic().  But the panic() function disables preemption so
shouldn't this be GFP_ATOMIC?  GFP_HIGHUSER_MOVABLE has __GFP_RECLAIM
and triggering swap during a panic seems bad.

    191 
    192         if (panic_print & PANIC_PRINT_TIMER_INFO)
    193                 sysrq_timer_list_show();
    194 
    195         if (panic_print & PANIC_PRINT_LOCK_INFO)
    196                 debug_show_all_locks();
    197 
    198         if (panic_print & PANIC_PRINT_FTRACE_INFO)
    199                 ftrace_dump(DUMP_ALL);
    200 }

regards,
dan carpenter