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Commit 33bbc306 authored by Thomas Meyer's avatar Thomas Meyer Committed by Richard Weinberger
Browse files

um: Move uml_postsetup in the init_thread stack 



atomic_notifier_chain_register() and uml_postsetup() do call kernel code
that rely on the "current" kernel macro and a valid task_struct resp.
thread_info struct. Give those functions a valid stack by moving
uml_postsetup() in the init_thread stack. This moves enables a panic()
call in this early code to generate a valid stacktrace, instead of
crashing.
E.g. when an UML kernel is started with an initrd but too few physical
memory the panic() call get's actually processed.

Signed-off-by: default avatarThomas Meyer <thomas@m3y3r.de>
Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
parent 04a41849

arch/um/include/shared/as-layout.h

+1 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ extern unsigned long brk_start; 
extern unsigned long host_task_size;



extern int linux_main(int argc, char **argv);

extern void uml_finishsetup(void);



struct siginfo;

extern void (*sig_info[])(int, struct siginfo *si, struct uml_pt_regs *);

arch/um/kernel/um_arch.c

+10 −5
Original line number Diff line number Diff line
@@ -226,6 +226,16 @@ static struct notifier_block panic_exit_notifier = { 
	.priority 		= 0

};



void uml_finishsetup(void)

{

	atomic_notifier_chain_register(&panic_notifier_list,

				       &panic_exit_notifier);



	uml_postsetup();



	new_thread_handler();

}



/* Set during early boot */

unsigned long task_size;

EXPORT_SYMBOL(task_size);
@@ -326,11 +336,6 @@ int __init linux_main(int argc, char **argv) 
		printf("Kernel virtual memory size shrunk to %lu bytes\n",

		       virtmem_size);



	atomic_notifier_chain_register(&panic_notifier_list,

				       &panic_exit_notifier);



	uml_postsetup();



	stack_protections((unsigned long) &init_thread_info);

	os_flush_stdout();

arch/um/os-Linux/skas/process.c

+1 −1
Original line number Diff line number Diff line
@@ -586,7 +586,7 @@ int start_idle_thread(void *stack, jmp_buf *switch_buf) 
	n = setjmp(initial_jmpbuf);

	switch (n) {

	case INIT_JMP_NEW_THREAD:

		(*switch_buf)[0].JB_IP = (unsigned long) new_thread_handler;

		(*switch_buf)[0].JB_IP = (unsigned long) uml_finishsetup;

		(*switch_buf)[0].JB_SP = (unsigned long) stack +

			UM_THREAD_SIZE - sizeof(void *);

		break;