From 33bbc3065414722065a20cbdbeaf352173e72f39 Mon Sep 17 00:00:00 2001 From: Thomas Meyer Date: Sat, 28 Mar 2015 09:59:46 +0100 Subject: [PATCH] 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: Thomas Meyer Signed-off-by: Richard Weinberger --- arch/um/include/shared/as-layout.h | 1 + arch/um/kernel/um_arch.c | 15 ++++++++++----- arch/um/os-Linux/skas/process.c | 2 +- 3 files changed, 12 insertions(+), 6 deletions(-) diff --git a/arch/um/include/shared/as-layout.h b/arch/um/include/shared/as-layout.h index 41c8c77..ca1843e 100644 --- a/arch/um/include/shared/as-layout.h +++ b/arch/um/include/shared/as-layout.h @@ -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 *); diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c index 926ecdc..07f798f 100644 --- a/arch/um/kernel/um_arch.c +++ b/arch/um/kernel/um_arch.c @@ -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(); diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c index 50ebeae..7a97775 100644 --- a/arch/um/os-Linux/skas/process.c +++ b/arch/um/os-Linux/skas/process.c @@ -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; -- 2.7.4