diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 983e5d3a0d271c387e24371ddc3fcd6e7110a27d..0b56666e6039b9d090cc01c014ccba2b2662be88 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -1153,3 +1153,14 @@ ENTRY(async_page_fault) jmp error_code END(async_page_fault) #endif + +ENTRY(rewind_stack_do_exit) + /* Prevent any naive code from trying to unwind to our caller. */ + xorl %ebp, %ebp + + movl PER_CPU_VAR(cpu_current_top_of_stack), %esi + leal -TOP_OF_KERNEL_STACK_PADDING-PTREGS_SIZE(%esi), %esp + + call do_exit +1: jmp 1b +END(rewind_stack_do_exit) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 9ee0da1807edff462536e3628e1db217bb835cd8..b846875aeea6792ce4a0c359f7635112f27e84d5 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1423,3 +1423,14 @@ ENTRY(ignore_sysret) mov $-ENOSYS, %eax sysret END(ignore_sysret) + +ENTRY(rewind_stack_do_exit) + /* Prevent any naive code from trying to unwind to our caller. */ + xorl %ebp, %ebp + + movq PER_CPU_VAR(cpu_current_top_of_stack), %rax + leaq -TOP_OF_KERNEL_STACK_PADDING-PTREGS_SIZE(%rax), %rsp + + call do_exit +1: jmp 1b +END(rewind_stack_do_exit) diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index cc88e25d73e9ef80bb056154250ba424091cf2b8..de8242d8bb61939b53e2ef326ececeff51b18d02 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -234,6 +234,8 @@ unsigned long oops_begin(void) EXPORT_SYMBOL_GPL(oops_begin); NOKPROBE_SYMBOL(oops_begin); +void __noreturn rewind_stack_do_exit(int signr); + void oops_end(unsigned long flags, struct pt_regs *regs, int signr) { if (regs && kexec_should_crash(current)) @@ -255,7 +257,13 @@ void oops_end(unsigned long flags, struct pt_regs *regs, int signr) panic("Fatal exception in interrupt"); if (panic_on_oops) panic("Fatal exception"); - do_exit(signr); + + /* + * We're not going to return, but we might be on an IST stack or + * have very little stack space left. Rewind the stack and kill + * the task. + */ + rewind_stack_do_exit(signr); } NOKPROBE_SYMBOL(oops_end);