Thanks to all the recent x86 entry code refactoring, most tasks' kernel stacks start at the same offset right above their saved pt_regs, regardless of which syscall was used to enter the kernel. That creates a nice convention which makes it straightforward to identify the end of the stack, which can be useful for stack walking code which needs to verify the stack is sane.
However, CPU idle "swapper" tasks don't follow that convention. Fix that by starting their stack at a sizeof(pt_regs) offset from the end of the stack page. Signed-off-by: Josh Poimboeuf <[email protected]> --- arch/x86/kernel/head_64.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index c910c27..e33081d 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -326,7 +326,7 @@ ENDPROC(start_cpu0) GLOBAL(initial_gs) .quad INIT_PER_CPU_VAR(irq_stack_union) GLOBAL(initial_stack) - .quad init_thread_union+THREAD_SIZE-8 + .quad init_thread_union + THREAD_SIZE - SIZEOF_PTREGS __FINITDATA bad_address: -- 2.7.4
