> But that happens before do_IRQ is called, so what is the do_IRQ call > chain doing on this stack given that we've already supposed to have > switched to the interrupt stack before do_IRQ is called? Not sure I understand the question. The pt_regs are on the original stack (but they are quite small), all the rest is on the new stack. ISTs are not used for interrupts, only for some special exceptions. do_IRQ doesn't switch any stacks on 64bit. -Andi -- ak@xxxxxxxxxxxxxxx -- Speaking for myself only. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>