Lines Matching refs:the
4 Most of the text from Keith Owens, hacked by AK
11 zombie. While the thread is in user space the kernel stack is empty
12 except for the thread_info structure at the bottom.
14 In addition to the per thread stacks, there are specialized stacks
15 associated with each CPU. These stacks are only used while the kernel
16 is in control on that CPU; when a CPU returns to user space the
21 Used for external hardware interrupts. If this is the first external
22 hardware interrupt (i.e. not a nested hardware interrupt) then the
23 kernel switches from the current task to the interrupt stack. Like
24 the split thread and interrupt stacks on i386, this gives more room
25 for kernel interrupt processing without having to increase the size
30 Switching to the kernel interrupt stack is done by software based on a
34 x86_64 also has a feature which is not available on i386, the ability
37 events on x86_64. This feature is called the Interrupt Stack Table
39 index into the Task State Segment (TSS). The IST entries in the TSS
42 An IST is selected by a non-zero value in the IST field of an
43 interrupt-gate descriptor. When an interrupt occurs and the hardware
44 loads such a descriptor, the hardware automatically sets the new stack
45 pointer based on the IST value, then invokes the interrupt handler. If
46 the interrupt came from user mode, then the interrupt handler prologue
47 will switch back to the per-thread stack. If software wants to allow
48 nested IST interrupts then the handler must adjust the IST values on
49 entry to and exit from the interrupt handler. (This is occasionally
54 NMI. arch/x86_64/kernel/entry.S::paranoidentry adjusts the stack
56 IST events with the same code to be nested. However in most cases, the
57 stack size allocated to an IST assumes no nesting for the same code.
58 If that assumption is ever broken then the stacks will become corrupt.
67 when the kernel is very confused (e.g. kernel stack pointer corrupt).
68 Using a separate stack allows the kernel to recover from it well enough
75 NMI can be delivered at any time, including when the kernel is in the
77 assumptions about the previous state of the kernel stack.
86 avoids making assumptions about the previous state of the kernel
93 MCE can be delivered at any time, including when the kernel is in the
95 assumptions about the previous state of the kernel stack.
97 For more details see the Intel IA32 or AMD AMD64 architecture manuals.
103 The question about the '?' preceding function names in an x86 stacktrace
104 keeps popping up, here's an indepth explanation. It helps if the reader
105 stares at print_context_stack() and the whole machinery in and around
110 We always scan the full kernel stack for return addresses stored on
111 the kernel stack(s) [*], from stack top to stack bottom, and print out
114 If it fits into the frame pointer chain, we print it without a question
115 mark, knowing that it's part of the real backtrace.
117 If the address does not fit into our expected frame pointer chain we
120 - either the address is not part of the call chain: it's just stale
121 values on the kernel stack, from earlier function calls. This is
122 the common case.
124 - or it is part of the call chain, but the frame pointer was not set
125 up properly within the function, so we don't recognize it.
127 This way we will always print out the real call chain (plus a few more
128 entries), regardless of whether the frame pointer was set up correctly
129 or not - but in most cases we'll get the call chain right as well. The
134 information: we always strive to print _all_ addresses on the stack(s)
136 we still print out the real call chain as well - just with more question
140 the right order, and try to cross from one stack into another
141 reconstructing the call chain. This works most of the time.