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authorJosh Poimboeuf <jpoimboe@redhat.com>2016-09-14 21:07:42 -0500
committerIngo Molnar <mingo@kernel.org>2016-09-15 08:13:15 +0200
commitcb76c93982404273d746f3ccd5085b47689099a8 (patch)
tree95103a60e29ad190e4ee9ef3818f97825eab936f /arch/x86/kernel/dumpstack_64.c
parent9c00390757fd9f5851f7973b2f0e1e41550bb3b8 (diff)
downloadlinux-cb76c93982404273d746f3ccd5085b47689099a8.tar.bz2
x86/dumpstack: Add get_stack_info() interface
valid_stack_ptr() is buggy: it assumes that all stacks are of size THREAD_SIZE, which is not true for exception stacks. So the walk_stack() callbacks will need to know the location of the beginning of the stack as well as the end. Another issue is that in general the various features of a stack (type, size, next stack pointer, description string) are scattered around in various places throughout the stack dump code. Encapsulate all that information in a single place with a new stack_info struct and a get_stack_info() interface. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Byungchul Park <byungchul.park@lge.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nilay Vaish <nilayvaish@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/8164dd0db96b7e6a279fa17ae5e6dc375eecb4a9.1473905218.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/dumpstack_64.c')
-rw-r--r--arch/x86/kernel/dumpstack_64.c169
1 files changed, 91 insertions, 78 deletions
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 904fb46d7d65..41813abc7380 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -28,76 +28,109 @@ static unsigned long exception_stack_sizes[N_EXCEPTION_STACKS] = {
[DEBUG_STACK - 1] = DEBUG_STKSZ
};
-static unsigned long *in_exception_stack(unsigned long stack, unsigned *usedp,
- char **idp)
+void stack_type_str(enum stack_type type, const char **begin, const char **end)
{
- unsigned long begin, end;
+ BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
+
+ switch (type) {
+ case STACK_TYPE_IRQ:
+ *begin = "IRQ";
+ *end = "EOI";
+ break;
+ case STACK_TYPE_EXCEPTION ... STACK_TYPE_EXCEPTION_LAST:
+ *begin = exception_stack_names[type - STACK_TYPE_EXCEPTION];
+ *end = "EOE";
+ break;
+ default:
+ *begin = NULL;
+ *end = NULL;
+ }
+}
+
+static bool in_exception_stack(unsigned long *stack, struct stack_info *info,
+ unsigned long *visit_mask)
+{
+ unsigned long *begin, *end;
+ struct pt_regs *regs;
unsigned k;
BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
for (k = 0; k < N_EXCEPTION_STACKS; k++) {
- end = raw_cpu_ptr(&orig_ist)->ist[k];
- begin = end - exception_stack_sizes[k];
+ end = (unsigned long *)raw_cpu_ptr(&orig_ist)->ist[k];
+ begin = end - (exception_stack_sizes[k] / sizeof(long));
+ regs = (struct pt_regs *)end - 1;
if (stack < begin || stack >= end)
continue;
/*
- * Make sure we only iterate through an exception stack once.
- * If it comes up for the second time then there's something
- * wrong going on - just break and return NULL:
+ * Make sure we don't iterate through an exception stack more
+ * than once. If it comes up a second time then there's
+ * something wrong going on - just break out and report an
+ * unknown stack type.
*/
- if (*usedp & (1U << k))
+ if (*visit_mask & (1U << k))
break;
- *usedp |= 1U << k;
+ *visit_mask |= 1U << k;
- *idp = exception_stack_names[k];
- return (unsigned long *)end;
+ info->type = STACK_TYPE_EXCEPTION + k;
+ info->begin = begin;
+ info->end = end;
+ info->next_sp = (unsigned long *)regs->sp;
+
+ return true;
}
- return NULL;
+ return false;
}
-static inline int
-in_irq_stack(unsigned long *stack, unsigned long *irq_stack,
- unsigned long *irq_stack_end)
+static bool in_irq_stack(unsigned long *stack, struct stack_info *info)
{
- return (stack >= irq_stack && stack < irq_stack_end);
-}
+ unsigned long *end = (unsigned long *)this_cpu_read(irq_stack_ptr);
+ unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long));
-enum stack_type {
- STACK_IS_UNKNOWN,
- STACK_IS_NORMAL,
- STACK_IS_EXCEPTION,
- STACK_IS_IRQ,
-};
+ if (stack < begin || stack >= end)
+ return false;
+
+ info->type = STACK_TYPE_IRQ;
+ info->begin = begin;
+ info->end = end;
+
+ /*
+ * The next stack pointer is the first thing pushed by the entry code
+ * after switching to the irq stack.
+ */
+ info->next_sp = (unsigned long *)*(end - 1);
+
+ return true;
+}
-static enum stack_type
-analyze_stack(struct task_struct *task, unsigned long *stack,
- unsigned long **stack_end, unsigned long *irq_stack,
- unsigned *used, char **id)
+int get_stack_info(unsigned long *stack, struct task_struct *task,
+ struct stack_info *info, unsigned long *visit_mask)
{
- unsigned long addr;
+ if (!stack)
+ goto unknown;
- addr = ((unsigned long)stack & (~(THREAD_SIZE - 1)));
- if ((unsigned long)task_stack_page(task) == addr)
- return STACK_IS_NORMAL;
+ task = task ? : current;
+
+ if (in_task_stack(stack, task, info))
+ return 0;
- *stack_end = in_exception_stack((unsigned long)stack, used, id);
- if (*stack_end)
- return STACK_IS_EXCEPTION;
+ if (task != current)
+ goto unknown;
- if (!irq_stack)
- return STACK_IS_NORMAL;
+ if (in_exception_stack(stack, info, visit_mask))
+ return 0;
- *stack_end = irq_stack;
- irq_stack -= (IRQ_STACK_SIZE / sizeof(long));
+ if (in_irq_stack(stack, info))
+ return 0;
- if (in_irq_stack(stack, irq_stack, *stack_end))
- return STACK_IS_IRQ;
+ return 0;
- return STACK_IS_UNKNOWN;
+unknown:
+ info->type = STACK_TYPE_UNKNOWN;
+ return -EINVAL;
}
/*
@@ -111,8 +144,8 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, unsigned long bp,
const struct stacktrace_ops *ops, void *data)
{
- unsigned long *irq_stack = (unsigned long *)this_cpu_read(irq_stack_ptr);
- unsigned used = 0;
+ unsigned long visit_mask = 0;
+ struct stack_info info;
int graph = 0;
int done = 0;
@@ -126,57 +159,37 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
* exceptions
*/
while (!done) {
- unsigned long *stack_end;
- enum stack_type stype;
- char *id;
+ const char *begin_str, *end_str;
- stype = analyze_stack(task, stack, &stack_end, irq_stack, &used,
- &id);
+ get_stack_info(stack, task, &info, &visit_mask);
/* Default finish unless specified to continue */
done = 1;
- switch (stype) {
+ switch (info.type) {
/* Break out early if we are on the thread stack */
- case STACK_IS_NORMAL:
+ case STACK_TYPE_TASK:
break;
- case STACK_IS_EXCEPTION:
+ case STACK_TYPE_IRQ:
+ case STACK_TYPE_EXCEPTION ... STACK_TYPE_EXCEPTION_LAST:
+
+ stack_type_str(info.type, &begin_str, &end_str);
- if (ops->stack(data, id) < 0)
+ if (ops->stack(data, begin_str) < 0)
break;
bp = ops->walk_stack(task, stack, bp, ops,
- data, stack_end, &graph);
- ops->stack(data, "EOE");
- /*
- * We link to the next stack via the
- * second-to-last pointer (index -2 to end) in the
- * exception stack:
- */
- stack = (unsigned long *) stack_end[-2];
- done = 0;
- break;
+ data, &info, &graph);
- case STACK_IS_IRQ:
+ ops->stack(data, end_str);
- if (ops->stack(data, "IRQ") < 0)
- break;
- bp = ops->walk_stack(task, stack, bp,
- ops, data, stack_end, &graph);
- /*
- * We link to the next stack (which would be
- * the process stack normally) the last
- * pointer (index -1 to end) in the IRQ stack:
- */
- stack = (unsigned long *) (stack_end[-1]);
- irq_stack = NULL;
- ops->stack(data, "EOI");
+ stack = info.next_sp;
done = 0;
break;
- case STACK_IS_UNKNOWN:
+ default:
ops->stack(data, "UNK");
break;
}
@@ -185,7 +198,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
/*
* This handles the process stack:
*/
- bp = ops->walk_stack(task, stack, bp, ops, data, NULL, &graph);
+ bp = ops->walk_stack(task, stack, bp, ops, data, &info, &graph);
}
EXPORT_SYMBOL(dump_trace);