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From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Jiri Kosina <jikos@kernel.org>, Jessica Yu <jeyu@redhat.com>,
	Miroslav Benes <mbenes@suse.cz>
Cc: linux-kernel@vger.kernel.org, live-patching@vger.kernel.org,
	Vojtech Pavlik <vojtech@suse.com>
Subject: [RFC PATCH v1.9 06/14] x86: add error handling to dump_trace()
Date: Fri, 25 Mar 2016 14:34:53 -0500	[thread overview]
Message-ID: <6b02b97ca6dc29008b7d2cc91ca707d51fe58466.1458933243.git.jpoimboe@redhat.com> (raw)
In-Reply-To: <cover.1458933243.git.jpoimboe@redhat.com>

In preparation for being able to determine whether a given stack trace
is reliable, allow the stacktrace_ops functions to propagate errors to
dump_trace().

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 arch/x86/include/asm/stacktrace.h | 36 +++++++++++++++-----------
 arch/x86/kernel/dumpstack.c       | 31 +++++++++++------------
 arch/x86/kernel/dumpstack_32.c    | 22 ++++++++++------
 arch/x86/kernel/dumpstack_64.c    | 53 ++++++++++++++++++++++++++-------------
 4 files changed, 87 insertions(+), 55 deletions(-)

diff --git a/arch/x86/include/asm/stacktrace.h b/arch/x86/include/asm/stacktrace.h
index 7c247e7..a64523f3 100644
--- a/arch/x86/include/asm/stacktrace.h
+++ b/arch/x86/include/asm/stacktrace.h
@@ -14,26 +14,32 @@ extern int kstack_depth_to_print;
 struct thread_info;
 struct stacktrace_ops;
 
-typedef unsigned long (*walk_stack_t)(struct thread_info *tinfo,
-				      unsigned long *stack,
-				      unsigned long bp,
-				      const struct stacktrace_ops *ops,
-				      void *data,
-				      unsigned long *end,
-				      int *graph);
-
-extern unsigned long
+typedef int (*walk_stack_t)(struct thread_info *tinfo,
+			    unsigned long *stack,
+			    unsigned long *bp,
+			    const struct stacktrace_ops *ops,
+			    void *data,
+			    unsigned long *end,
+			    int *graph);
+
+extern int
 print_context_stack(struct thread_info *tinfo,
-		    unsigned long *stack, unsigned long bp,
+		    unsigned long *stack, unsigned long *bp,
 		    const struct stacktrace_ops *ops, void *data,
 		    unsigned long *end, int *graph);
 
-extern unsigned long
+extern int
 print_context_stack_bp(struct thread_info *tinfo,
-		       unsigned long *stack, unsigned long bp,
+		       unsigned long *stack, unsigned long *bp,
 		       const struct stacktrace_ops *ops, void *data,
 		       unsigned long *end, int *graph);
 
+extern int
+print_context_stack_reliable(struct thread_info *tinfo,
+			     unsigned long *stack, unsigned long *bp,
+			     const struct stacktrace_ops *ops, void *data,
+			     unsigned long *end, int *graph);
+
 /* Generic stack tracer with callbacks */
 
 struct stacktrace_ops {
@@ -43,9 +49,9 @@ struct stacktrace_ops {
 	walk_stack_t	walk_stack;
 };
 
-void dump_trace(struct task_struct *tsk, struct pt_regs *regs,
-		unsigned long *stack, unsigned long bp,
-		const struct stacktrace_ops *ops, void *data);
+int dump_trace(struct task_struct *tsk, struct pt_regs *regs,
+	       unsigned long *stack, unsigned long bp,
+	       const struct stacktrace_ops *ops, void *data);
 
 #ifdef CONFIG_X86_32
 #define STACKSLOTS_PER_LINE 8
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 8efa57a..3b10518 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -92,23 +92,22 @@ static inline int valid_stack_ptr(struct thread_info *tinfo,
 	return p > t && p < t + THREAD_SIZE - size;
 }
 
-unsigned long
-print_context_stack(struct thread_info *tinfo,
-		unsigned long *stack, unsigned long bp,
-		const struct stacktrace_ops *ops, void *data,
-		unsigned long *end, int *graph)
+int print_context_stack(struct thread_info *tinfo,
+			unsigned long *stack, unsigned long *bp,
+			const struct stacktrace_ops *ops, void *data,
+			unsigned long *end, int *graph)
 {
-	struct stack_frame *frame = (struct stack_frame *)bp;
+	struct stack_frame *frame = (struct stack_frame *)*bp;
 
 	while (valid_stack_ptr(tinfo, stack, sizeof(*stack), end)) {
 		unsigned long addr;
 
 		addr = *stack;
 		if (__kernel_text_address(addr)) {
-			if ((unsigned long) stack == bp + sizeof(long)) {
+			if ((unsigned long) stack == *bp + sizeof(long)) {
 				ops->address(data, addr, 1);
 				frame = frame->next_frame;
-				bp = (unsigned long) frame;
+				*bp = (unsigned long) frame;
 			} else {
 				ops->address(data, addr, 0);
 			}
@@ -116,17 +115,16 @@ print_context_stack(struct thread_info *tinfo,
 		}
 		stack++;
 	}
-	return bp;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(print_context_stack);
 
-unsigned long
-print_context_stack_bp(struct thread_info *tinfo,
-		       unsigned long *stack, unsigned long bp,
-		       const struct stacktrace_ops *ops, void *data,
-		       unsigned long *end, int *graph)
+int print_context_stack_bp(struct thread_info *tinfo,
+			   unsigned long *stack, unsigned long *bp,
+			   const struct stacktrace_ops *ops, void *data,
+			   unsigned long *end, int *graph)
 {
-	struct stack_frame *frame = (struct stack_frame *)bp;
+	struct stack_frame *frame = (struct stack_frame *)*bp;
 	unsigned long *ret_addr = &frame->return_address;
 
 	while (valid_stack_ptr(tinfo, ret_addr, sizeof(*ret_addr), end)) {
@@ -142,7 +140,8 @@ print_context_stack_bp(struct thread_info *tinfo,
 		print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
 	}
 
-	return (unsigned long)frame;
+	*bp = (unsigned long)frame;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(print_context_stack_bp);
 
diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index 464ffd6..e710bab 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -38,13 +38,14 @@ static void *is_softirq_stack(unsigned long *stack, int cpu)
 	return is_irq_stack(stack, irq);
 }
 
-void dump_trace(struct task_struct *task, struct pt_regs *regs,
-		unsigned long *stack, unsigned long bp,
-		const struct stacktrace_ops *ops, void *data)
+int dump_trace(struct task_struct *task, struct pt_regs *regs,
+	       unsigned long *stack, unsigned long bp,
+	       const struct stacktrace_ops *ops, void *data)
 {
 	const unsigned cpu = get_cpu();
 	int graph = 0;
 	u32 *prev_esp;
+	int ret;
 
 	if (!task)
 		task = current;
@@ -69,8 +70,10 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 			end_stack = is_softirq_stack(stack, cpu);
 
 		context = task_thread_info(task);
-		bp = ops->walk_stack(context, stack, bp, ops, data,
-				     end_stack, &graph);
+		ret = ops->walk_stack(context, stack, &bp, ops, data,
+				      end_stack, &graph);
+		if (ret)
+			goto out;
 
 		/* Stop if not on irq stack */
 		if (!end_stack)
@@ -82,11 +85,16 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 		if (!stack)
 			break;
 
-		if (ops->stack(data, "IRQ") < 0)
-			break;
+		ret = ops->stack(data, "IRQ");
+		if (ret)
+			goto out;
+
 		touch_nmi_watchdog();
 	}
+
+out:
 	put_cpu();
+	return ret;
 }
 EXPORT_SYMBOL(dump_trace);
 
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 5f1c626..0c810ba 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -148,9 +148,9 @@ analyze_stack(int cpu, struct task_struct *task, unsigned long *stack,
  * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
  */
 
-void dump_trace(struct task_struct *task, struct pt_regs *regs,
-		unsigned long *stack, unsigned long bp,
-		const struct stacktrace_ops *ops, void *data)
+int dump_trace(struct task_struct *task, struct pt_regs *regs,
+	       unsigned long *stack, unsigned long bp,
+	       const struct stacktrace_ops *ops, void *data)
 {
 	const unsigned cpu = get_cpu();
 	struct thread_info *tinfo;
@@ -159,6 +159,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 	unsigned used = 0;
 	int graph = 0;
 	int done = 0;
+	int ret;
 
 	if (!task)
 		task = current;
@@ -198,13 +199,18 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 			break;
 
 		case STACK_IS_EXCEPTION:
-
-			if (ops->stack(data, id) < 0)
-				break;
-
-			bp = ops->walk_stack(tinfo, stack, bp, ops,
-					     data, stack_end, &graph);
-			ops->stack(data, "<EOE>");
+			ret = ops->stack(data, id);
+			if (ret)
+				goto out;
+
+			ret = ops->walk_stack(tinfo, stack, &bp, ops, data,
+					      stack_end, &graph);
+			if (ret)
+				goto out;
+
+			ret = ops->stack(data, "<EOE>");
+			if (ret)
+				goto out;
 			/*
 			 * We link to the next stack via the
 			 * second-to-last pointer (index -2 to end) in the
@@ -215,11 +221,15 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 			break;
 
 		case STACK_IS_IRQ:
+			ret = ops->stack(data, "IRQ");
+			if (ret)
+				goto out;
+
+			ret = ops->walk_stack(tinfo, stack, &bp, ops, data,
+					      stack_end, &graph);
+			if (ret)
+				goto out;
 
-			if (ops->stack(data, "IRQ") < 0)
-				break;
-			bp = ops->walk_stack(tinfo, stack, bp,
-				     ops, data, stack_end, &graph);
 			/*
 			 * We link to the next stack (which would be
 			 * the process stack normally) the last
@@ -227,12 +237,18 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 			 */
 			stack = (unsigned long *) (stack_end[-1]);
 			irq_stack = NULL;
-			ops->stack(data, "EOI");
+
+			ret = ops->stack(data, "EOI");
+			if (ret)
+				goto out;
+
 			done = 0;
 			break;
 
 		case STACK_IS_UNKNOWN:
-			ops->stack(data, "UNK");
+			ret = ops->stack(data, "UNK");
+			if (ret)
+				goto out;
 			break;
 		}
 	}
@@ -240,8 +256,11 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 	/*
 	 * This handles the process stack:
 	 */
-	bp = ops->walk_stack(tinfo, stack, bp, ops, data, NULL, &graph);
+	ret = ops->walk_stack(tinfo, stack, &bp, ops, data, NULL, &graph);
+
+out:
 	put_cpu();
+	return ret;
 }
 EXPORT_SYMBOL(dump_trace);
 
-- 
2.4.3

  parent reply	other threads:[~2016-03-25 19:36 UTC|newest]

Thread overview: 89+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-25 19:34 [RFC PATCH v1.9 00/14] livepatch: hybrid consistency model Josh Poimboeuf
2016-03-25 19:34 ` [RFC PATCH v1.9 01/14] x86/asm/head: cleanup initial stack variable Josh Poimboeuf
2016-03-25 19:34 ` [RFC PATCH v1.9 02/14] x86/asm/head: use a common function for starting CPUs Josh Poimboeuf
2016-03-25 19:34 ` [RFC PATCH v1.9 03/14] x86/asm/head: standardize the bottom of the stack for idle tasks Josh Poimboeuf
2016-03-25 19:34 ` [RFC PATCH v1.9 04/14] x86: move _stext marker before head code Josh Poimboeuf
2016-03-25 19:34 ` [RFC PATCH v1.9 05/14] sched: horrible way to detect whether a task has been preempted Josh Poimboeuf
2016-04-06 13:06   ` Petr Mladek
2016-04-06 16:33     ` Josh Poimboeuf
2016-04-07  9:47       ` Petr Mladek
2016-04-07 14:34         ` Josh Poimboeuf
2016-04-08  8:07           ` Petr Mladek
2016-04-08 14:34             ` Josh Poimboeuf
2016-04-07 21:15   ` Jessica Yu
2016-04-07 21:37     ` Jiri Kosina
2016-04-07 22:35       ` Josh Poimboeuf
2016-04-07 22:53         ` Jiri Kosina
2016-04-07 23:15       ` Jessica Yu
2016-04-08  7:05         ` Jiri Kosina
2016-04-08  8:03           ` Petr Mladek
2016-04-08 14:31             ` Josh Poimboeuf
2016-04-11  8:38               ` Petr Mladek
2016-03-25 19:34 ` Josh Poimboeuf [this message]
2016-03-25 19:34 ` [RFC PATCH v1.9 07/14] x86/stacktrace: add function for detecting reliable stack traces Josh Poimboeuf
2016-03-31 13:03   ` Miroslav Benes
2016-04-04 17:54     ` Josh Poimboeuf
2016-04-11 14:16       ` Jiri Slaby
2016-04-12 15:56         ` Josh Poimboeuf
2016-06-09  8:31           ` Jiri Slaby
2016-06-13 21:58             ` Josh Poimboeuf
2016-12-01 20:28               ` Jiri Slaby
2016-12-01 20:59                 ` Josh Poimboeuf
2017-01-17 13:08                   ` Jiri Slaby
2016-04-04 15:55   ` Petr Mladek
2016-04-04 17:58     ` Josh Poimboeuf
2016-04-07 11:55   ` Petr Mladek
2016-04-07 14:46     ` Josh Poimboeuf
2016-04-08  8:24       ` Petr Mladek
2016-04-11  3:29   ` Jessica Yu
2016-03-25 19:34 ` [RFC PATCH v1.9 08/14] livepatch: separate enabled and patched states Josh Poimboeuf
2016-04-11  3:31   ` Jessica Yu
2016-04-12 14:44   ` [RFC PATCH v1.9 08/14] " Chris J Arges
2016-04-12 17:16     ` Josh Poimboeuf
2016-04-12 17:35       ` Chris J Arges
2016-04-12 18:25         ` Josh Poimboeuf
2016-03-25 19:34 ` [RFC PATCH v1.9 09/14] livepatch: remove unnecessary object loaded check Josh Poimboeuf
2016-03-25 19:34 ` [RFC PATCH v1.9 10/14] livepatch: move patching functions into patch.c Josh Poimboeuf
2016-03-25 19:34 ` [RFC PATCH v1.9 11/14] livepatch: store function sizes Josh Poimboeuf
2016-03-25 19:34 ` [RFC PATCH v1.9 12/14] livepatch: create per-task consistency model Josh Poimboeuf
2016-03-31 13:12   ` Miroslav Benes
2016-04-04 18:21     ` Josh Poimboeuf
2016-04-04 18:27       ` Vojtech Pavlik
2016-04-04 18:33         ` Josh Poimboeuf
2016-04-05 11:36           ` Vojtech Pavlik
2016-04-05 13:53             ` Josh Poimboeuf
2016-04-05 17:32   ` Minfei Huang
2016-04-05 21:17     ` Josh Poimboeuf
2016-04-14  9:25   ` Miroslav Benes
2016-04-14 16:39     ` Josh Poimboeuf
2016-04-15  9:17       ` Miroslav Benes
2016-03-25 19:35 ` [RFC PATCH v1.9 13/14] livepatch: add /proc/<pid>/patch_status Josh Poimboeuf
2016-03-31  9:33   ` Jiri Slaby
2016-03-31  9:40     ` Jiri Slaby
2016-04-04 16:56     ` Josh Poimboeuf
2016-03-25 19:35 ` [RFC PATCH v1.9 14/14] livepatch: update task universe when exiting kernel Josh Poimboeuf
2016-04-14  8:47   ` Miroslav Benes
2016-04-14  8:50     ` Miroslav Benes
2016-04-14 13:39       ` Josh Poimboeuf
2016-04-18 15:01         ` [RFC PATCH 0/2] s390/klp: s390 support Miroslav Benes
2016-04-18 15:01           ` [RFC PATCH 1/2] s390: livepatch, reorganize TIF bits Miroslav Benes
2016-04-18 15:01           ` [RFC PATCH 2/2] s390/klp: update task universe when exiting kernel Miroslav Benes
2016-04-18 15:17           ` [RFC PATCH 0/2] s390/klp: s390 support Josh Poimboeuf
2016-04-14 13:23     ` [RFC PATCH v1.9 14/14] livepatch: update task universe when exiting kernel Josh Poimboeuf
2016-03-31 12:54 ` [RFC PATCH v1.9 00/14] livepatch: hybrid consistency model Miroslav Benes
2016-04-04 17:03   ` Josh Poimboeuf
2016-04-05 14:24     ` Miroslav Benes
2016-04-05 14:34       ` Josh Poimboeuf
2016-04-05 14:53         ` Miroslav Benes
2016-04-01 13:34 ` Miroslav Benes
2016-04-01 13:39 ` Petr Mladek
2016-04-01 15:38   ` Petr Mladek
2016-04-05 13:44   ` Josh Poimboeuf
2016-04-06  8:15     ` Petr Mladek
2016-04-28 18:53     ` Josh Poimboeuf
2016-06-09 14:20       ` Petr Mladek
2016-04-07 12:10 ` Petr Mladek
2016-04-07 15:08   ` Josh Poimboeuf
2016-04-07 15:47     ` Jiri Kosina
2016-04-07 18:03       ` Josh Poimboeuf
2016-04-07 18:33         ` Jiri Kosina

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