Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index 4989f7e..a336cb1 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -1,23 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* Stack tracing support
*
* Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/ftrace.h>
+#include <linux/kprobes.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/sched/task_stack.h>
@@ -40,9 +30,18 @@
* ldp x29, x30, [sp]
* add sp, sp, #0x10
*/
+
+/*
+ * Unwind from one frame record (A) to the next frame record (B).
+ *
+ * We terminate early if the location of B indicates a malformed chain of frame
+ * records (e.g. a cycle), determined based on the location and fp value of A
+ * and the location (but not the fp value) of B.
+ */
int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
{
unsigned long fp = frame->fp;
+ struct stack_info info;
if (fp & 0xf)
return -EINVAL;
@@ -50,27 +49,55 @@
if (!tsk)
tsk = current;
- if (!on_accessible_stack(tsk, fp, NULL))
+ if (!on_accessible_stack(tsk, fp, &info))
return -EINVAL;
+ if (test_bit(info.type, frame->stacks_done))
+ return -EINVAL;
+
+ /*
+ * As stacks grow downward, any valid record on the same stack must be
+ * at a strictly higher address than the prior record.
+ *
+ * Stacks can nest in several valid orders, e.g.
+ *
+ * TASK -> IRQ -> OVERFLOW -> SDEI_NORMAL
+ * TASK -> SDEI_NORMAL -> SDEI_CRITICAL -> OVERFLOW
+ *
+ * ... but the nesting itself is strict. Once we transition from one
+ * stack to another, it's never valid to unwind back to that first
+ * stack.
+ */
+ if (info.type == frame->prev_type) {
+ if (fp <= frame->prev_fp)
+ return -EINVAL;
+ } else {
+ set_bit(frame->prev_type, frame->stacks_done);
+ }
+
+ /*
+ * Record this frame record's values and location. The prev_fp and
+ * prev_type are only meaningful to the next unwind_frame() invocation.
+ */
frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp));
frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8));
+ frame->prev_fp = fp;
+ frame->prev_type = info.type;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
if (tsk->ret_stack &&
(frame->pc == (unsigned long)return_to_handler)) {
- if (WARN_ON_ONCE(frame->graph == -1))
- return -EINVAL;
- if (frame->graph < -1)
- frame->graph += FTRACE_NOTRACE_DEPTH;
-
+ struct ftrace_ret_stack *ret_stack;
/*
* This is a case where function graph tracer has
* modified a return address (LR) in a stack frame
* to hook a function return.
* So replace it to an original value.
*/
- frame->pc = tsk->ret_stack[frame->graph--].ret;
+ ret_stack = ftrace_graph_get_ret_stack(tsk, frame->graph++);
+ if (WARN_ON_ONCE(!ret_stack))
+ return -EINVAL;
+ frame->pc = ret_stack->ret;
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
@@ -85,6 +112,7 @@
return 0;
}
+NOKPROBE_SYMBOL(unwind_frame);
void notrace walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
int (*fn)(struct stackframe *, void *), void *data)
@@ -99,6 +127,7 @@
break;
}
}
+NOKPROBE_SYMBOL(walk_stackframe);
#ifdef CONFIG_STACKTRACE
struct stack_trace_data {
@@ -134,16 +163,10 @@
data.skip = trace->skip;
data.no_sched_functions = 0;
- frame.fp = regs->regs[29];
- frame.pc = regs->pc;
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- frame.graph = current->curr_ret_stack;
-#endif
-
+ start_backtrace(&frame, regs->regs[29], regs->pc);
walk_stackframe(current, &frame, save_trace, &data);
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
}
+EXPORT_SYMBOL_GPL(save_stack_trace_regs);
static noinline void __save_stack_trace(struct task_struct *tsk,
struct stack_trace *trace, unsigned int nosched)
@@ -159,21 +182,17 @@
data.no_sched_functions = nosched;
if (tsk != current) {
- frame.fp = thread_saved_fp(tsk);
- frame.pc = thread_saved_pc(tsk);
+ start_backtrace(&frame, thread_saved_fp(tsk),
+ thread_saved_pc(tsk));
} else {
/* We don't want this function nor the caller */
data.skip += 2;
- frame.fp = (unsigned long)__builtin_frame_address(0);
- frame.pc = (unsigned long)__save_stack_trace;
+ start_backtrace(&frame,
+ (unsigned long)__builtin_frame_address(0),
+ (unsigned long)__save_stack_trace);
}
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- frame.graph = tsk->curr_ret_stack;
-#endif
walk_stackframe(tsk, &frame, save_trace, &data);
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
put_task_stack(tsk);
}