From: duwe@lst.de (Torsten Duwe)
To: Will Deacon <will.deacon@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Julien Thierry <julien.thierry@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Ingo Molnar <mingo@redhat.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Arnd Bergmann <arnd@arndb.de>,
AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, live-patching@vger.kernel.org
Subject: [PATCH v3 4/4] arm64: reliable stacktraces
Date: Mon, 1 Oct 2018 16:16:58 +0200 (CEST) [thread overview]
Message-ID: <20181001141658.A856D68BC7@newverein.lst.de> (raw)
In-Reply-To: <20181001140910.086E768BC7@newverein.lst.de>
Make unwind_frame() report whether it had to stop normally or due to
an error condition; walk_stackframe() will pass that info.
__save_stack_trace() is used to check the validity of a frame;
save_stack_trace_tsk_reliable() can now trivially be implemented.
Modify arch/arm64/kernel/time.c for the new semantics.
Signed-off-by: Torsten Duwe <duwe@suse.de>
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -127,8 +127,9 @@ config ARM64
select HAVE_PERF_EVENTS
select HAVE_PERF_REGS
select HAVE_PERF_USER_STACK_DUMP
- select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_RCU_TABLE_FREE
+ select HAVE_REGS_AND_STACK_ACCESS_API
+ select HAVE_RELIABLE_STACKTRACE
select HAVE_STACKPROTECTOR
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_KPROBES
--- a/arch/arm64/include/asm/stacktrace.h
+++ b/arch/arm64/include/asm/stacktrace.h
@@ -33,7 +33,7 @@ struct stackframe {
};
extern int unwind_frame(struct task_struct *tsk, struct stackframe *frame);
-extern void walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
+extern int walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
int (*fn)(struct stackframe *, void *), void *data);
extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk);
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -40,6 +40,13 @@
* ldp x29, x30, [sp]
* add sp, sp, #0x10
*/
+
+/*
+ * unwind_frame -- unwind a single stack frame.
+ * Returns 0 when there are more frames to go.
+ * 1 means reached end of stack; negative (error)
+ * means stopped because information is not reliable.
+ */
int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
{
unsigned long fp = frame->fp;
@@ -81,23 +88,27 @@ int notrace unwind_frame(struct task_str
* both are NULL.
*/
if (!frame->fp && !frame->pc)
- return -EINVAL;
+ return 1;
return 0;
}
-void notrace walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
+int notrace walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
int (*fn)(struct stackframe *, void *), void *data)
{
while (1) {
int ret;
- if (fn(frame, data))
- break;
+ ret = fn(frame, data);
+ if (ret)
+ return ret;
ret = unwind_frame(tsk, frame);
if (ret < 0)
+ return ret;
+ if (ret > 0)
break;
}
+ return 0;
}
#ifdef CONFIG_STACKTRACE
@@ -145,14 +156,15 @@ void save_stack_trace_regs(struct pt_reg
trace->entries[trace->nr_entries++] = ULONG_MAX;
}
-static noinline void __save_stack_trace(struct task_struct *tsk,
+static noinline int __save_stack_trace(struct task_struct *tsk,
struct stack_trace *trace, unsigned int nosched)
{
struct stack_trace_data data;
struct stackframe frame;
+ int ret;
if (!try_get_task_stack(tsk))
- return;
+ return -EBUSY;
data.trace = trace;
data.skip = trace->skip;
@@ -171,11 +183,12 @@ static noinline void __save_stack_trace(
frame.graph = tsk->curr_ret_stack;
#endif
- walk_stackframe(tsk, &frame, save_trace, &data);
+ ret = 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);
+ return ret;
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
@@ -190,4 +203,12 @@ void save_stack_trace(struct stack_trace
}
EXPORT_SYMBOL_GPL(save_stack_trace);
+
+int save_stack_trace_tsk_reliable(struct task_struct *tsk,
+ struct stack_trace *trace)
+{
+ return __save_stack_trace(tsk, trace, 1);
+}
+EXPORT_SYMBOL_GPL(save_stack_trace_tsk_reliable);
+
#endif
--- a/arch/arm64/kernel/time.c
+++ b/arch/arm64/kernel/time.c
@@ -56,7 +56,7 @@ unsigned long profile_pc(struct pt_regs
#endif
do {
int ret = unwind_frame(NULL, &frame);
- if (ret < 0)
+ if (ret)
return 0;
} while (in_lock_functions(frame.pc));
prev parent reply other threads:[~2018-10-01 14:17 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-01 14:09 [PATCH v3 0/4] arm64 live patching Torsten Duwe
2018-10-01 14:16 ` [PATCH v3 1/4] DYNAMIC_FTRACE configurable with and without REGS Torsten Duwe
2018-10-01 14:52 ` Ard Biesheuvel
2018-10-01 15:03 ` Torsten Duwe
2018-10-01 15:06 ` Ard Biesheuvel
2018-10-01 15:10 ` Torsten Duwe
2018-10-01 15:14 ` Steven Rostedt
2018-10-01 14:16 ` [PATCH v3 2/4] arm64: implement ftrace with regs Torsten Duwe
2018-10-01 15:57 ` Ard Biesheuvel
2018-10-02 10:02 ` Torsten Duwe
2018-10-02 10:39 ` Ard Biesheuvel
2018-10-02 11:27 ` Mark Rutland
2018-10-02 12:18 ` Torsten Duwe
2018-10-02 12:57 ` Mark Rutland
2018-10-01 14:16 ` [PATCH v3 3/4] arm64: implement live patching Torsten Duwe
2018-10-17 13:39 ` Miroslav Benes
2018-10-18 12:58 ` Jessica Yu
2018-10-19 11:59 ` Miroslav Benes
2018-10-19 12:18 ` Jessica Yu
2018-10-19 15:14 ` Miroslav Benes
2018-10-19 13:46 ` Torsten Duwe
2018-10-19 13:52 ` Ard Biesheuvel
2018-10-19 15:21 ` Miroslav Benes
2018-10-20 14:10 ` Ard Biesheuvel
2018-10-22 12:53 ` Miroslav Benes
2018-10-22 14:54 ` Torsten Duwe
2018-10-23 17:55 ` [PATCH] arm64/module: use mod->klp_info section header information Jessica Yu
2018-10-23 19:32 ` kbuild test robot
2018-10-24 11:57 ` Miroslav Benes
2018-10-25 8:08 ` Petr Mladek
2018-10-25 9:00 ` Miroslav Benes
2018-10-25 11:42 ` Jessica Yu
2018-10-26 17:25 ` [PATCH v2] arm64/module: use mod->klp_info section header information for livepatch modules Jessica Yu
2018-10-29 13:24 ` Miroslav Benes
2018-10-29 13:32 ` Jessica Yu
2018-10-29 15:28 ` Will Deacon
2018-10-30 13:19 ` Jessica Yu
2018-11-01 15:18 ` Miroslav Benes
2018-11-01 16:07 ` Will Deacon
2018-11-05 12:30 ` Ard Biesheuvel
2018-11-05 17:57 ` [PATCH] arm64/module: use plt section indices for relocations Jessica Yu
2018-11-05 18:04 ` Ard Biesheuvel
2018-11-05 18:53 ` [PATCH v2] " Jessica Yu
2018-11-05 18:56 ` Ard Biesheuvel
2018-11-05 19:26 ` Will Deacon
2018-11-05 19:49 ` Jessica Yu
2018-11-06 9:44 ` Miroslav Benes
2018-10-01 14:16 ` Torsten Duwe [this message]
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