From: AKASHI Takahiro <takahiro.akashi@linaro.org> To: catalin.marinas@arm.com, will.deacon@arm.com, rostedt@goodmis.org Cc: jungseoklee85@gmail.com, olof@lixom.net, broonie@kernel.org, david.griego@linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, AKASHI Takahiro <takahiro.akashi@linaro.org> Subject: [RFC 2/3] arm64: refactor save_stack_trace() Date: Mon, 13 Jul 2015 14:29:34 +0900 [thread overview] Message-ID: <1436765375-7119-3-git-send-email-takahiro.akashi@linaro.org> (raw) In-Reply-To: <1436765375-7119-1-git-send-email-takahiro.akashi@linaro.org> Ftrace's stack tracer on arm64 returns wrong information about call stacks: Depth Size Location (50 entries) ----- ---- -------- 0) 5256 0 notifier_call_chain+0x30/0x94 1) 5256 0 ftrace_call+0x0/0x4 2) 5256 0 notifier_call_chain+0x2c/0x94 3) 5256 0 raw_notifier_call_chain+0x34/0x44 4) 5256 0 timekeeping_update.constprop.9+0xb8/0x114 5) 5256 0 update_wall_time+0x408/0x6dc One of tracer functions, ftrace_call (or mcount), is unexpectedly listed. The *bare* stack dump returned by save_stack_trace() is: save_stack_trace_tsk() save_stack_trace() stack_trace_call() ftrace_ops_no_ops() ftrace_call() notifier_call_chain() raw_notifier_call_chain() ... On arm64, save_stack_trace() calls save_stack_trace_tsk() and this will result in putting additional stack frame in the returned list. This behavior, however, conflicts with stack stracer's assumption that the number of functions to be skiped as part of tracer is 4, from save_stack_trace() to mcount(), if ftrace_ops_list_func() is used. The value is hard coded in check_patch(). This patch refactors save_stack_trace() and save_stack_trace_tsk() in order to reduce the stack depth by making the common code inlined. Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> --- arch/arm64/kernel/stacktrace.c | 31 +++++++++++++++++++++++-------- 1 file changed, 23 insertions(+), 8 deletions(-) diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index 407991b..978c923 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -97,34 +97,49 @@ static int save_trace(struct stackframe *frame, void *d) return trace->nr_entries >= trace->max_entries; } -void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) +static inline void __save_stack_trace(struct stackframe *frame, + struct stack_trace *trace, int no_sched) { struct stack_trace_data data; - struct stackframe frame; data.trace = trace; data.skip = trace->skip; + data.no_sched_functions = no_sched; + + walk_stackframe(frame, save_trace, &data); + if (trace->nr_entries < trace->max_entries) + trace->entries[trace->nr_entries++] = ULONG_MAX; +} + +void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) +{ + struct stackframe frame; + int no_sched; if (tsk != current) { - data.no_sched_functions = 1; + no_sched = 1; frame.fp = thread_saved_fp(tsk); frame.sp = thread_saved_sp(tsk); frame.pc = thread_saved_pc(tsk); } else { - data.no_sched_functions = 0; + no_sched = 0; frame.fp = (unsigned long)__builtin_frame_address(0); frame.sp = current_stack_pointer; frame.pc = (unsigned long)save_stack_trace_tsk; } - walk_stackframe(&frame, save_trace, &data); - if (trace->nr_entries < trace->max_entries) - trace->entries[trace->nr_entries++] = ULONG_MAX; + __save_stack_trace(&frame, trace, no_sched); } void save_stack_trace(struct stack_trace *trace) { - save_stack_trace_tsk(current, trace); + struct stackframe frame; + + frame.fp = (unsigned long)__builtin_frame_address(0); + frame.sp = current_stack_pointer; + frame.pc = (unsigned long)save_stack_trace_tsk; + + __save_stack_trace(&frame, trace, 0); } EXPORT_SYMBOL_GPL(save_stack_trace); #endif -- 1.7.9.5
WARNING: multiple messages have this Message-ID (diff)
From: takahiro.akashi@linaro.org (AKASHI Takahiro) To: linux-arm-kernel@lists.infradead.org Subject: [RFC 2/3] arm64: refactor save_stack_trace() Date: Mon, 13 Jul 2015 14:29:34 +0900 [thread overview] Message-ID: <1436765375-7119-3-git-send-email-takahiro.akashi@linaro.org> (raw) In-Reply-To: <1436765375-7119-1-git-send-email-takahiro.akashi@linaro.org> Ftrace's stack tracer on arm64 returns wrong information about call stacks: Depth Size Location (50 entries) ----- ---- -------- 0) 5256 0 notifier_call_chain+0x30/0x94 1) 5256 0 ftrace_call+0x0/0x4 2) 5256 0 notifier_call_chain+0x2c/0x94 3) 5256 0 raw_notifier_call_chain+0x34/0x44 4) 5256 0 timekeeping_update.constprop.9+0xb8/0x114 5) 5256 0 update_wall_time+0x408/0x6dc One of tracer functions, ftrace_call (or mcount), is unexpectedly listed. The *bare* stack dump returned by save_stack_trace() is: save_stack_trace_tsk() save_stack_trace() stack_trace_call() ftrace_ops_no_ops() ftrace_call() notifier_call_chain() raw_notifier_call_chain() ... On arm64, save_stack_trace() calls save_stack_trace_tsk() and this will result in putting additional stack frame in the returned list. This behavior, however, conflicts with stack stracer's assumption that the number of functions to be skiped as part of tracer is 4, from save_stack_trace() to mcount(), if ftrace_ops_list_func() is used. The value is hard coded in check_patch(). This patch refactors save_stack_trace() and save_stack_trace_tsk() in order to reduce the stack depth by making the common code inlined. Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> --- arch/arm64/kernel/stacktrace.c | 31 +++++++++++++++++++++++-------- 1 file changed, 23 insertions(+), 8 deletions(-) diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index 407991b..978c923 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -97,34 +97,49 @@ static int save_trace(struct stackframe *frame, void *d) return trace->nr_entries >= trace->max_entries; } -void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) +static inline void __save_stack_trace(struct stackframe *frame, + struct stack_trace *trace, int no_sched) { struct stack_trace_data data; - struct stackframe frame; data.trace = trace; data.skip = trace->skip; + data.no_sched_functions = no_sched; + + walk_stackframe(frame, save_trace, &data); + if (trace->nr_entries < trace->max_entries) + trace->entries[trace->nr_entries++] = ULONG_MAX; +} + +void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) +{ + struct stackframe frame; + int no_sched; if (tsk != current) { - data.no_sched_functions = 1; + no_sched = 1; frame.fp = thread_saved_fp(tsk); frame.sp = thread_saved_sp(tsk); frame.pc = thread_saved_pc(tsk); } else { - data.no_sched_functions = 0; + no_sched = 0; frame.fp = (unsigned long)__builtin_frame_address(0); frame.sp = current_stack_pointer; frame.pc = (unsigned long)save_stack_trace_tsk; } - walk_stackframe(&frame, save_trace, &data); - if (trace->nr_entries < trace->max_entries) - trace->entries[trace->nr_entries++] = ULONG_MAX; + __save_stack_trace(&frame, trace, no_sched); } void save_stack_trace(struct stack_trace *trace) { - save_stack_trace_tsk(current, trace); + struct stackframe frame; + + frame.fp = (unsigned long)__builtin_frame_address(0); + frame.sp = current_stack_pointer; + frame.pc = (unsigned long)save_stack_trace_tsk; + + __save_stack_trace(&frame, trace, 0); } EXPORT_SYMBOL_GPL(save_stack_trace); #endif -- 1.7.9.5
next prev parent reply other threads:[~2015-07-13 5:30 UTC|newest] Thread overview: 106+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-07-13 5:29 [RFC 0/3] arm64: ftrace: fix incorrect output from stack tracer AKASHI Takahiro 2015-07-13 5:29 ` AKASHI Takahiro 2015-07-13 5:29 ` [RFC 1/3] ftrace: adjust a function's pc to search for in check_stack() for arm64 AKASHI Takahiro 2015-07-13 5:29 ` AKASHI Takahiro 2015-07-13 15:24 ` Steven Rostedt 2015-07-13 15:24 ` Steven Rostedt 2015-07-15 0:22 ` AKASHI Takahiro 2015-07-15 0:22 ` AKASHI Takahiro 2015-07-13 5:29 ` AKASHI Takahiro [this message] 2015-07-13 5:29 ` [RFC 2/3] arm64: refactor save_stack_trace() AKASHI Takahiro 2015-07-14 12:47 ` Jungseok Lee 2015-07-14 12:47 ` Jungseok Lee 2015-07-14 13:31 ` Steven Rostedt 2015-07-14 13:31 ` Steven Rostedt 2015-07-15 0:20 ` AKASHI Takahiro 2015-07-15 0:20 ` AKASHI Takahiro 2015-07-15 2:51 ` Steven Rostedt 2015-07-15 2:51 ` Steven Rostedt 2015-07-15 11:41 ` AKASHI Takahiro 2015-07-15 11:41 ` AKASHI Takahiro 2015-07-15 14:55 ` Steven Rostedt 2015-07-15 14:55 ` Steven Rostedt 2015-07-15 16:13 ` Steven Rostedt 2015-07-15 16:13 ` Steven Rostedt 2015-07-16 0:27 ` AKASHI Takahiro 2015-07-16 0:27 ` AKASHI Takahiro 2015-07-16 1:08 ` AKASHI Takahiro 2015-07-16 1:08 ` AKASHI Takahiro 2015-07-16 1:38 ` Steven Rostedt 2015-07-16 1:38 ` Steven Rostedt 2015-07-17 10:46 ` Will Deacon 2015-07-17 10:46 ` Will Deacon 2015-07-16 13:29 ` Jungseok Lee 2015-07-16 13:29 ` Jungseok Lee 2015-07-16 13:54 ` Jungseok Lee 2015-07-16 13:54 ` Jungseok Lee 2015-07-16 14:24 ` Steven Rostedt 2015-07-16 14:24 ` Steven Rostedt 2015-07-16 15:01 ` Jungseok Lee 2015-07-16 15:01 ` Jungseok Lee 2015-07-16 15:31 ` Steven Rostedt 2015-07-16 15:31 ` Steven Rostedt 2015-07-16 15:52 ` Jungseok Lee 2015-07-16 15:52 ` Jungseok Lee 2015-07-16 20:22 ` Steven Rostedt 2015-07-16 20:22 ` Steven Rostedt 2015-07-17 2:49 ` AKASHI Takahiro 2015-07-17 2:49 ` AKASHI Takahiro 2015-07-17 3:21 ` Steven Rostedt 2015-07-17 3:21 ` Steven Rostedt 2015-07-16 16:16 ` Steven Rostedt 2015-07-16 16:16 ` Steven Rostedt 2015-07-17 12:40 ` Mark Rutland 2015-07-17 12:40 ` Mark Rutland 2015-07-17 12:51 ` Steven Rostedt 2015-07-17 12:51 ` Steven Rostedt 2015-07-17 13:00 ` Steven Rostedt 2015-07-17 13:00 ` Steven Rostedt 2015-07-17 14:28 ` Jungseok Lee 2015-07-17 14:28 ` Jungseok Lee 2015-07-17 14:41 ` Steven Rostedt 2015-07-17 14:41 ` Steven Rostedt 2015-07-17 14:59 ` Jungseok Lee 2015-07-17 14:59 ` Jungseok Lee 2015-07-17 15:34 ` Jungseok Lee 2015-07-17 15:34 ` Jungseok Lee 2015-07-17 16:01 ` Steven Rostedt 2015-07-17 16:01 ` Steven Rostedt 2015-07-20 16:20 ` Will Deacon 2015-07-20 16:20 ` Will Deacon 2015-07-20 23:53 ` AKASHI Takahiro 2015-07-20 23:53 ` AKASHI Takahiro 2015-07-21 10:26 ` AKASHI Takahiro 2015-07-21 10:26 ` AKASHI Takahiro 2015-07-21 14:34 ` Jungseok Lee 2015-07-21 14:34 ` Jungseok Lee 2015-08-03 9:09 ` Will Deacon 2015-08-03 9:09 ` Will Deacon 2015-08-03 14:01 ` Steven Rostedt 2015-08-03 14:01 ` Steven Rostedt 2015-08-03 14:04 ` Will Deacon 2015-08-03 14:04 ` Will Deacon 2015-08-03 16:30 ` Jungseok Lee 2015-08-03 16:30 ` Jungseok Lee 2015-08-03 16:57 ` Steven Rostedt 2015-08-03 16:57 ` Steven Rostedt 2015-08-03 17:22 ` Jungseok Lee 2015-08-03 17:22 ` Jungseok Lee 2015-08-03 17:32 ` Steven Rostedt 2015-08-03 17:32 ` Steven Rostedt 2015-08-04 7:41 ` AKASHI Takahiro 2015-08-04 7:41 ` AKASHI Takahiro 2015-07-17 2:04 ` AKASHI Takahiro 2015-07-17 2:04 ` AKASHI Takahiro 2015-07-17 14:38 ` Jungseok Lee 2015-07-17 14:38 ` Jungseok Lee 2015-07-16 14:28 ` Mark Rutland 2015-07-16 14:28 ` Mark Rutland 2015-07-16 14:34 ` Steven Rostedt 2015-07-16 14:34 ` Steven Rostedt 2015-07-17 2:09 ` AKASHI Takahiro 2015-07-17 2:09 ` AKASHI Takahiro 2015-07-13 5:29 ` [RFC 3/3] arm64: ftrace: mcount() should not create a stack frame AKASHI Takahiro 2015-07-13 5:29 ` AKASHI Takahiro 2015-07-13 15:01 ` [RFC 0/3] arm64: ftrace: fix incorrect output from stack tracer Jungseok Lee 2015-07-13 15:01 ` Jungseok Lee
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