From: AKASHI Takahiro <takahiro.akashi@linaro.org> To: Steven Rostedt <rostedt@goodmis.org> Cc: catalin.marinas@arm.com, will.deacon@arm.com, jungseoklee85@gmail.com, olof@lixom.net, broonie@kernel.org, david.griego@linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 1/7] arm64: ftrace: adjust callsite addresses examined by stack tracer Date: Wed, 14 Oct 2015 14:09:25 +0900 [thread overview] Message-ID: <561DE385.1040005@linaro.org> (raw) In-Reply-To: <20151013113750.0fdecd33@gandalf.local.home> On 10/14/2015 12:37 AM, Steven Rostedt wrote: > On Thu, 8 Oct 2015 19:01:38 +0900 > AKASHI Takahiro <takahiro.akashi@linaro.org> wrote: > >> extern int stack_tracer_enabled; >> int >> stack_trace_sysctl(struct ctl_table *table, int write, >> diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c >> index b746399..30521ea 100644 >> --- a/kernel/trace/trace_stack.c >> +++ b/kernel/trace/trace_stack.c >> @@ -105,7 +105,7 @@ check_stack(unsigned long ip, unsigned long *stack) >> >> /* Skip over the overhead of the stack tracer itself */ >> for (i = 0; i < max_stack_trace.nr_entries; i++) { >> - if (stack_dump_trace[i] == ip) >> + if ((stack_dump_trace[i] + FTRACE_STACK_FRAME_OFFSET) == ip) >> break; >> } >> >> @@ -133,7 +133,8 @@ check_stack(unsigned long ip, unsigned long *stack) >> for (; p < top && i < max_stack_trace.nr_entries; p++) { >> if (stack_dump_trace[i] == ULONG_MAX) >> break; >> - if (*p == stack_dump_trace[i]) { >> + if (*p == (stack_dump_trace[i] >> + + FTRACE_STACK_FRAME_OFFSET)) { > > I'm fine with the patch, but this is one of those cases that I think > the 80 column max limit produces uglier code than just going a little > over. > > Or, we can add a helper variable in both locations: > > addr = stack_dump_trace[i] + FTRACE_STACK_FRAME_OFFSET; > if (*p == addr) { > > gcc should be smart enough to optimize out the addr variable. Thanks, I will take this. (please note that this patch won't be necessary if my patch5,6 and 7 are accepted.) -Takahiro AKASHI > -- Steve > >> stack_dump_trace[x] = stack_dump_trace[i++]; >> this_size = stack_dump_index[x++] = >> (top - p) * sizeof(unsigned long); >
WARNING: multiple messages have this Message-ID (diff)
From: takahiro.akashi@linaro.org (AKASHI Takahiro) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v3 1/7] arm64: ftrace: adjust callsite addresses examined by stack tracer Date: Wed, 14 Oct 2015 14:09:25 +0900 [thread overview] Message-ID: <561DE385.1040005@linaro.org> (raw) In-Reply-To: <20151013113750.0fdecd33@gandalf.local.home> On 10/14/2015 12:37 AM, Steven Rostedt wrote: > On Thu, 8 Oct 2015 19:01:38 +0900 > AKASHI Takahiro <takahiro.akashi@linaro.org> wrote: > >> extern int stack_tracer_enabled; >> int >> stack_trace_sysctl(struct ctl_table *table, int write, >> diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c >> index b746399..30521ea 100644 >> --- a/kernel/trace/trace_stack.c >> +++ b/kernel/trace/trace_stack.c >> @@ -105,7 +105,7 @@ check_stack(unsigned long ip, unsigned long *stack) >> >> /* Skip over the overhead of the stack tracer itself */ >> for (i = 0; i < max_stack_trace.nr_entries; i++) { >> - if (stack_dump_trace[i] == ip) >> + if ((stack_dump_trace[i] + FTRACE_STACK_FRAME_OFFSET) == ip) >> break; >> } >> >> @@ -133,7 +133,8 @@ check_stack(unsigned long ip, unsigned long *stack) >> for (; p < top && i < max_stack_trace.nr_entries; p++) { >> if (stack_dump_trace[i] == ULONG_MAX) >> break; >> - if (*p == stack_dump_trace[i]) { >> + if (*p == (stack_dump_trace[i] >> + + FTRACE_STACK_FRAME_OFFSET)) { > > I'm fine with the patch, but this is one of those cases that I think > the 80 column max limit produces uglier code than just going a little > over. > > Or, we can add a helper variable in both locations: > > addr = stack_dump_trace[i] + FTRACE_STACK_FRAME_OFFSET; > if (*p == addr) { > > gcc should be smart enough to optimize out the addr variable. Thanks, I will take this. (please note that this patch won't be necessary if my patch5,6 and 7 are accepted.) -Takahiro AKASHI > -- Steve > >> stack_dump_trace[x] = stack_dump_trace[i++]; >> this_size = stack_dump_index[x++] = >> (top - p) * sizeof(unsigned long); >
next prev parent reply other threads:[~2015-10-14 5:09 UTC|newest] Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-10-08 10:01 [PATCH v3 0/7] arm64: ftrace: fix incorrect output from stack tracer AKASHI Takahiro 2015-10-08 10:01 ` AKASHI Takahiro 2015-10-08 10:01 ` [PATCH v3 1/7] arm64: ftrace: adjust callsite addresses examined by " AKASHI Takahiro 2015-10-08 10:01 ` AKASHI Takahiro 2015-10-13 15:15 ` Jungseok Lee 2015-10-13 15:15 ` Jungseok Lee 2015-10-13 15:37 ` Steven Rostedt 2015-10-13 15:37 ` Steven Rostedt 2015-10-14 5:09 ` AKASHI Takahiro [this message] 2015-10-14 5:09 ` AKASHI Takahiro 2015-10-08 10:01 ` [PATCH v3 2/7] arm64: ftrace: modify a stack frame in a safe way AKASHI Takahiro 2015-10-08 10:01 ` AKASHI Takahiro 2015-10-08 10:01 ` [PATCH v3 3/7] arm64: ftrace: fix a stack tracer's output under function graph tracer AKASHI Takahiro 2015-10-08 10:01 ` AKASHI Takahiro 2015-10-09 6:46 ` kbuild test robot 2015-10-09 6:46 ` kbuild test robot 2015-10-13 15:24 ` Jungseok Lee 2015-10-13 15:24 ` Jungseok Lee 2015-10-14 5:03 ` AKASHI Takahiro 2015-10-14 5:03 ` AKASHI Takahiro 2015-10-08 10:01 ` [PATCH v3 4/7] arm64: ftrace: allow for tracing leaf functions AKASHI Takahiro 2015-10-08 10:01 ` AKASHI Takahiro 2015-10-08 10:01 ` [PATCH v3 5/7] ftrace: allow arch-specific stack tracer AKASHI Takahiro 2015-10-08 10:01 ` AKASHI Takahiro 2015-10-13 15:45 ` Steven Rostedt 2015-10-13 15:45 ` Steven Rostedt 2015-10-08 10:01 ` [PATCH v3 6/7] arm64: insn: add instruction decoders for ldp/stp and add/sub AKASHI Takahiro 2015-10-08 10:01 ` AKASHI Takahiro 2015-10-08 10:01 ` [PATCH v3 7/7] arm64: ftrace: add arch-specific stack tracer AKASHI Takahiro 2015-10-08 10:01 ` AKASHI Takahiro 2015-10-09 6:41 ` kbuild test robot 2015-10-09 6:41 ` kbuild test robot 2015-10-08 14:45 ` [PATCH v3 0/7] arm64: ftrace: fix incorrect output from " Jungseok Lee 2015-10-08 14:45 ` Jungseok Lee 2015-10-22 14:05 ` Jungseok Lee 2015-10-22 14:05 ` Jungseok Lee 2015-10-28 15:23 ` Will Deacon 2015-10-28 15:23 ` Will Deacon 2015-10-29 5:24 ` AKASHI Takahiro 2015-10-29 5:24 ` AKASHI Takahiro
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