Messages in this thread Patch in this message | | | Date | Tue, 21 Jul 2015 08:53:34 +0900 | From | AKASHI Takahiro <> | Subject | Re: [RFC 2/3] arm64: refactor save_stack_trace() |
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Hi
So i don't have to repost my patch here. Please use the original commit log message[1/3] as is. But please keep in mind that there is still an issue that I mentioned in the cover letter; 'Size' field is inaccurate. <reported size> = <its own dynamic local variables> + <child's local variables> and <real size> = <reported size> + <its local variables> - <child's local variables> where "dynamic" means, for example, a variable allocated like the below: int foo(int num) { int array[num]; ... } (See more details in my ascii art.)
Such usage is seldom seen in the kernel, and <reported size> is likely equal to <child's local variables>. In other words, we will see one-line *displacement* in most cases.
(We'd better mention it explicitly in the commmit?)
Thanks, -Takahiro AKASHI
On 07/21/2015 01:20 AM, Will Deacon wrote: > Hi all, > > On Fri, Jul 17, 2015 at 04:34:21PM +0100, Jungseok Lee wrote: >> On Jul 17, 2015, at 11:59 PM, Jungseok Lee wrote: >>> On Jul 17, 2015, at 11:41 PM, Steven Rostedt wrote: >>>> Thanks! Can you repost patch 1 with the changes I recommended, so that >>>> I can get an Acked-by from the arm64 maintainers and pull all the >>>> changes in together. This is fine for a 4.3 release, right? That is, it >>>> doesn't need to go into 4.2-rcs. >>>> >>> >>> It's not hard to repost a patch, but I feel like we have to wait for Akashi's response. >>> Also, it might be needed to consider Mark's comment on arch part. >>> >>> If they are okay, I will proceed. >> >> The [RFC 1/3] patch used in my environment is shaped as follows. >> I leave the hunk for *only* clear synchronization. This is why I choose this format >> instead of reposting a patch. I hope it would help to track down this thread. >> >> I think this is my best at this point. >> >> ----8<---- >> diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h >> index c5534fa..2b43e20 100644 >> --- a/arch/arm64/include/asm/ftrace.h >> +++ b/arch/arm64/include/asm/ftrace.h >> @@ -13,8 +13,9 @@ >> >> #include <asm/insn.h> >> >> -#define MCOUNT_ADDR ((unsigned long)_mcount) >> -#define MCOUNT_INSN_SIZE AARCH64_INSN_SIZE >> +#define MCOUNT_ADDR ((unsigned long)_mcount) >> +#define MCOUNT_INSN_SIZE AARCH64_INSN_SIZE >> +#define FTRACE_STACK_FRAME_OFFSET AARCH64_INSN_SIZE >> >> #ifndef __ASSEMBLY__ >> #include <linux/compat.h> >> diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c >> index 407991b..9ab67af 100644 >> --- a/arch/arm64/kernel/stacktrace.c >> +++ b/arch/arm64/kernel/stacktrace.c >> @@ -20,6 +20,7 @@ >> #include <linux/sched.h> >> #include <linux/stacktrace.h> >> >> +#include <asm/insn.h> >> #include <asm/stacktrace.h> >> >> /* >> @@ -52,7 +53,7 @@ int notrace unwind_frame(struct stackframe *frame) >> * -4 here because we care about the PC at time of bl, >> * not where the return will go. >> */ >> - frame->pc = *(unsigned long *)(fp + 8) - 4; >> + frame->pc = *(unsigned long *)(fp + 8) - AARCH64_INSN_SIZE; >> >> return 0; >> } > > The arm64 bits look fine to me: > > Acked-by: Will Deacon <will.deacon@arm.com> > > Steve: feel free to take this along with the other ftrace changes. I don't > anticipate any conflicts, but if anything crops up in -next we can sort > it out then. > > Thanks! > > Will >
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