Messages in this thread | | | From | Masahiro Yamada <> | Date | Tue, 22 Feb 2022 00:47:36 +0900 | Subject | Re: [PATCH] kallsyms: ignore all local labels prefixed by '.L' |
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On Mon, Feb 21, 2022 at 11:38 PM Changbin Du <changbin.du@gmail.com> wrote: > > Hi, Masahiro, > Could you consider picking up this change if you have no objection? > > On Tue, Feb 01, 2022 at 09:32:57AM +0800, Changbin Du wrote: > > The llvm compiler can generate lots of local labels ('.LBB', '.Ltmpxxx', > > '.L__unnamed_xx', etc.). These symbols usually are useless for debugging. > > And they might overlap with handwritten symbols. > > > > Before this change, a dumpstack shows a local symbol for epc: > > [ 0.040341][ T0] Hardware name: riscv-virtio,qemu (DT) > > [ 0.040376][ T0] epc : .LBB6_14+0x22/0x6a > > [ 0.040452][ T0] ra : restore_all+0x12/0x6e > > > > The simple solution is that we can ignore all local labels prefixed by '.L'. > > For handwritten symbols which need to be preserved should drop the '.L' > > prefix. > > > > After this change, the C defined symbol is shown so we can locate the > > problematical code immediately: > > [ 0.035795][ T0] Hardware name: riscv-virtio,qemu (DT) > > [ 0.036332][ T0] epc : trace_hardirqs_on+0x54/0x13c > > [ 0.036567][ T0] ra : restore_all+0x12/0x6e > > > > Signed-off-by: Changbin Du <changbin.du@gmail.com>
Now applied to linux-kbuild. Thanks.
> > --- > > scripts/kallsyms.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c > > index 54ad86d13784..8caabddf817c 100644 > > --- a/scripts/kallsyms.c > > +++ b/scripts/kallsyms.c > > @@ -108,7 +108,7 @@ static bool is_ignored_symbol(const char *name, char type) > > /* Symbol names that begin with the following are ignored.*/ > > static const char * const ignored_prefixes[] = { > > "$", /* local symbols for ARM, MIPS, etc. */ > > - ".LASANPC", /* s390 kasan local symbols */ > > + ".L", /* local labels, .LBB,.Ltmpxxx,.L__unnamed_xx,.LASANPC, etc. */ > > "__crc_", /* modversions */ > > "__efistub_", /* arm64 EFI stub namespace */ > > "__kvm_nvhe_", /* arm64 non-VHE KVM namespace */ > > -- > > 2.32.0 > > > > -- > Cheers, > Changbin Du
-- Best Regards Masahiro Yamada
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