| Message ID | 20220201013257.17926-1-changbin.du@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | kallsyms: ignore all local labels prefixed by '.L' | expand |
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> Does not seem too unreasonable to me. Reviewed-by: Nathan Chancellor <nathan@kernel.org> > --- > 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[] = { > "$", /* local symbols for ARM, MIPS, etc. */ > - ".LASANPC", /* s390 kasan local symbols */ > + ".L", /* local labels, .LBB,.Ltmpxxx,.L__unnamed_xx,.LASANPC, etc. */ > "__crc_", /* modversions */ > "__efistub_", /* arm64 EFI stub namespace */ > "__kvm_nvhe_", /* arm64 non-VHE KVM namespace */ > -- > 2.32.0 > >
On Mon, Jan 31, 2022 at 5:33 PM Changbin Du <changbin.du@gmail.com> wrote: Make sure to mark the version of your patches (this is v2, IIUC). `git format-patch -v2 HEAD~` Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > > The llvm compiler can generate lots of local labels ('.LBB', '.Ltmpxxx', > '.L__unnamed_xx', etc.). These symbols usually are useless for debugging. > And they might overlap with handwritten symbols. > > Before this change, a dumpstack shows a local symbol for epc: > [ 0.040341][ T0] Hardware name: riscv-virtio,qemu (DT) > [ 0.040376][ T0] epc : .LBB6_14+0x22/0x6a > [ 0.040452][ T0] ra : restore_all+0x12/0x6e > > The simple solution is that we can ignore all local labels prefixed by '.L'. > For handwritten symbols which need to be preserved should drop the '.L' > prefix. > > After this change, the C defined symbol is shown so we can locate the > problematical code immediately: > [ 0.035795][ T0] Hardware name: riscv-virtio,qemu (DT) > [ 0.036332][ T0] epc : trace_hardirqs_on+0x54/0x13c > [ 0.036567][ T0] ra : restore_all+0x12/0x6e > > Signed-off-by: Changbin Du <changbin.du@gmail.com> > --- > scripts/kallsyms.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c > index 54ad86d13784..8caabddf817c 100644 > --- a/scripts/kallsyms.c > +++ b/scripts/kallsyms.c > @@ -108,7 +108,7 @@ static bool is_ignored_symbol(const char *name, char type) > /* Symbol names that begin with the following are ignored.*/ > static const char * const ignored_prefixes[] = { > "$", /* 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 >
On Tue, Feb 01, 2022 at 11:42:59AM -0800, Nick Desaulniers wrote: > On Mon, Jan 31, 2022 at 5:33 PM Changbin Du <changbin.du@gmail.com> wrote: > > Make sure to mark the version of your patches (this is v2, IIUC). `git > format-patch -v2 HEAD~` > Sure, I fogot to add version NO. this time. Thanks for your reminding. > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > > > > > 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> > > --- > > 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[] = { > > "$", /* local symbols for ARM, MIPS, etc. */ > > - ".LASANPC", /* s390 kasan local symbols */ > > + ".L", /* local labels, .LBB,.Ltmpxxx,.L__unnamed_xx,.LASANPC, etc. */ > > "__crc_", /* modversions */ > > "__efistub_", /* arm64 EFI stub namespace */ > > "__kvm_nvhe_", /* arm64 non-VHE KVM namespace */ > > -- > > 2.32.0 > > > > > -- > Thanks, > ~Nick Desaulniers
Hi, Masahiro, Could you consider picking up this change if you have no objection? On Tue, Feb 01, 2022 at 09:32:57AM +0800, Changbin Du wrote: > The llvm compiler can generate lots of local labels ('.LBB', '.Ltmpxxx', > '.L__unnamed_xx', etc.). These symbols usually are useless for debugging. > And they might overlap with handwritten symbols. > > Before this change, a dumpstack shows a local symbol for epc: > [ 0.040341][ T0] Hardware name: riscv-virtio,qemu (DT) > [ 0.040376][ T0] epc : .LBB6_14+0x22/0x6a > [ 0.040452][ T0] ra : restore_all+0x12/0x6e > > The simple solution is that we can ignore all local labels prefixed by '.L'. > For handwritten symbols which need to be preserved should drop the '.L' > prefix. > > After this change, the C defined symbol is shown so we can locate the > problematical code immediately: > [ 0.035795][ T0] Hardware name: riscv-virtio,qemu (DT) > [ 0.036332][ T0] epc : trace_hardirqs_on+0x54/0x13c > [ 0.036567][ T0] ra : restore_all+0x12/0x6e > > Signed-off-by: Changbin Du <changbin.du@gmail.com> > --- > scripts/kallsyms.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c > index 54ad86d13784..8caabddf817c 100644 > --- a/scripts/kallsyms.c > +++ b/scripts/kallsyms.c > @@ -108,7 +108,7 @@ static bool is_ignored_symbol(const char *name, char type) > /* Symbol names that begin with the following are ignored.*/ > static const char * const ignored_prefixes[] = { > "$", /* 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 >
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[] = { > > "$", /* local symbols for ARM, MIPS, etc. */ > > - ".LASANPC", /* s390 kasan local symbols */ > > + ".L", /* local labels, .LBB,.Ltmpxxx,.L__unnamed_xx,.LASANPC, etc. */ > > "__crc_", /* modversions */ > > "__efistub_", /* arm64 EFI stub namespace */ > > "__kvm_nvhe_", /* arm64 non-VHE KVM namespace */ > > -- > > 2.32.0 > > > > -- > Cheers, > Changbin Du
diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 54ad86d13784..8caabddf817c 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -108,7 +108,7 @@ static bool is_ignored_symbol(const char *name, char type) /* Symbol names that begin with the following are ignored.*/ static const char * const ignored_prefixes[] = { "$", /* 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 */
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> --- scripts/kallsyms.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)