Commit a96843372331 ("kbuild: explicitly specify the build id style")
explicitly set the build ID style to SHA1. Commit c2c81bb2f691 ("RISC-V:
Fix the VDSO symbol generaton for binutils-2.35+") undid this change,
likely unintentionally.
Restore it so that the build ID style stays consistent across the tree
regardless of linker.
Fixes: c2c81bb2f691 ("RISC-V: Fix the VDSO symbol generaton for binutils-2.35+")
Signed-off-by: Nathan Chancellor <[email protected]>
---
arch/riscv/kernel/vdso/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
index cb8f9e4cfcbf..0cfd6da784f8 100644
--- a/arch/riscv/kernel/vdso/Makefile
+++ b/arch/riscv/kernel/vdso/Makefile
@@ -44,7 +44,7 @@ SYSCFLAGS_vdso.so.dbg = $(c_flags)
$(obj)/vdso.so.dbg: $(src)/vdso.lds $(obj-vdso) FORCE
$(call if_changed,vdsold)
SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \
- -Wl,--build-id -Wl,--hash-style=both
+ -Wl,--build-id=sha1 -Wl,--hash-style=both
# We also create a special relocatable object that should mirror the symbol
# table and layout of the linked DSO. With ld --just-symbols we can then
base-commit: c2c81bb2f69138f902e1a58d3bef6ad97fb8a92c
--
2.29.2
On Sun, Nov 8, 2020 at 12:37 PM Nathan Chancellor
<[email protected]> wrote:
>
> Commit a96843372331 ("kbuild: explicitly specify the build id style")
> explicitly set the build ID style to SHA1. Commit c2c81bb2f691 ("RISC-V:
> Fix the VDSO symbol generaton for binutils-2.35+") undid this change,
> likely unintentionally.
>
> Restore it so that the build ID style stays consistent across the tree
> regardless of linker.
>
> Fixes: c2c81bb2f691 ("RISC-V: Fix the VDSO symbol generaton for binutils-2.35+")
> Signed-off-by: Nathan Chancellor <[email protected]>
Thanks for the fixup!
Reviewed-by: Nick Desaulniers <[email protected]>
(I'm curious what --build-id linker flag does, and what kind of spooky
bugs that led to a96843372331?)
> ---
> arch/riscv/kernel/vdso/Makefile | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
> index cb8f9e4cfcbf..0cfd6da784f8 100644
> --- a/arch/riscv/kernel/vdso/Makefile
> +++ b/arch/riscv/kernel/vdso/Makefile
> @@ -44,7 +44,7 @@ SYSCFLAGS_vdso.so.dbg = $(c_flags)
> $(obj)/vdso.so.dbg: $(src)/vdso.lds $(obj-vdso) FORCE
> $(call if_changed,vdsold)
> SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \
> - -Wl,--build-id -Wl,--hash-style=both
> + -Wl,--build-id=sha1 -Wl,--hash-style=both
>
> # We also create a special relocatable object that should mirror the symbol
> # table and layout of the linked DSO. With ld --just-symbols we can then
>
> base-commit: c2c81bb2f69138f902e1a58d3bef6ad97fb8a92c
> --
> 2.29.2
>
> --
> You received this message because you are subscribed to the Google Groups "Clang Built Linux" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
> To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/20201108203737.94270-1-natechancellor%40gmail.com.
--
Thanks,
~Nick Desaulniers
On Thu, Nov 12, 2020 at 4:53 PM Nick Desaulniers
<[email protected]> wrote:
>
> On Sun, Nov 8, 2020 at 12:37 PM Nathan Chancellor
> <[email protected]> wrote:
> >
> > Commit a96843372331 ("kbuild: explicitly specify the build id style")
> > explicitly set the build ID style to SHA1. Commit c2c81bb2f691 ("RISC-V:
> > Fix the VDSO symbol generaton for binutils-2.35+") undid this change,
> > likely unintentionally.
> >
> > Restore it so that the build ID style stays consistent across the tree
> > regardless of linker.
> >
> > Fixes: c2c81bb2f691 ("RISC-V: Fix the VDSO symbol generaton for binutils-2.35+")
> > Signed-off-by: Nathan Chancellor <[email protected]>
>
> Thanks for the fixup!
>
> Reviewed-by: Nick Desaulniers <[email protected]>
>
> (I'm curious what --build-id linker flag does, and what kind of spooky
> bugs that led to a96843372331?)
>
--build-id generates a unique "build id" for the build. It can use
several different algorithms to do this. The BFD linker uses sha1 by
default while LLD uses a "fast" algorithm. The difference is that the
fast algorithm generates a shorter build id. This shouldn't matter in
general, but there are some tools out there that expect the build id
to be of a certain length, i.e. the BFD style's length, because BFD is
more prevalent. The obvious response "well, why don't they just change
the expected length?" is difficult in all situations. (Once an
assumption is made, it's hard to backtrack.)
You can add this if you like:
Reviewed-by: Bill Wendling <[email protected]>
> > ---
> > arch/riscv/kernel/vdso/Makefile | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
> > index cb8f9e4cfcbf..0cfd6da784f8 100644
> > --- a/arch/riscv/kernel/vdso/Makefile
> > +++ b/arch/riscv/kernel/vdso/Makefile
> > @@ -44,7 +44,7 @@ SYSCFLAGS_vdso.so.dbg = $(c_flags)
> > $(obj)/vdso.so.dbg: $(src)/vdso.lds $(obj-vdso) FORCE
> > $(call if_changed,vdsold)
> > SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \
> > - -Wl,--build-id -Wl,--hash-style=both
> > + -Wl,--build-id=sha1 -Wl,--hash-style=both
> >
> > # We also create a special relocatable object that should mirror the symbol
> > # table and layout of the linked DSO. With ld --just-symbols we can then
> >
> > base-commit: c2c81bb2f69138f902e1a58d3bef6ad97fb8a92c
> > --
> > 2.29.2
> >
> > --
> > You received this message because you are subscribed to the Google Groups "Clang Built Linux" group.
> > To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
> > To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/20201108203737.94270-1-natechancellor%40gmail.com.
>
>
>
> --
> Thanks,
> ~Nick Desaulniers
On Thu, Nov 12, 2020 at 5:03 PM Bill Wendling <[email protected]> wrote:
>
> On Thu, Nov 12, 2020 at 4:53 PM Nick Desaulniers
> <[email protected]> wrote:
> >
> > On Sun, Nov 8, 2020 at 12:37 PM Nathan Chancellor
> > <[email protected]> wrote:
> > >
> > > Commit a96843372331 ("kbuild: explicitly specify the build id style")
> > > explicitly set the build ID style to SHA1. Commit c2c81bb2f691 ("RISC-V:
> > > Fix the VDSO symbol generaton for binutils-2.35+") undid this change,
> > > likely unintentionally.
> > >
> > > Restore it so that the build ID style stays consistent across the tree
> > > regardless of linker.
> > >
> > > Fixes: c2c81bb2f691 ("RISC-V: Fix the VDSO symbol generaton for binutils-2.35+")
> > > Signed-off-by: Nathan Chancellor <[email protected]>
> >
> > Thanks for the fixup!
> >
> > Reviewed-by: Nick Desaulniers <[email protected]>
> >
> > (I'm curious what --build-id linker flag does, and what kind of spooky
> > bugs that led to a96843372331?)
> >
> --build-id generates a unique "build id" for the build. It can use
> several different algorithms to do this. The BFD linker uses sha1 by
> default while LLD uses a "fast" algorithm. The difference is that the
> fast algorithm generates a shorter build id. This shouldn't matter in
> general, but there are some tools out there that expect the build id
> to be of a certain length, i.e. the BFD style's length, because BFD is
> more prevalent. The obvious response "well, why don't they just change
> the expected length?" is difficult in all situations. (Once an
> assumption is made, it's hard to backtrack.)
>
> You can add this if you like:
>
> Reviewed-by: Bill Wendling <[email protected]>
Cool, thanks for the context, and the review!
>
> > > ---
> > > arch/riscv/kernel/vdso/Makefile | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
> > > index cb8f9e4cfcbf..0cfd6da784f8 100644
> > > --- a/arch/riscv/kernel/vdso/Makefile
> > > +++ b/arch/riscv/kernel/vdso/Makefile
> > > @@ -44,7 +44,7 @@ SYSCFLAGS_vdso.so.dbg = $(c_flags)
> > > $(obj)/vdso.so.dbg: $(src)/vdso.lds $(obj-vdso) FORCE
> > > $(call if_changed,vdsold)
> > > SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \
> > > - -Wl,--build-id -Wl,--hash-style=both
> > > + -Wl,--build-id=sha1 -Wl,--hash-style=both
> > >
> > > # We also create a special relocatable object that should mirror the symbol
> > > # table and layout of the linked DSO. With ld --just-symbols we can then
> > >
> > > base-commit: c2c81bb2f69138f902e1a58d3bef6ad97fb8a92c
> > > --
> > > 2.29.2
> > >
> > > --
> > > You received this message because you are subscribed to the Google Groups "Clang Built Linux" group.
> > > To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
> > > To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/20201108203737.94270-1-natechancellor%40gmail.com.
> >
> >
> >
> > --
> > Thanks,
> > ~Nick Desaulniers
--
Thanks,
~Nick Desaulniers
On Sun, 08 Nov 2020 12:37:37 PST (-0800), [email protected] wrote:
> Commit a96843372331 ("kbuild: explicitly specify the build id style")
> explicitly set the build ID style to SHA1. Commit c2c81bb2f691 ("RISC-V:
> Fix the VDSO symbol generaton for binutils-2.35+") undid this change,
> likely unintentionally.
>
> Restore it so that the build ID style stays consistent across the tree
> regardless of linker.
>
> Fixes: c2c81bb2f691 ("RISC-V: Fix the VDSO symbol generaton for binutils-2.35+")
> Signed-off-by: Nathan Chancellor <[email protected]>
> ---
> arch/riscv/kernel/vdso/Makefile | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
> index cb8f9e4cfcbf..0cfd6da784f8 100644
> --- a/arch/riscv/kernel/vdso/Makefile
> +++ b/arch/riscv/kernel/vdso/Makefile
> @@ -44,7 +44,7 @@ SYSCFLAGS_vdso.so.dbg = $(c_flags)
> $(obj)/vdso.so.dbg: $(src)/vdso.lds $(obj-vdso) FORCE
> $(call if_changed,vdsold)
> SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \
> - -Wl,--build-id -Wl,--hash-style=both
> + -Wl,--build-id=sha1 -Wl,--hash-style=both
>
> # We also create a special relocatable object that should mirror the symbol
> # table and layout of the linked DSO. With ld --just-symbols we can then
>
> base-commit: c2c81bb2f69138f902e1a58d3bef6ad97fb8a92c
Sorry about that. This is on fixes.