| Message ID | 20230907193828.126271-1-ajax@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | libio: Fix oversized __io_vtables | expand |
* Adam Jackson: > IO_VTABLES_LEN is the expected size of the struct in bytes, not the > number of __IO_jump_t's in the array. Drops just under 384kb from > .rodata on LP64 machines. Ouch, thanks for spotting this. I think it's this Debian and Ubuntu bug: djbdns: Fix for tests with new glibc 2.38 <https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1050371> tinydns: allocation failures with glibc 2.38/s390x <https://bugs.launchpad.net/ubuntu/+source/djbdns/+bug/2031909> > Fixes: 3020f72618e ("libio: Remove the usage of __libc_IO_vtables") > Signed-off-by: Adam Jackson <ajax@redhat.com> > --- > libio/vtables.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/libio/vtables.c b/libio/vtables.c > index 1d8ad612e94..7cb894d751d 100644 > --- a/libio/vtables.c > +++ b/libio/vtables.c > @@ -86,11 +86,11 @@ > > # pragma weak __wprintf_buffer_as_file_overflow > # pragma weak __wprintf_buffer_as_file_xsputn > #endif > > -const struct _IO_jump_t __io_vtables[IO_VTABLES_LEN] attribute_relro = > +const struct _IO_jump_t __io_vtables[IO_VTABLES_NUM] attribute_relro = > { > /* _IO_str_jumps */ > [IO_STR_JUMPS] = > { > JUMP_INIT_DUMMY, Maybe use [] and _Static_assert (array_length (__io_vtables) == IO_VTABLES_NUM, "initializer count); after the definition? Let me know if you want to make this change. I've got a machine checkout that can build glibc on all supported architectures fairly quickly. Thanks, Florian
On Fri, Sep 8, 2023 at 7:20 AM Florian Weimer <fweimer@redhat.com> wrote: Maybe use [] and > > _Static_assert (array_length (__io_vtables) == IO_VTABLES_NUM, > "initializer count); > > after the definition? > > Let me know if you want to make this change. I've got a machine > checkout that can build glibc on all supported architectures fairly > quickly. > Sure. I'll send a new patch, I spotted a grammar-o in the commit message. - ajax
diff --git a/libio/vtables.c b/libio/vtables.c index 1d8ad612e94..7cb894d751d 100644 --- a/libio/vtables.c +++ b/libio/vtables.c @@ -86,11 +86,11 @@ # pragma weak __wprintf_buffer_as_file_overflow # pragma weak __wprintf_buffer_as_file_xsputn #endif -const struct _IO_jump_t __io_vtables[IO_VTABLES_LEN] attribute_relro = +const struct _IO_jump_t __io_vtables[IO_VTABLES_NUM] attribute_relro = { /* _IO_str_jumps */ [IO_STR_JUMPS] = { JUMP_INIT_DUMMY,
IO_VTABLES_LEN is the expected size of the struct in bytes, not the number of __IO_jump_t's in the array. Drops just under 384kb from .rodata on LP64 machines. Fixes: 3020f72618e ("libio: Remove the usage of __libc_IO_vtables") Signed-off-by: Adam Jackson <ajax@redhat.com> --- libio/vtables.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)