This change: commit 58eb0862c3471b931bf3412d6d02bac447d5a653 Author: Roland McGrath <roland@hack.frob.com> Date: Fri Jun 27 09:58:51 2014 -0700 MIPS: Consolidate NPTL/non versions of vfork regressed MIPS builds of librt.so, depending on how the BFD linker internals work out, which generally depends on multilib options, either an empty entry is left in the dynamic symbol table or a build failure is triggered like this: .../mips-linux-gnu/bin/ld: .../nptl/libpthread.so: invalid string offset 2765592330 >= 5154 for section `.dynstr' .../nptl/libpthread.so: could not read symbols: File format not recognized collect2: error: ld returned 1 exit status This is a bug in GNU LD and also GAS, but I think we have a bug too, in the MIPS version of pt-vfork.S, that triggers this obscure corner case. Before the change it assembled to have a symbol table like this: Symbol table '.symtab' contains 20 entries: Num: Value Size Type Bind Vis Ndx Name 0: 00000000 0 NOTYPE LOCAL DEFAULT UND 1: 00000000 0 SECTION LOCAL DEFAULT 1 2: 00000000 0 SECTION LOCAL DEFAULT 3 3: 00000000 0 SECTION LOCAL DEFAULT 4 4: 00000001 0 NOTYPE LOCAL DEFAULT ABS LOCALSZ 5: 00000018 0 NOTYPE LOCAL DEFAULT ABS FRAMESZ 6: 00000014 0 NOTYPE LOCAL DEFAULT ABS GPOFF 7: 00000000 0 SECTION LOCAL DEFAULT 11 8: 00000000 0 SECTION LOCAL DEFAULT 13 9: 00000000 0 SECTION LOCAL DEFAULT 9 10: 00000000 0 SECTION LOCAL DEFAULT 14 11: 00000000 0 SECTION LOCAL DEFAULT 16 12: 00000000 0 SECTION LOCAL DEFAULT 5 13: 00000000 0 SECTION LOCAL DEFAULT 6 14: 00000000 0 SECTION LOCAL DEFAULT 7 15: 00000000 0 SECTION LOCAL DEFAULT 18 16: 00000000 112 FUNC GLOBAL DEFAULT 1 __vfork 17: 00000000 0 OBJECT GLOBAL DEFAULT UND _gp_disp 18: 00000000 0 NOTYPE GLOBAL DEFAULT UND __syscall_error 19: 00000000 112 FUNC WEAK DEFAULT 1 vfork With the change in place the symbol table is like this instead: Symbol table '.symtab' contains 21 entries: Num: Value Size Type Bind Vis Ndx Name 0: 00000000 0 NOTYPE LOCAL DEFAULT UND 1: 00000000 0 SECTION LOCAL DEFAULT 1 2: 00000000 0 SECTION LOCAL DEFAULT 3 3: 00000000 0 SECTION LOCAL DEFAULT 4 4: 00000001 0 NOTYPE LOCAL DEFAULT ABS LOCALSZ 5: 00000018 0 NOTYPE LOCAL DEFAULT ABS FRAMESZ 6: 00000014 0 NOTYPE LOCAL DEFAULT ABS GPOFF 7: 00000000 0 SECTION LOCAL DEFAULT 11 8: 00000000 0 SECTION LOCAL DEFAULT 13 9: 00000000 0 SECTION LOCAL DEFAULT 9 10: 00000000 0 SECTION LOCAL DEFAULT 14 11: 00000000 0 SECTION LOCAL DEFAULT 16 12: 00000000 0 SECTION LOCAL DEFAULT 5 13: 00000000 0 SECTION LOCAL DEFAULT 6 14: 00000000 0 SECTION LOCAL DEFAULT 7 15: 00000000 0 SECTION LOCAL DEFAULT 18 16: 00000000 140 FUNC GLOBAL DEFAULT 1 __vfork 17: 00000000 0 OBJECT GLOBAL DEFAULT UND _gp_disp 18: 00000000 0 NOTYPE GLOBAL DEFAULT UND __syscall_error 19: 00000000 140 FUNC WEAK DEFAULT 1 vfork 20: 00000000 0 NOTYPE GLOBAL DEFAULT UND vfork@GLIBC_2.0 -- notice the undefined versioned entry for `vfork@GLIBC_2.0'. This is what confuses LD and also shouldn't have been produced by GAS in the first place. There's no further reference to that symbol, i.e. no relocation anywhere across this object file, which is why LD removes it from libpthread.so's dynsym table, however it doesn't realise early enough it shouldn't be propagating the reference to the dynsym table in the first place and as a result it leaves an uninitialised slot that may or may not be empty. The ultimate reason for this symbol's creation is a: .symver __libc_vfork, vfork@GLIBC_2.0 directive however without any `__libc_vfork' definition or reference. This is what the GAS manual has to say about this case: " For ELF targets, the `.symver' directive can be used like this: .symver NAME, NAME2@NODENAME " If the symbol NAME is not defined within the file being assembled, all references to NAME will be changed to NAME2@NODENAME. If no reference to NAME is made, NAME2@NODENAME will be removed from the symbol table." so the symbol is supposed not to be emitted. It appears though that this bug has been present in GNU binutils since forever and our other targets define `__libc_vfork', possibly just as an alias to `__vfork', so I think we should simply do the same for MIPS. The symbol does not make it to the dynsym table so such a change will not affect our ABI.
This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "GNU C Library master sources". The branch, master has been updated via b5af9297d51a43f96c5be1bafab032184690dd6f (commit) from a13d0d745ca3ea5e80506db7de0498d74d44a5b7 (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=b5af9297d51a43f96c5be1bafab032184690dd6f commit b5af9297d51a43f96c5be1bafab032184690dd6f Author: Maciej W. Rozycki <macro@codesourcery.com> Date: Wed Oct 22 15:20:37 2014 +0100 MIPS: Avoid a dangling `vfork@GLIBC_2.0' reference This satisfies a symbol reference created with: .symver __libc_vfork, vfork@GLIBC_2.0 where `__libc_vfork' has not been defined or referenced. In this case the `vfork@GLIBC_2.0' reference is supposed to be discarded, however a bug present in GAS since forever causes an undefined symbol table entry to be created. This in turn triggers a problem in the linker that can manifest itself by link errors such as: ld: libpthread.so: invalid string offset 2765592330 >= 5154 for section `.dynstr' The GAS and linker bugs need to be resolved, but we can avoid them too by providing a `__libc_vfork' definition just like our other platforms. [BZ #17485] * sysdeps/unix/sysv/linux/mips/vfork.S (__libc_vfork): Define. ----------------------------------------------------------------------- Summary of changes: ChangeLog | 5 +++++ NEWS | 3 ++- sysdeps/unix/sysv/linux/mips/vfork.S | 1 + 3 files changed, 8 insertions(+), 1 deletions(-)
This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "GNU C Library master sources". The branch, release/2.20/master has been updated via c14e752fc73d34c75d4f84f37fea8e0b1734cf98 (commit) from 1b198b7fc764c013d41d1bd7b83fed0ad3dee038 (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=c14e752fc73d34c75d4f84f37fea8e0b1734cf98 commit c14e752fc73d34c75d4f84f37fea8e0b1734cf98 Author: Maciej W. Rozycki <macro@codesourcery.com> Date: Wed Oct 22 15:20:37 2014 +0100 MIPS: Avoid a dangling `vfork@GLIBC_2.0' reference This satisfies a symbol reference created with: .symver __libc_vfork, vfork@GLIBC_2.0 where `__libc_vfork' has not been defined or referenced. In this case the `vfork@GLIBC_2.0' reference is supposed to be discarded, however a bug present in GAS since forever causes an undefined symbol table entry to be created. This in turn triggers a problem in the linker that can manifest itself by link errors such as: ld: libpthread.so: invalid string offset 2765592330 >= 5154 for section `.dynstr' The GAS and linker bugs need to be resolved, but we can avoid them too by providing a `__libc_vfork' definition just like our other platforms. [BZ #17485] * sysdeps/unix/sysv/linux/mips/vfork.S (__libc_vfork): Define. (cherry picked from commit b5af9297d51a43f96c5be1bafab032184690dd6f) Conflicts: NEWS ----------------------------------------------------------------------- Summary of changes: ChangeLog | 5 +++++ NEWS | 2 +- sysdeps/unix/sysv/linux/mips/vfork.S | 1 + 3 files changed, 7 insertions(+), 1 deletions(-)
Fixed on trunk and the 2.20 release branch as per the commit messages.