[Bug ld/23428] ld does not put program headers in a code-only load segment
https://sourceware.org/bugzilla/show_bug.cgi?id=23428 --- Comment #14 from nsz at port70 dot net --- > @Szabolcs: If you rebuild gcc-8 on Debian testing with "--enable-cet=auto" > added to CONFARGS in debian/rules2, then you should be able to reproduce the > musl-gcc crash (after removing the --build-id workaround from > musl-gcc.specs!). > > (It appears that "--enable-cet=auto" is the important difference between > Arch's > and Debian's GCC packages.) thanks, i could reproduce the issue: it seems ld tries to add a dummy .note.gnu.property to force the program headers into a load segment, but if there is already a .note.gnu.property in some of the input object files then it just tries to merge those and don't add a dummy note at all, however the merging rules may produce an empty note in the end and then the note section is dropped. # cat i.c int i; # gcc -fcf-protection=full -c i.c # readelf -n i.o Displaying notes found in: .note.gnu.property Owner Data size Description GNU 0x0010 NT_GNU_PROPERTY_TYPE_0 Properties: x86 feature: IBT, SHSTK # cat t.s .globl _start _start: ret # gcc -c t.s # ld t.o # readelf -ln a.out Elf file type is EXEC (Executable file) Entry point 0x401000 There are 3 program headers, starting at offset 64 Program Headers: Type Offset VirtAddr PhysAddr FileSizMemSiz Flags Align LOAD 0x 0x0040 0x0040 0x0108 0x0108 R 0x1000 LOAD 0x1000 0x00401000 0x00401000 0x0001 0x0001 R E0x1000 NOTE 0x00e8 0x004000e8 0x004000e8 0x0020 0x0020 R 0x8 Section to Segment mapping: Segment Sections... 00 .note.gnu.property 01 .text 02 .note.gnu.property Displaying notes found in: .note.gnu.property Owner Data size Description GNU 0x0010 NT_GNU_PROPERTY_TYPE_0 Properties: x86 ISA used: i486 # ld t.o i.o # readelf -ln a.out Elf file type is EXEC (Executable file) Entry point 0x401000 There are 3 program headers, starting at offset 64 Program Headers: Type Offset VirtAddr PhysAddr FileSizMemSiz Flags Align LOAD 0x1000 0x00401000 0x00401000 0x0001 0x0001 R E0x1000 LOAD 0x2000 0x00402000 0x00402000 0x 0x0008 RW 0x1000 GNU_STACK 0x 0x 0x 0x 0x RWE0x10 Section to Segment mapping: Segment Sections... 00 .text 01 .bss 02 -- You are receiving this mail because: You are on the CC list for the bug. ___ bug-binutils mailing list bug-binutils@gnu.org https://lists.gnu.org/mailman/listinfo/bug-binutils
[Bug ld/23428] ld does not put program headers in a code-only load segment
https://sourceware.org/bugzilla/show_bug.cgi?id=23428 --- Comment #15 from H.J. Lu --- (In reply to nsz from comment #14) > > @Szabolcs: If you rebuild gcc-8 on Debian testing with "--enable-cet=auto" > > added to CONFARGS in debian/rules2, then you should be able to reproduce the > > musl-gcc crash (after removing the --build-id workaround from > > musl-gcc.specs!). > > > > (It appears that "--enable-cet=auto" is the important difference between > > Arch's > > and Debian's GCC packages.) > > thanks, i could reproduce the issue: > > it seems ld tries to add a dummy .note.gnu.property to force the > program headers into a load segment, but if there is already a > .note.gnu.property in some of the input object files then it just > tries to merge those and don't add a dummy note at all, however > the merging rules may produce an empty note in the end and then > the note section is dropped. Please try binutils master branch with commit f7309df20c4e787041cedc4a6aced89c15259e54 Author: H.J. Lu Date: Wed Aug 8 06:09:15 2018 -0700 x86: Properly merge GNU_PROPERTY_X86_ISA_1_USED Without the GNU_PROPERTY_X86_ISA_1_USED property, all ISAs may be used. If a bit in the GNU_PROPERTY_X86_ISA_1_USED property is unset, the corresponding x86 instruction set isn\u2019t used. When merging properties from 2 input files and one input file doesn't have the GNU_PROPERTY_X86_ISA_1_USED property, the output file shouldn't have it neither. This patch removes the GNU_PROPERTY_X86_ISA_1_USED property if an input file doesn't have it. This patch replaces the GNU_PROPERTY_X86_ISA_1_USED property with the GNU_PROPERTY_X86_ISA_1_NEEDED property which is the minimum ISA requirement. -- You are receiving this mail because: You are on the CC list for the bug. ___ bug-binutils mailing list bug-binutils@gnu.org https://lists.gnu.org/mailman/listinfo/bug-binutils
[Bug ld/23428] ld does not put program headers in a code-only load segment
https://sourceware.org/bugzilla/show_bug.cgi?id=23428 --- Comment #16 from Evangelos Foutras --- The test case from comment #14 is still reproducible for me with both binutils master (1dc9e2d6) and binutils-2_31-branch (6ee91b1e). No change at all in the resulting binary, compared to just the patch from comment #4. -- You are receiving this mail because: You are on the CC list for the bug. ___ bug-binutils mailing list bug-binutils@gnu.org https://lists.gnu.org/mailman/listinfo/bug-binutils
[Bug ld/23428] ld does not put program headers in a code-only load segment
https://sourceware.org/bugzilla/show_bug.cgi?id=23428 --- Comment #17 from cvs-commit at gcc dot gnu.org --- The master branch has been updated by H.J. Lu : https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=ab9e342807d132182892de1be1a92d6e91a5c1da commit ab9e342807d132182892de1be1a92d6e91a5c1da Author: H.J. Lu Date: Sat Aug 11 06:41:33 2018 -0700 x86: Properly add X86_ISA_1_NEEDED property Existing properties may be removed during property merging. We avoid adding X86_ISA_1_NEEDED property only if existing properties won't be removed. bfd/ PR ld/23428 * elfxx-x86.c (_bfd_x86_elf_link_setup_gnu_properties): Don't add X86_ISA_1_NEEDED property only if existing properties won't be removed. ld/ PR ld/23428 * testsuite/ld-elf/dummy.s: New file. * testsuite/ld-elf/linux-x86.S: Add X86_FEATURE_1_AND property. * testsuite/ld-elf/linux-x86.exp: Add dummy.s to pr23428. -- You are receiving this mail because: You are on the CC list for the bug. ___ bug-binutils mailing list bug-binutils@gnu.org https://lists.gnu.org/mailman/listinfo/bug-binutils
[Bug ld/23428] ld does not put program headers in a code-only load segment
https://sourceware.org/bugzilla/show_bug.cgi?id=23428 --- Comment #18 from H.J. Lu --- (In reply to Evangelos Foutras from comment #16) > The test case from comment #14 is still reproducible for me with both > binutils master (1dc9e2d6) and binutils-2_31-branch (6ee91b1e). No change at > all in the resulting binary, compared to just the patch from comment #4. Please try master branch again. -- You are receiving this mail because: You are on the CC list for the bug. ___ bug-binutils mailing list bug-binutils@gnu.org https://lists.gnu.org/mailman/listinfo/bug-binutils
[Bug ld/23428] ld does not put program headers in a code-only load segment
https://sourceware.org/bugzilla/show_bug.cgi?id=23428 --- Comment #19 from Evangelos Foutras --- (In reply to H.J. Lu from comment #18) > (In reply to Evangelos Foutras from comment #16) > > The test case from comment #14 is still reproducible for me with both > > binutils master (1dc9e2d6) and binutils-2_31-branch (6ee91b1e). No change at > > all in the resulting binary, compared to just the patch from comment #4. > > Please try master branch again. Your latest commit fixes the issue I was experiencing. Thanks! -- You are receiving this mail because: You are on the CC list for the bug. ___ bug-binutils mailing list bug-binutils@gnu.org https://lists.gnu.org/mailman/listinfo/bug-binutils
[Bug ld/23515] New: Empty GNU_PROPERTY_X86_FEATURE_1_AND isn't removed
https://sourceware.org/bugzilla/show_bug.cgi?id=23515 Bug ID: 23515 Summary: Empty GNU_PROPERTY_X86_FEATURE_1_AND isn't removed Product: binutils Version: 2.32 (HEAD) Status: NEW Severity: normal Priority: P2 Component: ld Assignee: unassigned at sourceware dot org Reporter: hjl.tools at gmail dot com Target Milestone: --- Target: i386,x86-64 [hjl@gnu-tools-1 tmp]$ cat x.s .section ".note.gnu.property", "a" .p2align 2 .long 1f - 0f /* name length */ .long 5f - 2f /* data length */ .long 5 /* note type */ 0: .asciz "GNU"/* vendor name */ 1: .p2align 2 2: .long 0xc002/* pr_type. */ .long 4f - 3f /* pr_datasz. */ 3: .long 0x0 4: .p2align 2 5: [hjl@gnu-tools-1 tmp]$ gcc -c -m32 x.s [hjl@gnu-tools-1 tmp]$ ld -shared -m elf_i386 x.o [hjl@gnu-tools-1 tmp]$ readelf -n x.o Displaying notes found in: .note.gnu.property Owner Data size Description GNU 0x000c NT_GNU_PROPERTY_TYPE_0 Properties: x86 feature: [hjl@gnu-tools-1 tmp]$ -- You are receiving this mail because: You are on the CC list for the bug. ___ bug-binutils mailing list bug-binutils@gnu.org https://lists.gnu.org/mailman/listinfo/bug-binutils
