[Bug ld/19807] New: [2.26 regression] R_386_GOT32X optimization breaks linux kernel
https://sourceware.org/bugzilla/show_bug.cgi?id=19807 Bug ID: 19807 Summary: [2.26 regression] R_386_GOT32X optimization breaks linux kernel Product: binutils Version: 2.27 (HEAD) Status: NEW Severity: critical Priority: P2 Component: ld Assignee: unassigned at sourceware dot org Reporter: fvogt at suse dot com Target Milestone: --- Building the i386 linux kernel (tried the latest 4.5 rc7, but all are broken) with compression causes booting to fail during the decompression stage: "Failed to allocate space for phdrs". The kernel decompressor stage is linked to a fixed address, but running at a different location. This isn't a problem as it relocates itself by adding the difference to the GOT entries, but the optimization "mov $GOTOFF(%ecx), %eax" (R_386_GOT32X) -> "lea $address, %eax" (R_386_32) breaks this, as the GOT is no longer referenced in the final ELF. Result is that some global variables, like free_mem_ptr_end, are overwritten during decompression, causing weird errors like malloc returing NULL. Workaround: specify "--disable-x86-relax-relocations" configure option or "-mrelax-relocations=no" to as. See also: https://bugzilla.opensuse.org/show_bug.cgi?id=970239 https://bugzilla.redhat.com/show_bug.cgi?id=1302071 -- 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/19807] [2.26 regression] R_386_GOT32X optimization breaks linux kernel
https://sourceware.org/bugzilla/show_bug.cgi?id=19807 --- Comment #2 from Fabian Vogt --- I tried that but it crashed even before the decompressor. I'll have a closer look at that and report back. -- 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/19807] [2.26 regression] R_386_GOT32X optimization breaks linux kernel
https://sourceware.org/bugzilla/show_bug.cgi?id=19807 Fabian Vogt changed: What|Removed |Added Status|WAITING |ASSIGNED --- Comment #6 from Fabian Vogt --- (In reply to H.J. Lu from comment #5) > Created attachment 9089 [details] > An updated patch to pass --no-dynamic-linker to linker Applied and tested with 4.5rc7. Result: Boots fine! -- 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/19807] [2.26 regression] R_386_GOT32X optimization breaks linux kernel
https://sourceware.org/bugzilla/show_bug.cgi?id=19807 --- Comment #9 from Fabian Vogt --- I just tested your patch again on a clean kernel tree, it seems that my previous test was somehow wrong. Using "-pie" as flag to LD causes leal(_bss-4)(%ebp), %esi leal(_bss-4)(%ebx), %edi in arch/x86/boot/compressed/head_32.S to be leal-0x4(%ebp), %esi leal-0x4(%ebx), %edi instead of the expected leal0x59a27c(%ebp),%esi leal0x59a27c(%ebx),%edi so the kernel does not copy itself correctly. -- 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/19807] [2.26 regression] R_386_GOT32X optimization breaks linux kernel
https://sourceware.org/bugzilla/show_bug.cgi?id=19807 --- Comment #10 from Fabian Vogt --- (In reply to Fabian Vogt from comment #9) > I just tested your patch again on a clean kernel tree, it seems that my > previous test was somehow wrong. Actually, I just tried with binutils master instead of 2.26 again and it works. Is there anything that can be used to get this working with 2.26? -- 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/19807] [2.26 regression] R_386_GOT32X optimization breaks linux kernel
https://sourceware.org/bugzilla/show_bug.cgi?id=19807 --- Comment #12 from Fabian Vogt --- (In reply to H.J. Lu from comment #11) > (In reply to Fabian Vogt from comment #10) > > (In reply to Fabian Vogt from comment #9) > > > I just tested your patch again on a clean kernel tree, it seems that my > > > previous test was somehow wrong. > > > > Actually, I just tried with binutils master instead of 2.26 again and it > > works. > > Is there anything that can be used to get this working with 2.26? > > Did you mean binutils 2.26 branch or 2.26 release? > ld -v GNU ld (GNU Binutils; openSUSE Factory) 2.26.0.20160229-1 which is the 2.26 branch up to 4eb4e2ad76eb4bf5a2a2c20b2a2ec382fdbb3e2f. -- 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/19807] [2.26 regression] R_386_GOT32X optimization breaks linux kernel
https://sourceware.org/bugzilla/show_bug.cgi?id=19807 --- Comment #14 from Fabian Vogt --- I could reproduce the issue with GNU ld (GNU Binutils) 2.26.0.20160314 as well. For the difference, see comment 9. -- 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/19807] [2.26 regression] R_386_GOT32X optimization breaks linux kernel
https://sourceware.org/bugzilla/show_bug.cgi?id=19807 --- Comment #16 from Fabian Vogt --- (In reply to H.J. Lu from comment #15) > (In reply to Fabian Vogt from comment #14) > > I could reproduce the issue with > > > > GNU ld (GNU Binutils) 2.26.0.20160314 > > > > as well. For the difference, see comment 9. > > Please try users/hjl/dynamic/binutils-2_26-branch branch. Works fine. -- 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/19807] [2.26 regression] R_386_GOT32X optimization breaks linux kernel
https://sourceware.org/bugzilla/show_bug.cgi?id=19807 Fabian Vogt changed: What|Removed |Added Status|RESOLVED|REOPENED Resolution|FIXED |--- --- Comment #21 from Fabian Vogt --- (In reply to Richard Guenther from comment #20) > Hum, so we leave 2.26 broken? The 2.26 release is not broken, "only" the binutils-2_26-branch. Reopening to request clarification whether and how that can be solved. -- 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/19807] [2.26 regression] R_386_GOT32X optimization breaks linux kernel
https://sourceware.org/bugzilla/show_bug.cgi?id=19807 --- Comment #24 from Fabian Vogt --- (In reply to H.J. Lu from comment #23) > (In reply to Richard Guenther from comment #20) > > Hum, so we leave 2.26 broken? > > Please try users/hjl/pr19827/binutils-2_26-branch branch. Tested and boots. -- 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
