[binutils-gdb] RISC-V: Segment fault for kernel purgatory when linking.

[Nelson Chu]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=1d7a877a0f74a7b90d70ca8cc3c0db9461619b1a

commit 1d7a877a0f74a7b90d70ca8cc3c0db9461619b1a
Author: Nelson Chu <nelson@rivosinc.com>
Date:   Mon Apr 29 17:44:51 2024 +0800

    RISC-V: Segment fault for kernel purgatory when linking.
    
    This was originally reported by Ard Biesheuvel <ardb@kernel.org>.
    
    The followings are reproduce steps,
    https://lore.kernel.org/all/202404260640.9GQVTmrw-lkp@intel.com/T/#u
    
    The segment fault happens in the riscv_elf_finish_dynamic_sections when the
    output got section is an ABS.  Refer to MIPS code, they added an extra
    bfd_is_abs_section check to avoid ABS got, so this seems the right and easier
    way to go in the short-term.
    
    bfd/
            * elfnn-riscv.c (riscv_elf_finish_dynamic_sections): Set sh_entsize
            and fill the got entries only when the got isn't an ABS section, and
            the size of got is larger than zero.  The similar goes for gotplt,
            except we already reported error when the gotplt is an ABS.

Diff:
---
 bfd/elfnn-riscv.c | 23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/bfd/elfnn-riscv.c b/bfd/elfnn-riscv.c
index 604f6de4511..3fc87267f30 100644
--- a/bfd/elfnn-riscv.c
+++ b/bfd/elfnn-riscv.c
@@ -3569,7 +3569,7 @@ riscv_elf_finish_dynamic_sections (bfd *output_bfd,
 	}
     }
 
-  if (htab->elf.sgotplt)
+  if (htab->elf.sgotplt && htab->elf.sgotplt->size > 0)
     {
       asection *output_section = htab->elf.sgotplt->output_section;
 
@@ -3580,31 +3580,28 @@ riscv_elf_finish_dynamic_sections (bfd *output_bfd,
 	  return false;
 	}
 
-      if (htab->elf.sgotplt->size > 0)
-	{
-	  /* Write the first two entries in .got.plt, needed for the dynamic
-	     linker.  */
-	  bfd_put_NN (output_bfd, (bfd_vma) -1, htab->elf.sgotplt->contents);
-	  bfd_put_NN (output_bfd, (bfd_vma) 0,
-		      htab->elf.sgotplt->contents + GOT_ENTRY_SIZE);
-	}
+      /* Write the first two entries in .got.plt, needed for the dynamic
+	 linker.  */
+      bfd_put_NN (output_bfd, (bfd_vma) -1, htab->elf.sgotplt->contents);
+      bfd_put_NN (output_bfd, (bfd_vma) 0,
+		  htab->elf.sgotplt->contents + GOT_ENTRY_SIZE);
 
       elf_section_data (output_section)->this_hdr.sh_entsize = GOT_ENTRY_SIZE;
     }
 
-  if (htab->elf.sgot)
+  if (htab->elf.sgot && htab->elf.sgot->size > 0)
     {
       asection *output_section = htab->elf.sgot->output_section;
 
-      if (htab->elf.sgot->size > 0)
+      if (!bfd_is_abs_section (output_section))
 	{
 	  /* Set the first entry in the global offset table to the address of
 	     the dynamic section.  */
 	  bfd_vma val = sdyn ? sec_addr (sdyn) : 0;
 	  bfd_put_NN (output_bfd, val, htab->elf.sgot->contents);
-	}
 
-      elf_section_data (output_section)->this_hdr.sh_entsize = GOT_ENTRY_SIZE;
+	  elf_section_data (output_section)->this_hdr.sh_entsize = GOT_ENTRY_SIZE;
+	}
     }
 
   /* Fill PLT and GOT entries for local STT_GNU_IFUNC symbols.  */