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gdb: fix possible uninitialised variable use

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After this commit:

  commit 198ff6ff81
  Date:   Tue Jan 30 15:37:23 2024 +0000

      gdb/gdbserver: share x86/linux tdesc caching

a possible use of an uninitialised variable was introduced, the
'tdesc' variable in i386_linux_core_read_description might be read
without being written too if 'xcr0' was 0.

This is fixed in this commit.  I've updated the function to follow the
same pattern as amd64_linux_core_read_description, if xcr0 is 0 then
we select a default xcr0 value and use that to select a tdesc.
This commit is contained in:
Andrew Burgess
2024-03-26 12:05:07 +00:00
parent c7c9820071
commit 24df37a10f
1 changed files with 8 additions and 10 deletions
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18
gdb/i386-linux-tdep.c
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@@ -700,17 +700,15 @@ i386_linux_core_read_description (struct gdbarch *gdbarch,
x86_xsave_layout layout; x86_xsave_layout layout;
uint64_t xcr0 = i386_linux_core_read_xsave_info (abfd, layout); uint64_t xcr0 = i386_linux_core_read_xsave_info (abfd, layout);
const struct target_desc *tdesc; if (xcr0 == 0)
if (xcr0 != 0) {
tdesc = i386_linux_read_description (xcr0); if (bfd_get_section_by_name (abfd, ".reg-xfp") != nullptr)
xcr0 = X86_XSTATE_SSE_MASK;
if (tdesc != NULL)
return tdesc;
if (bfd_get_section_by_name (abfd, ".reg-xfp") != NULL)
return i386_linux_read_description (X86_XSTATE_SSE_MASK);
else else
return i386_linux_read_description (X86_XSTATE_X87_MASK); xcr0 = X86_XSTATE_X87_MASK;
}
return i386_linux_read_description (xcr0);
} }
/* Similar to i386_supply_fpregset, but use XSAVE extended state. */ /* Similar to i386_supply_fpregset, but use XSAVE extended state. */