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From: "fweimer at redhat dot com" <sourceware-bugzilla@sourceware.org>
To: glibc-bugs@sourceware.org
Subject: [Bug dynamic-link/31501] New: _dl_tlsdesc_dynamic_xsavec may clobber
 %rbx
Date: Sat, 16 Mar 2024 14:23:18 +0000
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https://sourceware.org/bugzilla/show_bug.cgi?id=3D31501

            Bug ID: 31501
           Summary: _dl_tlsdesc_dynamic_xsavec may clobber %rbx
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: dynamic-link
          Assignee: fweimer at redhat dot com
          Reporter: fweimer at redhat dot com
  Target Milestone: ---
            Target: x86-64

I believe the stack realignment code in sysdeps/x86_64/dl-tlsdesc-dynamic.h=
 can
clobber the initial set of saved registers (including %rbx) if the stack
alignment is unfortunate. The stack pointer is aligned down without first
decrementing it, so the created stack area can partially overlap with the p=
art
of the red zone that was used for the initial register save.

--=20
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