Pawan Gupta 7f06caaae0 x86/entry_32: Do not clobber user EFLAGS.ZF
commit 2e2e5143d4868163d6756c8c6a4d28cbfa5245e5 upstream.

Opportunistic SYSEXIT executes VERW to clear CPU buffers after user EFLAGS
are restored. This can clobber user EFLAGS.ZF.

Move CLEAR_CPU_BUFFERS before the user EFLAGS are restored. This ensures
that the user EFLAGS.ZF is not clobbered.

Closes: https://lore.kernel.org/lkml/yVXwe8gvgmPADpRB6lXlicS2fcHoV5OHHxyuFbB_MEleRPD7-KhGe5VtORejtPe-KCkT8Uhcg5d7-IBw4Ojb4H7z5LQxoZylSmJ8KNL3A8o=@protonmail.com/
Fixes: a0e2dab44d22 ("x86/entry_32: Add VERW just before userspace transition")
Reported-by: Jari Ruusu <jariruusu@protonmail.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc:stable@vger.kernel.org
Link: https://lore.kernel.org/all/20240925-fix-dosemu-vm86-v7-1-1de0daca2d42%40linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-10-22 15:56:50 +02:00
2024-10-22 15:56:43 +02:00
2022-09-28 09:02:20 +02:00
2024-10-17 15:22:28 +02:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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