55617fb991
The INT 0x80 instruction is used for 32-bit x86 Linux syscalls. The kernel expects to receive a software interrupt as a result of the INT 0x80 instruction. However, an external interrupt on the same vector also triggers the same codepath. An external interrupt on vector 0x80 will currently be interpreted as a 32-bit system call, and assuming that it was a user context. Panic on external interrupts on the vector. To distinguish software interrupts from external ones, the kernel checks the APIC ISR bit relevant to the 0x80 vector. For software interrupts, this bit will be 0. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de> Cc: <stable@vger.kernel.org> # v6.0+
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.