Messages in this thread | | | From | Jann Horn <> | Date | Wed, 23 Dec 2020 07:55:20 +0100 | Subject | Re: [PATCH v3 3/4] x86/signal: Prevent an alternate stack overflow before a signal delivery |
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On Wed, Dec 23, 2020 at 2:57 AM Chang S. Bae <chang.seok.bae@intel.com> wrote: > The kernel pushes data on the userspace stack when entering a signal. If > using a sigaltstack(), the kernel precisely knows the user stack size. > > When the kernel knows that the user stack is too small, avoid the overflow > and do an immediate SIGSEGV instead. > > This overflow is known to occur on systems with large XSAVE state. The > effort to increase the size typically used for altstacks reduces the > frequency of these overflows, but this approach is still useful for legacy > binaries. > > Suggested-by: Jann Horn <jannh@google.com> > Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com> > Reviewed-by: Len Brown <len.brown@intel.com> > Cc: Jann Horn <jannh@google.com> > Cc: x86@kernel.org > Cc: linux-kernel@vger.kernel.org
Reviewed-by: Jann Horn <jannh@google.com>
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