tree 0f735a38353f254e2d415664fcf783d545cba23e
parent ef37bc361442545a5be3c56c49a08c3153032127
author Andy Lutomirski <luto@kernel.org> 1490218349 -0700
committer Ingo Molnar <mingo@kernel.org> 1490253907 +0100

selftests/x86/ldt_gdt_32: Work around a glibc sigaction() bug

i386 glibc is buggy and calls the sigaction syscall incorrectly.

This is asymptomatic for normal programs, but it blows up on
programs that do evil things with segmentation.  The ldt_gdt
self-test is an example of such an evil program.

This doesn't appear to be a regression -- I think I just got lucky
with the uninitialized memory that glibc threw at the kernel when I
wrote the test.

This hackish fix manually issues sigaction(2) syscalls to undo the
damage.  Without the fix, ldt_gdt_32 segfaults; with the fix, it
passes for me.

See: https://sourceware.org/bugzilla/show_bug.cgi?id=21269

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/aaab0f9f93c9af25396f01232608c163a760a668.1490218061.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>