Messages in this thread | | | Subject | Re: [PATCH] x86/selftests: add clobbers for int80 on x86_64 | From | Dmitry Safonov <> | Date | Fri, 10 Feb 2017 14:57:04 +0300 |
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On 02/10/2017 02:52 PM, Dmitry Safonov wrote: > Kernel erases R8..R11 registers prior returning to userspace > from int80: https://lkml.org/lkml/2009/10/1/164 > > GCC can reuse this registers and doesn't expect them to change > during syscall invocation. I met this kind of bug in CRIU once > gcc 6.1 and clang stored local variables in those registers > and the kernel zerofied them during syscall: > https://github.com/xemul/criu/commit/990d33f1a1cdd17bca6c2eb059ab3be2564f7fa2 > > By that reason I suggest to add those registers to clobbers > in selftests. > > Cc: Shuah Khan <shuah@kernel.org> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: "H. Peter Anvin" <hpa@zytor.com> > Cc: Andy Lutomirski <luto@kernel.org> > Cc: Borislav Petkov <bp@suse.de> > Cc: x86@kernel.org > Cc: linux-kselftest@vger.kernel.org > Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com> > --- > tools/testing/selftests/x86/fsgsbase.c | 2 +- > tools/testing/selftests/x86/iopl.c | 10 ++++++++--
Drop this one: iopl doesn't do int80 - it's my failure in grepping. Will resend.
> tools/testing/selftests/x86/ldt_gdt.c | 16 +++++++++++----- > tools/testing/selftests/x86/ptrace_syscall.c | 3 ++- > tools/testing/selftests/x86/single_step_syscall.c | 5 ++++- > 5 files changed, 26 insertions(+), 10 deletions(-) >
-- Dmitry
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