This is a note to let you know that I've just added the patch titled

selftests/x86/ldt_get: Add a few additional tests for limits

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: selftests-x86-ldt_get-add-a-few-additional-tests-for-limits.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Wed Dec 6 16:43:17 CET 2017

From: Andy Lutomirski luto@kernel.org Date: Sat, 4 Nov 2017 04:19:52 -0700 Subject: selftests/x86/ldt_get: Add a few additional tests for limits

From: Andy Lutomirski luto@kernel.org

[ Upstream commit fec8f5ae1715a01c72ad52cb2ecd8aacaf142302 ]

We weren't testing the .limit and .limit_in_pages fields very well. Add more tests.

This addition seems to trigger the "bits 16:19 are undefined" issue that was fixed in an earlier patch. I think that, at least on my CPU, the high nibble of the limit ends in LAR bits 16:19.

Signed-off-by: Andy Lutomirski luto@kernel.org Cc: Borislav Petkov bpetkov@suse.de Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Link: http://lkml.kernel.org/r/5601c15ea9b3113d288953fd2838b18bedf6bc67.1509794321... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/testing/selftests/x86/ldt_gdt.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-)

--- a/tools/testing/selftests/x86/ldt_gdt.c +++ b/tools/testing/selftests/x86/ldt_gdt.c @@ -351,9 +351,24 @@ static void do_simple_tests(void) install_invalid(&desc, false);

desc.seg_not_present = 0; - desc.read_exec_only = 0; desc.seg_32bit = 1; + desc.read_exec_only = 0; + desc.limit = 0xfffff; + install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S | AR_P | AR_DB); + + desc.limit_in_pages = 1; + + install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S | AR_P | AR_DB | AR_G); + desc.read_exec_only = 1; + install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA | AR_S | AR_P | AR_DB | AR_G); + desc.contents = 1; + desc.read_exec_only = 0; + install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA_EXPDOWN | AR_S | AR_P | AR_DB | AR_G); + desc.read_exec_only = 1; + install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA_EXPDOWN | AR_S | AR_P | AR_DB | AR_G); + + desc.limit = 0; install_invalid(&desc, true); }

Patches currently in stable-queue which might be from luto@kernel.org are

queue-4.4/selftests-x86-ldt_get-add-a-few-additional-tests-for-limits.patch queue-4.4/x86-entry-use-syscall_define-macros-for-sys_modify_ldt.patch