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

selftests/powerpc: Fix TM resched DSCR test with some compilers

to the 4.9-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-powerpc-fix-tm-resched-dscr-test-with-some-compilers.patch and it can be found in the queue-4.9 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 Mon Apr 9 17:09:24 CEST 2018

From: Michael Ellerman mpe@ellerman.id.au Date: Fri, 19 May 2017 11:29:04 +1000 Subject: selftests/powerpc: Fix TM resched DSCR test with some compilers

From: Michael Ellerman mpe@ellerman.id.au

[ Upstream commit fe06fe860250a4f01d0eaf70a2563b1997174a74 ]

The tm-resched-dscr test has started failing sometimes, depending on what compiler it's built with, eg:

test: tm_resched_dscr Check DSCR TM context switch: tm-resched-dscr: tm-resched-dscr.c:76: test_body: Assertion `rv' failed. !! child died by signal 6

When it fails we see that the compiler doesn't initialise rv to 1 before entering the inline asm block. Although that's counter intuitive, it is allowed because we tell the compiler that the inline asm will write to rv (using "=r"), meaning the original value is irrelevant.

Marking it as a read/write parameter would presumably work, but it seems simpler to fix it by setting the initial value of rv in the inline asm.

Fixes: 96d016108640 ("powerpc: Correct DSCR during TM context switch") Signed-off-by: Michael Ellerman mpe@ellerman.id.au Acked-by: Michael Neuling mikey@neuling.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/testing/selftests/powerpc/tm/tm-resched-dscr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c +++ b/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c @@ -42,12 +42,12 @@ int test_body(void) printf("Check DSCR TM context switch: "); fflush(stdout); for (;;) { - rv = 1; asm __volatile__ ( /* set a known value into the DSCR */ "ld 3, %[dscr1];" "mtspr %[sprn_dscr], 3;"

+ "li %[rv], 1;" /* start and suspend a transaction */ "tbegin.;" "beq 1f;"

Patches currently in stable-queue which might be from mpe@ellerman.id.au are

queue-4.9/selftests-powerpc-fix-tm-resched-dscr-test-with-some-compilers.patch queue-4.9/powerpc-modules-if-mprofile-kernel-is-enabled-add-it-to-vermagic.patch queue-4.9/powerpc-mm-fix-virt_addr_valid-etc.-on-64-bit-hash.patch queue-4.9/powerpc-spufs-fix-coredump-of-spu-contexts.patch queue-4.9/cxl-unlock-on-error-in-probe.patch queue-4.9/signal-powerpc-document-conflicts-with-si_user-and-sigfpe-and-sigtrap.patch queue-4.9/powerpc-don-t-clobber-tcr-when-setting-tcr.patch queue-4.9/powerpc-8xx-fix-mpc8xx_get_irq-return-on-no-irq.patch