4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Mathieu Desnoyers mathieu.desnoyers@efficios.com

commit ce01a1575f45bf319e374592656441021a7f5823 upstream.

On x86-64, the parametrized selftest code for rseq crashes with a segmentation fault when compiled with -fpie. This happens when the param_test binary is loaded at an address beyond 32-bit on x86-64.

The issue is caused by use of a 32-bit register to hold the address of the loop counter variable.

Fix this by using a 64-bit register to calculate the address of the loop counter variables as an offset from rip.

Signed-off-by: Mathieu Desnoyers mathieu.desnoyers@efficios.com Acked-by: "Paul E . McKenney" paulmck@linux.vnet.ibm.com Cc: stable@vger.kernel.org # v4.18 Cc: Shuah Khan shuah@kernel.org Cc: Thomas Gleixner tglx@linutronix.de Cc: Joel Fernandes joelaf@google.com Cc: Peter Zijlstra peterz@infradead.org Cc: Catalin Marinas catalin.marinas@arm.com Cc: Dave Watson davejwatson@fb.com Cc: Will Deacon will.deacon@arm.com Cc: Andi Kleen andi@firstfloor.org Cc: linux-kselftest@vger.kernel.org Cc: "H . Peter Anvin" hpa@zytor.com Cc: Chris Lameter cl@linux.com Cc: Russell King linux@arm.linux.org.uk Cc: Michael Kerrisk mtk.manpages@gmail.com Cc: "Paul E . McKenney" paulmck@linux.vnet.ibm.com Cc: Paul Turner pjt@google.com Cc: Boqun Feng boqun.feng@gmail.com Cc: Josh Triplett josh@joshtriplett.org Cc: Steven Rostedt rostedt@goodmis.org Cc: Ben Maurer bmaurer@fb.com Cc: Andy Lutomirski luto@amacapital.net Cc: Andrew Morton akpm@linux-foundation.org Cc: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Shuah Khan (Samsung OSG) shuah@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- tools/testing/selftests/rseq/param_test.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-)

--- a/tools/testing/selftests/rseq/param_test.c +++ b/tools/testing/selftests/rseq/param_test.c @@ -56,15 +56,13 @@ unsigned int yield_mod_cnt, nr_abort; printf(fmt, ## __VA_ARGS__); \ } while (0)

-#if defined(__x86_64__) || defined(__i386__) +#ifdef __i386__

#define INJECT_ASM_REG "eax"

#define RSEQ_INJECT_CLOBBER \ , INJECT_ASM_REG

-#ifdef __i386__ - #define RSEQ_INJECT_ASM(n) \ "mov asm_loop_cnt_" #n ", %%" INJECT_ASM_REG "\n\t" \ "test %%" INJECT_ASM_REG ",%%" INJECT_ASM_REG "\n\t" \ @@ -76,9 +74,16 @@ unsigned int yield_mod_cnt, nr_abort;

#elif defined(__x86_64__)

+#define INJECT_ASM_REG_P "rax" +#define INJECT_ASM_REG "eax" + +#define RSEQ_INJECT_CLOBBER \ + , INJECT_ASM_REG_P \ + , INJECT_ASM_REG + #define RSEQ_INJECT_ASM(n) \ - "lea asm_loop_cnt_" #n "(%%rip), %%" INJECT_ASM_REG "\n\t" \ - "mov (%%" INJECT_ASM_REG "), %%" INJECT_ASM_REG "\n\t" \ + "lea asm_loop_cnt_" #n "(%%rip), %%" INJECT_ASM_REG_P "\n\t" \ + "mov (%%" INJECT_ASM_REG_P "), %%" INJECT_ASM_REG "\n\t" \ "test %%" INJECT_ASM_REG ",%%" INJECT_ASM_REG "\n\t" \ "jz 333f\n\t" \ "222:\n\t" \ @@ -86,10 +91,6 @@ unsigned int yield_mod_cnt, nr_abort; "jnz 222b\n\t" \ "333:\n\t"

-#else -#error "Unsupported architecture" -#endif - #elif defined(__ARMEL__)

#define RSEQ_INJECT_INPUT \