Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux

rseq/selftests: fix parametrized test with -fpie

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>

authored by

Mathieu Desnoyers and committed by
Shuah Khan (Samsung OSG)
ce01a157 7876320f

+10 -9
+10 -9
tools/testing/selftests/rseq/param_test.c
··· 56 56 printf(fmt, ## __VA_ARGS__); \ 57 57 } while (0) 58 58 59 - #if defined(__x86_64__) || defined(__i386__) 59 + #ifdef __i386__ 60 60 61 61 #define INJECT_ASM_REG "eax" 62 62 63 63 #define RSEQ_INJECT_CLOBBER \ 64 64 , INJECT_ASM_REG 65 - 66 - #ifdef __i386__ 67 65 68 66 #define RSEQ_INJECT_ASM(n) \ 69 67 "mov asm_loop_cnt_" #n ", %%" INJECT_ASM_REG "\n\t" \ ··· 74 76 75 77 #elif defined(__x86_64__) 76 78 79 + #define INJECT_ASM_REG_P "rax" 80 + #define INJECT_ASM_REG "eax" 81 + 82 + #define RSEQ_INJECT_CLOBBER \ 83 + , INJECT_ASM_REG_P \ 84 + , INJECT_ASM_REG 85 + 77 86 #define RSEQ_INJECT_ASM(n) \ 78 - "lea asm_loop_cnt_" #n "(%%rip), %%" INJECT_ASM_REG "\n\t" \ 79 - "mov (%%" INJECT_ASM_REG "), %%" INJECT_ASM_REG "\n\t" \ 87 + "lea asm_loop_cnt_" #n "(%%rip), %%" INJECT_ASM_REG_P "\n\t" \ 88 + "mov (%%" INJECT_ASM_REG_P "), %%" INJECT_ASM_REG "\n\t" \ 80 89 "test %%" INJECT_ASM_REG ",%%" INJECT_ASM_REG "\n\t" \ 81 90 "jz 333f\n\t" \ 82 91 "222:\n\t" \ 83 92 "dec %%" INJECT_ASM_REG "\n\t" \ 84 93 "jnz 222b\n\t" \ 85 94 "333:\n\t" 86 - 87 - #else 88 - #error "Unsupported architecture" 89 - #endif 90 95 91 96 #elif defined(__s390__) 92 97