* [PATCH v2] rseq/selftests: fix parametrized test with -fpie
@ 2018-09-27 18:39 Mathieu Desnoyers
2018-09-27 19:12 ` Shuah Khan
0 siblings, 1 reply; 2+ messages in thread
From: Mathieu Desnoyers @ 2018-09-27 18:39 UTC (permalink / raw)
To: Shuah Khan
Cc: linux-kernel, Mathieu Desnoyers, stable, Thomas Gleixner,
Joel Fernandes, Peter Zijlstra, Catalin Marinas, Dave Watson,
Will Deacon, Andi Kleen, linux-kselftest, H . Peter Anvin,
Chris Lameter, Russell King, Michael Kerrisk, Paul E . McKenney,
Paul Turner, Boqun Feng, Josh Triplett, Steven Rostedt,
Ben Maurer, Andy Lutomirski, Andrew Morton, Linus Torvalds
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>
---
Changes since v1:
- Update email address for Shuah Khan based on updated MAINTAINERS
email address,
- Rebase on v4.19-rc5.
---
tools/testing/selftests/rseq/param_test.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)
diff --git a/tools/testing/selftests/rseq/param_test.c b/tools/testing/selftests/rseq/param_test.c
index 642d4e12abea..eec2663261f2 100644
--- 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(__s390__)
#define RSEQ_INJECT_INPUT \
--
2.17.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] rseq/selftests: fix parametrized test with -fpie
2018-09-27 18:39 [PATCH v2] rseq/selftests: fix parametrized test with -fpie Mathieu Desnoyers
@ 2018-09-27 19:12 ` Shuah Khan
0 siblings, 0 replies; 2+ messages in thread
From: Shuah Khan @ 2018-09-27 19:12 UTC (permalink / raw)
To: Mathieu Desnoyers
Cc: linux-kernel, stable, Thomas Gleixner, Joel Fernandes,
Peter Zijlstra, Catalin Marinas, Dave Watson, Will Deacon,
Andi Kleen, linux-kselftest, H . Peter Anvin, Chris Lameter,
Russell King, Michael Kerrisk, Paul E . McKenney, Paul Turner,
Boqun Feng, Josh Triplett, Steven Rostedt, Ben Maurer,
Andy Lutomirski, Andrew Morton, Linus Torvalds, Shuah Khan
On 09/27/2018 12:39 PM, Mathieu Desnoyers wrote:
> 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>
> ---
> Changes since v1:
> - Update email address for Shuah Khan based on updated MAINTAINERS
> email address,
> - Rebase on v4.19-rc5.
> ---
> tools/testing/selftests/rseq/param_test.c | 19 ++++++++++---------
> 1 file changed, 10 insertions(+), 9 deletions(-)
>
> diff --git a/tools/testing/selftests/rseq/param_test.c b/tools/testing/selftests/rseq/param_test.c
> index 642d4e12abea..eec2663261f2 100644
> --- 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(__s390__)
>
> #define RSEQ_INJECT_INPUT \
>
Applied now to linux-kselftest fixes. I will get this into the next rc
thanks,
-- Shuah
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