The pidfd_test fails on the ARM64 platform with the following error:
Bail out! pidfd_poll check for premature notification on child thread exec test: Failed
When exception-trace is enabled, the kernel logs the details:
#echo 1 > /proc/sys/debug/exception-trace
#dmesg | tail -n 20
[48628.713023] pidfd_test[1082142]: unhandled exception: SP Alignment, ESR 0x000000009a000000, SP/PC alignment exception in pidfd_test[400000+4000]
[48628.713049] CPU: 21 PID: 1082142 Comm: pidfd_test Kdump: loaded Tainted: G W E 6.6.71-3_rc1.al8.aarch64 #1
[48628.713051] Hardware name: AlibabaCloud AliServer-Xuanwu2.0AM-1UC1P-5B/AS1111MG1, BIOS 1.2.M1.AL.P.157.00 07/29/2023
[48628.713053] pstate: 60001800 (nZCv daif -PAN -UAO -TCO -DIT +SSBS BTYPE=-c)
[48628.713055] pc : 0000000000402100
[48628.713056] lr : 0000ffff98288f9c
[48628.713056] sp : 0000ffffde49daa8
[48628.713057] x29: 0000000000000000 x28: 0000000000000000 x27: 0000000000000000
[48628.713060] x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000
[48628.713062] x23: 0000000000000000 x22: 0000000000000000 x21: 0000000000400e80
[48628.713065] x20: 0000000000000000 x19: 0000000000402650 x18: 0000000000000000
[48628.713067] x17: 00000000004200d8 x16: 0000ffff98288f40 x15: 0000ffffde49b92c
[48628.713070] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000
[48628.713072] x11: 0000000000001011 x10: 0000000000402100 x9 : 0000000000000010
[48628.713074] x8 : 00000000000000dc x7 : 3861616239346564 x6 : 000000000000000a
[48628.713077] x5 : 0000ffffde49daa8 x4 : 000000000000000a x3 : 0000ffffde49daa8
[48628.713079] x2 : 0000ffffde49dadc x1 : 0000ffffde49daa8 x0 : 0000000000000000
According to ARM ARM D1.3.10.2 SP alignment checking:
> When the SP is used as the base address of a calculation, regardless of
> any offset applied by the instruction, if bits [3:0] of the SP are not
> 0b0000, there is a misaligned SP.
To fix it, align the stack with 16 bytes.
Signed-off-by: Shuai Xue <xueshuai@xxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/pidfd/pidfd_test.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/pidfd/pidfd_test.c b/tools/testing/selftests/pidfd/pidfd_test.c
index c081ae91313a..ec161a7c3ff9 100644
--- a/tools/testing/selftests/pidfd/pidfd_test.c
+++ b/tools/testing/selftests/pidfd/pidfd_test.c
@@ -33,7 +33,7 @@ static bool have_pidfd_send_signal;
static pid_t pidfd_clone(int flags, int *pidfd, int (*fn)(void *))
{
size_t stack_size = 1024;
- char *stack[1024] = { 0 };
+ char *stack[1024] __attribute__((aligned(16))) = {0};
#ifdef __ia64__
return __clone2(fn, stack, stack_size, flags | SIGCHLD, NULL, pidfd);
--
2.39.3
