在 2025/6/19 10:26, Shuai Xue 写道:

在 2025/6/19 05:36, Shuah Khan 写道:

quoted

On 6/15/25 23:06, Shuai Xue wrote:

quoted

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:

quoted

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@linux.alibaba.com>
---

Assuming this is going through Christian's tree.

Acked-by: Shuah Khan <skhan@linuxfoundation.org>

Let me know if you would like me to pick it up.

thanks,
-- Shuah

Hi, Shuah

Thanks for your review.

I send this fix in Mar, but it missed last linux version.
I think I need your help to pick it up.

Thanks.
Shuai

Hi, Shuah,

Gentle ping,

Thanks.
Shuai