On Mon, Mar 21, 2016 at 07:23:28PM +0800, Zhangjian (Bamvor) wrote:

quoted

quoted

So this most probably means that ilp32 code doesn't handle one of cloned
item properly. I have already discovered a bug where child processes
used parent TLS,

It is a kernel bug or glibc bug? Could you please explain it or show the patch?
The current ILP32 patches looks good to me. Recently, I backport these patches
to our 4.1 kernel. And I saw crash frequently even if I only do a single print
or infinite loop. There is some small changes about tls register after 4.1. I
am not sure if it is a similar issue. It is great if you have some suggestions/
ideas.

My issue is because I forget to change is_compat_task to
is_a32_compat_task in arch/arm64/kernel/process.c such piece of code
is delete after commit d00a3810c162 ("arm64: context-switch user tls
register tpidr_el0 for compat tasks). It is not exist in upstream
kernel, never mind.

Meanwhile, I found that it seem that there is another is_compat_task
in tls_thread_flush. Is it relative the issue you mentioned?

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 432b094..9ab968c 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -209,7 +209,7 @@ static void tls_thread_flush(void)
 {
        asm ("msr tpidr_el0, xzr");

-       if (is_compat_task()) {
+       if (is_a32_compat_task()) {
                current->thread.tp_value = 0;

                /*

Regards

Bamvor

Hi,

This fix looks correct, though doesn't fix issue.
Thank you.

Yury.