[LTP] [EXT] Re: [PATCH v9 00/24] ILP32 for ARM64

[LTP] [EXT] Re: [PATCH v9 00/24] ILP32 for ARM64

[Yuri Norov]

+ ltp@lists.linux.it

> There is a problem with the stack size accounting during execve when
> there is no stack limit:
>
> $ ulimit -s
> 8192
> $ ./hello.ilp32 
> Hello World!
> $ ulimit -s unlimited
> $ ./hello.ilp32 
> Segmentation fault
> $ strace ./hello.ilp32 
> execve("./hello.ilp32", ["./hello.ilp32"], 0xfffff10548f0 /* 77 vars */) = -1 ENOMEM (Cannot allocate memory)
> +++ killed by SIGSEGV +++
> Segmentation fault (core dumped)
>
> Andreas.

Thanks Andreas, I will take a look. Do we have such test in LTP?
    
Yury

[LTP] [EXT] Re: [PATCH v9 00/24] ILP32 for ARM64

[Cyril Hrubis]

Hi!
> > There is a problem with the stack size accounting during execve when
> > there is no stack limit:
> >
> > $ ulimit -s
> > 8192
> > $ ./hello.ilp32 
> > Hello World!
> > $ ulimit -s unlimited
> > $ ./hello.ilp32 
> > Segmentation fault
> > $ strace ./hello.ilp32 
> > execve("./hello.ilp32", ["./hello.ilp32"], 0xfffff10548f0 /* 77 vars */) = -1 ENOMEM (Cannot allocate memory)
> > +++ killed by SIGSEGV +++
> > Segmentation fault (core dumped)
> >
> > Andreas.
> 
> Thanks Andreas, I will take a look. Do we have such test in LTP?

We do have a test that we can run a binary with very small stack size
i.e. 512kB but there does not seem to be anything that would catch this
specific problem.

Can you please open an issue and describe how to reproduce the problem
at our github tracker:

https://github.com/linux-test-project/ltp/issues

Then we can create testcase based on that reproducer later on.

-- 
Cyril Hrubis
chrubis@suse.cz

[LTP] [EXT] Re: [PATCH v9 00/24] ILP32 for ARM64

[Yury Norov]

On Tue, May 14, 2019 at 12:43:11PM +0200, Cyril Hrubis wrote:
> Hi!
> > > There is a problem with the stack size accounting during execve when
> > > there is no stack limit:
> > >
> > > $ ulimit -s
> > > 8192
> > > $ ./hello.ilp32 
> > > Hello World!
> > > $ ulimit -s unlimited
> > > $ ./hello.ilp32 
> > > Segmentation fault
> > > $ strace ./hello.ilp32 
> > > execve("./hello.ilp32", ["./hello.ilp32"], 0xfffff10548f0 /* 77 vars */) = -1 ENOMEM (Cannot allocate memory)
> > > +++ killed by SIGSEGV +++
> > > Segmentation fault (core dumped)
> > >
> > > Andreas.
> > 
> > Thanks Andreas, I will take a look. Do we have such test in LTP?

So the problem was in not converting new compat-sensitive code:

diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index 5bdf357169d8..c509f83fa506 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -63,7 +63,7 @@
 				TASK_SIZE_32 : TASK_SIZE_64)
 #define TASK_SIZE_OF(tsk)	(is_compat_thread(tsk) ? \
 				TASK_SIZE_32 : TASK_SIZE_64)
-#define DEFAULT_MAP_WINDOW	(test_thread_flag(TIF_32BIT) ? \
+#define DEFAULT_MAP_WINDOW	(is_compat_task() ? \
 				TASK_SIZE_32 : DEFAULT_MAP_WINDOW_64)
 #else
 #define TASK_SIZE		TASK_SIZE_64

The fix is incorporated in ilp32-5.1.1:
https://github.com/norov/linux/tree/ilp32-5.1.1

> We do have a test that we can run a binary with very small stack size
> i.e. 512kB but there does not seem to be anything that would catch this
> specific problem.
> 
> Can you please open an issue and describe how to reproduce the problem
> at our github tracker:
> 
> https://github.com/linux-test-project/ltp/issues
> 
> Then we can create testcase based on that reproducer later on.
> 
> -- 
> Cyril Hrubis
> chrubis@suse.cz

OK, I'll do.

Yury

[LTP] [EXT] Re: [PATCH v9 00/24] ILP32 for ARM64

[Yury Norov]

On Tue, May 14, 2019 at 12:43:11PM +0200, Cyril Hrubis wrote:
> Hi!
> > > There is a problem with the stack size accounting during execve when
> > > there is no stack limit:
> > >
> > > $ ulimit -s
> > > 8192
> > > $ ./hello.ilp32 
> > > Hello World!
> > > $ ulimit -s unlimited
> > > $ ./hello.ilp32 
> > > Segmentation fault
> > > $ strace ./hello.ilp32 
> > > execve("./hello.ilp32", ["./hello.ilp32"], 0xfffff10548f0 /* 77 vars */) = -1 ENOMEM (Cannot allocate memory)
> > > +++ killed by SIGSEGV +++
> > > Segmentation fault (core dumped)
> > >
> > > Andreas.
> > 
> > Thanks Andreas, I will take a look. Do we have such test in LTP?
> 
> We do have a test that we can run a binary with very small stack size
> i.e. 512kB but there does not seem to be anything that would catch this
> specific problem.
> 
> Can you please open an issue and describe how to reproduce the problem
> at our github tracker:
> 
> https://github.com/linux-test-project/ltp/issues
> 
> Then we can create testcase based on that reproducer later on.

This is it:
https://github.com/linux-test-project/ltp/issues/530

Yury