[CRIU] zdtm/static/fd failure on aarch64

[Adrian Reber]

On Tue, Jun 12, 2018 at 05:33:56PM +0100, Dmitry Safonov wrote:
> 2018-06-12 17:23 GMT+01:00 Adrian Reber <adrian at lisas.de>:
> > On Tue, Jun 12, 2018 at 04:13:05PM +0100, Dmitry Safonov wrote:
> >> 2018-06-12 7:48 GMT+01:00 Adrian Reber <adrian at lisas.de>:
> >> > Output is always like this:
> >> >
> >> > 02:20:50.173: 11691: ERR: ../lib/lock.h:149: futex *0xffff86100000 = 0, c = 2249195520 (errno = 11 (Resource temporarily unavailable))
> >> >
> >> > 11691 mmap(NULL, 65536, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_ANONYMOUS, -1, 0) = 0xffff86100000
> >> > 11691 futex(0xffff86100000, FUTEX_WAIT, 2249195521, NULL) = -1 EAGAIN (Resource temporarily unavailable)
> >> > 11691 brk(NULL)                         = 0x149f0000
> >> > 11691 brk(0x14a20000)                   = 0x14a20000
> >> > 11691 brk(NULL)                         = 0x14a20000
> >> > 11691 openat(AT_FDCWD, "/etc/localtime", O_RDONLY|O_CLOEXEC) = 4
> >> > 11691 fstat(4, {st_mode=S_IFREG|0644, st_size=3519, ...}) = 0
> >> > 11691 fstat(4, {st_mode=S_IFREG|0644, st_size=3519, ...}) = 0
> >> > 11691 mmap(NULL, 65536, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xffff860f0000
> >> > 11691 read(4, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\4\0\0\0\4\0\0\0\0"..., 8192) = 3519
> >> > 11691 lseek(4, -2252, SEEK_CUR)         = 1267
> >> > 11691 read(4, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\5\0\0\0\5\0\0\0\0"..., 8192) = 2252
> >> > 11691 close(4)                          = 0
> >> > 11691 munmap(0xffff860f0000, 65536)     = 0
> >> > 11691 write(2, "02:20:50.173: 11691: ERR: ../lib"..., 135) = 135
> >> > 11691 futex(0xffff86100000, FUTEX_WAIT, 2249195521, NULL) = -1 EAGAIN (Resource temporarily unavailable)
> >> > 11691 newfstatat(AT_FDCWD, "/etc/localtime", {st_mode=S_IFREG|0644, st_size=3519, ...}, 0) = 0
> >> > 11691 write(2, "02:20:50.175: 11691: ERR: ../lib"..., 135) = 135
> >> >
> >> > How I understand it is that atomic_inc() should return the new value but the returned value
> >> > is completely different from what atomic_get() returns, right?
> >>
> >> Well, atomic_inc() should return the old value, AFAICS from code.
> >> atomic_inc_return() should return the new value.
> >>
> >> I think it's not due cast we've some garbage value, it looks as if
> >> we're doing 16-bit operations on 32-bit values.. But we aren't as far
> >> as I can catch from arm64 asm.
> >>
> >> Could you try with this to see, if atomic ops work?
> >
> > 11:47:58.974: 15442: ERR: ../lib/lock.h:152: futex *0xffffb1d50000 = 0, c = 2983526400, +0 = 2983526400, -0 = 2983526400 (errno = 11 (Resource temporarily unavailable))
> >
> > Looks wrong. But looking at the lower bits of 0xffffb1d50000 I see that
> > 0xb1d50000 is the same as 2983526400. So instead of the value we get the
> > lower bits of the address.
> >
> >> Probably also worth to try to zero-init `tmp'/`result' inside ops to check
> >> if the result is garbage from the stack in ops function.
> >
> > I already tried that, but it did not change anything.
> 
> Probably, could you try with this?
> (haven't compile-tested on arm64)

I thought I tried exactly that, because that is the required fix. This
also fixes zdtm/transition/maps007. All your other changes are not
applied right now.

Now only cow01 is failing. Thanks for remote debugging.

> diff --git a/test/zdtm/lib/arch/aarch64/include/asm/atomic.h b/test/zdtm/lib/arch/aarch64/include/asm/atomic.h
> index ccf08e700478..ddf4ad9f60e8 100644
> --- a/test/zdtm/lib/arch/aarch64/include/asm/atomic.h
> +++ b/test/zdtm/lib/arch/aarch64/include/asm/atomic.h
> @@ -33,7 +33,7 @@ static inline int atomic_add_return(int i, atomic_t *v)
>  "	add	%w0, %w0, %w3\n"
>  "	stlxr	%w1, %w0, %2\n"
>  "	cbnz	%w1, 1b"
> -	: "=&r" (result), "=&r" (tmp), "+Q" (v)
> +	: "=&r" (result), "=&r" (tmp), "+Q" (*v)
>  	: "Ir" (i)
>  	: "cc", "memory");
>  
> @@ -51,7 +51,7 @@ static inline int atomic_sub_return(int i, atomic_t *v)
>  "	sub	%w0, %w0, %w3\n"
>  "	stlxr	%w1, %w0, %2\n"
>  "	cbnz	%w1, 1b"
> -	: "=&r" (result), "=&r" (tmp), "+Q" (v)
> +	: "=&r" (result), "=&r" (tmp), "+Q" (*v)
>  	: "Ir" (i)
>  	: "cc", "memory");
>  


		Adrian