On Mon, Oct 10, 2022 at 01:25:25PM -0600, Jason A. Donenfeld wrote:
> Hi Michael,
>
> On Sun, Oct 09, 2022 at 10:01:39PM +1100, Michael Ellerman wrote:
> > powerpc updates for 6.1
> >
> > - Remove our now never-true definitions for pgd_huge() and p4d_leaf().
> >
> > - Add pte_needs_flush() and huge_pmd_needs_flush() for 64-bit.
> >
> > - Add support for syscall wrappers.
> >
> > - Add support for KFENCE on 64-bit.
> >
> > - Update 64-bit HV KVM to use the new guest state entry/exit accounting
> > API.
> >
> > - Support execute-only memory when using the Radix MMU (P9 or later).
> >
> > - Implement CONFIG_PARAVIRT_TIME_ACCOUNTING for pseries guests.
> >
> > - Updates to our linker script to move more data into read-only sections.
> >
> > - Allow the VDSO to be randomised on 32-bit.
> >
> > - Many other small features and fixes.
>
> FYI, something in here broke the wireguard test suite, which runs the
> iperf3 networking utility. The full log is here [1], but the relevant part
> is:
>
> [+] NS1: iperf3 -Z -t 3 -c 192.168.241.2
> Connecting to host 192.168.241.2, port 5201
> iperf3: error - failed to read /dev/urandom: Bad address
>
> I'll see if I can narrow it down a bit more and bisect. But just FYI, in
> case you have an intuition.
Huh. From iov_iter.c:
static int copyout(void __user *to, const void *from, size_t n)
{
size_t before = n;
if (should_fail_usercopy())
return n;
if (access_ok(to, n)) {
instrument_copy_to_user(to, from, n);
n = raw_copy_to_user(to, from, n);
if (n == before)
pr_err("SARU n still %zu pointer is %lx\n", n,
(unsigned long)to);
}
return n;
}
I added the pr_err() there to catch the failure:
[ 3.443506] SARU n still 64 pointer is b78db000
Also I managed to extract the failing portion of iperf3 into something
smaller:
int temp;
char *x;
ssize_t l;
FILE *f;
char template[] = "/blah-XXXXXX";
temp = mkstemp(template);
if (temp < 0)
panic("mkstemp");
if (unlink(template) < 0)
panic("unlink");
if (ftruncate(temp, 0x20000) < 0)
panic("ftruncate");
x = mmap(NULL, 0x20000, PROT_READ|PROT_WRITE, MAP_PRIVATE, temp, 0);
if (x == MAP_FAILED)
panic("mmap");
f = fopen("/dev/urandom", "rb");
if (!f)
panic("fopen");
setbuf(f, NULL);
if (fread(x, 1, 0x20000, f) != 0x20000)
panic("fread");
Jason
