Re: io_uring failure on parisc (32-bit userspace and 64-bit kernel)

Jens Axboe
2023-02-12T13:16:38Z

On 2/12/23 2:47?AM, Helge Deller wrote:
> Hi all,
>
> We see io-uring failures on the parisc architecture with this testcase:
> https://github.com/axboe/liburing/blob/master/examples/io_uring-test.c
>
> parisc is always big-endian 32-bit userspace, with either 32- or 64-bit kernel.
>
> On a 64-bit kernel (6.1.11):
> deller@parisc:~$ ./io_uring-test test.file
> ret=0, wanted 4096
> Submitted=4, completed=1, bytes=0
> -> failure
>
> strace shows:
> io_uring_setup(4, {flags=0, sq_thread_cpu=0, sq_thread_idle=0, sq_entries=4, cq_entries=8, features=IORING_FEAT_SINGLE_MMAP|IORING_FEAT_NODROP|IORING_FEAT_SUBMIT_STABLE|IORING_FEAT_RW_CUR_POS|IORING_FEAT_CUR_PERSONALITY|IORING_FEAT_FAST_POLL|IORING_FEAT_POLL_32BITS|0x1f80, sq_off={head=0, tail=16, ring_mask=64, ring_entries=72, flags=84, dropped=80, array=224}, cq_off={head=32, tail=48, ring_mask=68, ring_entries=76, overflow=92, cqes=96, flags=0x58 /* IORING_CQ_??? */}}) = 3
> mmap2(NULL, 240, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_POPULATE, 3, 0) = 0xf7522000
> mmap2(NULL, 256, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_POPULATE, 3, 0x10000000) = 0xf6922000
> openat(AT_FDCWD, "libell0-dbgsym_0.56-2_hppa.deb", O_RDONLY|O_DIRECT) = 4
> statx(4, "", AT_STATX_SYNC_AS_STAT|AT_NO_AUTOMOUNT|AT_EMPTY_PATH, STATX_BASIC_STATS, {stx_mask=STATX_BASIC_STATS|STATX_MNT_ID, stx_attributes=0, stx_mode=S_IFREG|0644, stx_size=689308, ...}) = 0
> getrandom("\x5c\xcf\x38\x2d", 4, GRND_NONBLOCK) = 4
> brk(NULL) = 0x4ae000
> brk(0x4cf000) = 0x4cf000
> io_uring_enter(3, 4, 0, 0, NULL, 8) = 0
>
>
> Running the same testcase on a 32-bit kernel (6.1.11) works:
> root@debian:~# ./io_uring-test test.file
> Submitted=4, completed=4, bytes=16384
> -> ok.
>
> strace:
> io_uring_setup(4, {flags=0, sq_thread_cpu=0, sq_thread_idle=0, sq_entries=4, cq_entries=8, features=IORING_FEAT_SINGLE_MMAP|IORING_FEAT_NODROP|IORING_FEAT_SUBMIT_STABLE|IORING_FEAT_RW_CUR_POS|IORING_FEAT_CUR_PERSONALITY|IORING_FEAT_FAST_POLL|IORING_FEAT_POLL_32BITS|0x1f80, sq_off={head=0, tail=16, ring_mask=64, ring_entries=72, flags=84, dropped=80, array=224}, cq_off={head=32, tail=48, ring_mask=68, ring_entries=76, overflow=92, cqes=96, flags=0x58 /* IORING_CQ_??? */}}) = 3
> mmap2(NULL, 240, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_POPULATE, 3, 0) = 0xf6d4c000
> mmap2(NULL, 256, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_POPULATE, 3, 0x10000000) = 0xf694c000
> openat(AT_FDCWD, "trace.dat", O_RDONLY|O_DIRECT) = 4
> statx(4, "", AT_STATX_SYNC_AS_STAT|AT_NO_AUTOMOUNT|AT_EMPTY_PATH, STATX_BASIC_STATS, {stx_mask=STATX_BASIC_STATS|STATX_MNT_ID, stx_attributes=0, stx_mode=S_IFREG|0644, stx_size=1855488, ...}) = 0
> getrandom("\xb2\x3f\x0c\x65", 4, GRND_NONBLOCK) = 4
> brk(NULL) = 0x15000
> brk(0x36000) = 0x36000
> io_uring_enter(3, 4, 0, 0, NULL, 8) = 4
>
> I'm happy to test any patch if someone has an idea....

No idea what this could be, to be honest. I tried your qemu vm image,
and it does boot, but it's missing keys to be able to update apt and
install packages... After fiddling with this for 30 min I gave up, any
chance you can update the sid image? Given how slow this thing is
running, it'd take me all day to do a fresh install and I have to admit
I'm not THAT motivated about parisc to do that :)

--
Jens Axboe