Le 26/02/2026 à 17:59, Caleb Sander Mateos a écrit :
On Thu, Feb 26, 2026 at 4:44 AM Ming Lei <[email protected]> wrote:
On Thu, Feb 26, 2026 at 6:48 PM Ming Lei <[email protected]> wrote:
Hi Changhui,
Thanks for the report!
Loop Caleb Sander Mateos in.
Thanks,
On Thu, Feb 26, 2026 at 6:37 PM Changhui Zhong <[email protected]> wrote:
Hello,
on the ppc64le arch, I hit the issue below with ublksrv on the latest
linux-block/for-next, please help check it, and let me know if you
need any info/test for it. Thanks.
INFO: HEAD of cloned kernel
commit 37a43fd770f3dcac8f72f3ea909b3e893e2385c9
Merge: 13cd9b41227a c1dfbd7e71b0
Author: Jens Axboe <[email protected]>
Date: Wed Feb 25 08:37:06 2026 -0700
Merge branch 'for-7.1/block' into for-next
* for-7.1/block:
ublk: report BLK_SPLIT_INTERVAL_CAPABLE
reproducer:
compile and install
https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fublk-org%2Fublksrv.git&data=05%7C02%7Cchristophe.leroy2%40cs-soprasteria.com%7Cf0b0066758be476be95508de75587a73%7C8b87af7d86474dc78df45f69a2011bb5%7C0%7C0%7C639077220067774377%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=ki4yUMx%2FBTANcpfzEoVMdBKsuflIbzhHO2Wqpxtvj5g%3D&reserved=0
#echo 0 > /proc/sys/kernel/io_uring_disabled
#modprobe ublk_drv
#cd ublksrv
#make test T=null
#make test T=loop
dmesg log：
Feb 26 00:24:30 ibm-p9z-27-lp26 journal: running null/002
Feb 26 00:24:30 ibm-p9z-27-lp26 ublksrvd-0[57921]: start ublksrv io
daemon ublksrvd-0
Feb 26 00:24:30 ibm-p9z-27-lp26 ublksrvd-0[57921]: tid 57923: ublk dev
0 queue 0 started
Feb 26 00:24:30 ibm-p9z-27-lp26 ublksrvd-0[57921]: tid 57924: ublk dev
0 queue 1 started
Feb 26 00:24:36 ibm-p9z-27-lp26 NetworkManager[818]: <warn>
[1772083476.4882] platform-linux: do-add-ip6-address[2:
fe80::8448:a3ff:fe51:f102]: failure 13 (Permission denied - ipv6: IPv6
is disabled on this device)
Feb 26 00:24:36 ibm-p9z-27-lp26 NetworkManager[818]: <warn>
[1772083476.4885] platform-linux: do-add-ip6-address[2:
2620:52:9:160c:8448:a3ff:fe51:f102]: failure 13 (Permission denied -
ipv6: IPv6 is disabled on this device)
Feb 26 00:24:36 ibm-p9z-27-lp26 NetworkManager[818]: <warn>
[1772083476.4938] l3cfg[0f1985ec14299e62,ifindex=2]: unable to
configure IPv6 route: type unicast fe80::/64 dev 2 metric 1024 mss 0
rt-src ipv6ll
Feb 26 00:24:38 ibm-p9z-27-lp26 NetworkManager[818]: <warn>
[1772083478.4938] ipv6ll[95ab7f3fdbfe643d,ifindex=2]: changed: no IPv6
link local address to retry after Duplicate Address Detection failures
(back off)
Feb 26 00:24:38 ibm-p9z-27-lp26 NetworkManager[818]: <warn>
[1772083478.4943] platform-linux: do-add-ip6-address[2:
2620:52:9:160c:8448:a3ff:fe51:f102]: failure 13 (Permission denied -
ipv6: IPv6 is disabled on this device)
Feb 26 00:24:48 ibm-p9z-27-lp26 NetworkManager[818]: <warn>
[1772083488.5034] platform-linux: do-add-ip6-address[2:
fe80::8448:a3ff:fe51:f102]: failure 13 (Permission denied - ipv6: IPv6
is disabled on this device)
Feb 26 00:24:48 ibm-p9z-27-lp26 NetworkManager[818]: <warn>
[1772083488.5037] platform-linux: do-add-ip6-address[2:
2620:52:9:160c:8448:a3ff:fe51:f102]: failure 13 (Permission denied -
ipv6: IPv6 is disabled on this device)
Feb 26 00:24:48 ibm-p9z-27-lp26 NetworkManager[818]: <warn>
[1772083488.5041] l3cfg[0f1985ec14299e62,ifindex=2]: unable to
configure IPv6 route: type unicast fe80::/64 dev 2 metric 1024 mss 0
rt-src ipv6ll
Feb 26 00:24:50 ibm-p9z-27-lp26 NetworkManager[818]: <warn>
[1772083490.5034] ipv6ll[95ab7f3fdbfe643d,ifindex=2]: changed: no IPv6
link local address to retry after Duplicate Address Detection failures
(back off)
Feb 26 00:24:50 ibm-p9z-27-lp26 NetworkManager[818]: <warn>
[1772083490.5039] platform-linux: do-add-ip6-address[2:
2620:52:9:160c:8448:a3ff:fe51:f102]: failure 13 (Permission denied -
ipv6: IPv6 is disabled on this device)
Feb 26 00:24:58 ibm-p9z-27-lp26 kernel: Kernel attempted to read user
page (7fff81210000) - exploit attempt? (uid: 0)
Feb 26 00:24:58 ibm-p9z-27-lp26 kernel: ------------[ cut here ]------------
Feb 26 00:24:58 ibm-p9z-27-lp26 kernel: Bug: Read fault blocked by KUAP!
Feb 26 00:24:58 ibm-p9z-27-lp26 kernel: WARNING:
arch/powerpc/mm/fault.c:231 at bad_kernel_fault.isra.0+0xc8/0x2c0,
CPU#5: lt-ublk.null/57924
oops, it shouldn't be related with `ublk: report BLK_SPLIT_INTERVAL_CAPABLE`,
Perhaps one issue lies in the ppcle64 architecture code.
Agreed, the "Kernel attempted to read user page" error seems
incorrect. The call trace shows this is in copy_from_iter(), so
reading a user page is expected. I too would be suspicious of the
powerpc copy_from_iter() implementation.
Looks similar to:
https://lore.kernel.org/all/[email protected]/
That fix was rejected, more acceptable fix here:
https://lore.kernel.org/all/[email protected]/
Let us know if it fixes the issue for you.
Christophe
