On Fri, Feb 27, 2026 at 3:05 AM Christophe Leroy (CS GROUP) <[email protected]> wrote: > > > > 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 >
Hi， Christophe confirmed that after applying the patch https://lore.kernel.org/all/[email protected]/, this issue has not been hit again, the fix works. Thanks, Changhui
