[GIT PULL] s390 fixes for 6.17-rc3

[GIT PULL] s390 fixes for 6.17-rc3

[Alexander Gordeev]

Hi Linus,

please pull s390 fixes for 6.17-rc3.

Thanks,
Alexander

The following changes since commit c17b750b3ad9f45f2b6f7e6f7f4679844244f0b9:

  Linux 6.17-rc2 (2025-08-17 15:22:10 -0700)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git tags/s390-6.17-3

for you to fetch changes up to 3868f910440c47cd5d158776be4ba4e2186beda7:

  s390/hypfs: Enable limited access during lockdown (2025-08-21 17:46:14 +0200)

----------------------------------------------------------------
s390 fixes for 6.17-rc3

- When kernel lockdown is active userspace tools that rely on read
  operations only are unnecessarily blocked. Fix that by avoiding
  ioctl registration during lockdown

- Invalid NULL pointer accesses succeed due to the lowcore is always
  mapped the identity mapping pinned to zero. To fix that never map
  the first two pages of physical memory with identity mapping

- Fix invalid SCCB present check in the SCLP interrupt handler

- Update defconfigs

----------------------------------------------------------------
Heiko Carstens (3):
      s390/configs: Update defconfigs
      s390/configs: Set HZ=1000
      s390/mm: Do not map lowcore with identity mapping

Peter Oberparleiter (3):
      s390/sclp: Fix SCCB present check
      s390/hypfs: Avoid unnecessary ioctl registration in debugfs
      s390/hypfs: Enable limited access during lockdown

 arch/s390/boot/vmem.c                |  3 +++
 arch/s390/configs/debug_defconfig    | 33 ++++++++++++++++-----------------
 arch/s390/configs/defconfig          | 34 +++++++++++++++-------------------
 arch/s390/configs/zfcpdump_defconfig |  3 ++-
 arch/s390/hypfs/hypfs_dbfs.c         | 19 ++++++++++++-------
 drivers/s390/char/sclp.c             | 11 +++++++++--
 6 files changed, 57 insertions(+), 46 deletions(-)

Re: [GIT PULL] s390 fixes for 6.17-rc3

[pr-tracker-bot]

The pull request you sent on Fri, 22 Aug 2025 14:36:08 +0200:

> git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git tags/s390-6.17-3

has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/cf6fc5eefc5bbbbff92a085039ff74cdbd065c29

Thank you!

-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/prtracker.html

Re: [GIT PULL] s390 fixes for 6.17-rc3

[Thomas Weißschuh]

Hi Alexander, Vasily and Heiko,

On 2025-08-22 14:36:08+0200, Alexander Gordeev wrote:
> please pull s390 fixes for 6.17-rc3.

(...)

>       s390/configs: Set HZ=1000

With this commit the nolibc testsuite for 32bit on QEMU 10.1.0 starts to
reliably crash. 64bit is fine. Actually I encountered the same problem
before this change, but it happened much less frequently.
Output below for a testrun that never got to print anything to stdout,
but the crashes can also happen later or sometimes not at all.

[    2.118473] Run /init as init process
[    2.142148] User process fault: interruption code 0006 ilc:0
[    2.142626] CPU: 0 UID: 0 PID: 1 Comm: init Not tainted 6.17.0-rc2-00002-gfcc43a7e294f #24 NONE
[    2.142739] Hardware name: QEMU 8561 QEMU (KVM/Linux)
[    2.142822] User PSW : 0705200080000000 00000000804087b2
[    2.142911]            R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:1 AS:0 CC:2 PM:0 RI:0 EA:1
[    2.142979] User GPRS: 0000000000000000 000000000040c060 ffffffffffffffff 0000000000000002
[    2.143022]            0000000000000800 00000000000007ff 0000000000000000 0000000000000000
[    2.143061]            0000000000000000 000003ff00000001 000000000040c000 000000007ff720ac
[    2.143106]            000000007ff720a4 0000000000409540 00000000804087b2 000000007ff71ec0
[    2.143406] User Code: Bad PSW.
[    2.143454] Last Breaking-Event-Address:
[    2.143483]  [<0000000000000001>]
[    2.144705] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000004
[    2.144875] CPU: 0 UID: 0 PID: 1 Comm: init Not tainted 6.17.0-rc2-00002-gfcc43a7e294f #24 NONE
[    2.144922] Hardware name: QEMU 8561 QEMU (KVM/Linux)
[    2.144989] Call Trace:
[    2.145292]  [<000003fffe657cf4>] vpanic+0x1dc/0x2f0
[    2.145535]  [<000003fffe657e4e>] panic+0x46/0x48
[    2.145586]  [<000003fffe65e4e2>] do_exit+0x3da/0x520
[    2.145634]  [<000003fffe65e820>] do_group_exit+0x40/0xb8
[    2.145683]  [<000003fffe66fc98>] copy_siginfo_to_user+0x0/0x60
[    2.145735]  [<000003fffe60614e>] arch_do_signal_or_restart+0x66/0x2b0
[    2.145787]  [<000003ffff42e2bc>] irqentry_exit_to_user_mode+0x174/0x1f8
[    2.145902]  [<000003ffff439d5c>] pgm_check_handler+0x114/0x160

You can run the testuite for yourself:
(run-tests.sh will download a cross toolchain)

$ cd tools/testing/selftests/nolibc
$ ./run-tests.sh -p s390
(Expected output, lower numbers mean failures)
s390:          228 test(s): 227 passed,   1 skipped,   0 failed => status: warning

The full test output will be in run.out.

This doesn't feel like an issue in nolibc to me.
Any ideas?


Thomas

Re: [GIT PULL] s390 fixes for 6.17-rc3

[Heiko Carstens]

On Thu, Oct 02, 2025 at 12:44:41AM +0200, Thomas Weißschuh wrote:
> Hi Alexander, Vasily and Heiko,
> 
> On 2025-08-22 14:36:08+0200, Alexander Gordeev wrote:
> > please pull s390 fixes for 6.17-rc3.
> 
> (...)
> 
> >       s390/configs: Set HZ=1000
> 
> With this commit the nolibc testsuite for 32bit on QEMU 10.1.0 starts to
> reliably crash. 64bit is fine. Actually I encountered the same problem
> before this change, but it happened much less frequently.
> Output below for a testrun that never got to print anything to stdout,
> but the crashes can also happen later or sometimes not at all.
> 
> [    2.118473] Run /init as init process
> [    2.142148] User process fault: interruption code 0006 ilc:0
> [    2.142626] CPU: 0 UID: 0 PID: 1 Comm: init Not tainted 6.17.0-rc2-00002-gfcc43a7e294f #24 NONE
> [    2.142739] Hardware name: QEMU 8561 QEMU (KVM/Linux)
> [    2.142822] User PSW : 0705200080000000 00000000804087b2
> [    2.142911]            R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:1 AS:0 CC:2 PM:0 RI:0 EA:1
> [    2.142979] User GPRS: 0000000000000000 000000000040c060 ffffffffffffffff 0000000000000002
> [    2.143022]            0000000000000800 00000000000007ff 0000000000000000 0000000000000000
> [    2.143061]            0000000000000000 000003ff00000001 000000000040c000 000000007ff720ac
> [    2.143106]            000000007ff720a4 0000000000409540 00000000804087b2 000000007ff71ec0
> [    2.143406] User Code: Bad PSW.
> [    2.143454] Last Breaking-Event-Address:
> [    2.143483]  [<0000000000000001>]
> [    2.144705] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000004
> [    2.144875] CPU: 0 UID: 0 PID: 1 Comm: init Not tainted 6.17.0-rc2-00002-gfcc43a7e294f #24 NONE
> [    2.144922] Hardware name: QEMU 8561 QEMU (KVM/Linux)
> [    2.144989] Call Trace:
> [    2.145292]  [<000003fffe657cf4>] vpanic+0x1dc/0x2f0
> [    2.145535]  [<000003fffe657e4e>] panic+0x46/0x48
> [    2.145586]  [<000003fffe65e4e2>] do_exit+0x3da/0x520
> [    2.145634]  [<000003fffe65e820>] do_group_exit+0x40/0xb8
> [    2.145683]  [<000003fffe66fc98>] copy_siginfo_to_user+0x0/0x60
> [    2.145735]  [<000003fffe60614e>] arch_do_signal_or_restart+0x66/0x2b0
> [    2.145787]  [<000003ffff42e2bc>] irqentry_exit_to_user_mode+0x174/0x1f8
> [    2.145902]  [<000003ffff439d5c>] pgm_check_handler+0x114/0x160
> 
> You can run the testuite for yourself:
> (run-tests.sh will download a cross toolchain)
> 
> $ cd tools/testing/selftests/nolibc
> $ ./run-tests.sh -p s390
> (Expected output, lower numbers mean failures)
> s390:          228 test(s): 227 passed,   1 skipped,   0 failed => status: warning
> 
> The full test output will be in run.out.
> 
> This doesn't feel like an issue in nolibc to me.
> Any ideas?

Hm, this looks like a qemu bug to me.

Ilya, could you have a look at this please?

The above report is a specification exception with an instruction length
code of zero, while the PSW points to a 31 bit user space address. As far
as I understand the architecture this is only possible for an early PSW
specification exception (aka invalid PSW); however the PSW looks good to
me.

So something seems to be odd here.

Re: [GIT PULL] s390 fixes for 6.17-rc3

[Heiko Carstens]

On Thu, Oct 02, 2025 at 01:05:26PM +0200, Heiko Carstens wrote:
> On Thu, Oct 02, 2025 at 12:44:41AM +0200, Thomas Weißschuh wrote:
> > Hi Alexander, Vasily and Heiko,
> > [    2.118473] Run /init as init process
> > [    2.142148] User process fault: interruption code 0006 ilc:0
> > [    2.142626] CPU: 0 UID: 0 PID: 1 Comm: init Not tainted 6.17.0-rc2-00002-gfcc43a7e294f #24 NONE
> > [    2.142739] Hardware name: QEMU 8561 QEMU (KVM/Linux)
> > [    2.142822] User PSW : 0705200080000000 00000000804087b2
                                                       ^
> > [    2.142911]            R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:1 AS:0 CC:2 PM:0 RI:0 EA:1
> > [    2.142979] User GPRS: 0000000000000000 000000000040c060 ffffffffffffffff 0000000000000002
> > [    2.143022]            0000000000000800 00000000000007ff 0000000000000000 0000000000000000
> > [    2.143061]            0000000000000000 000003ff00000001 000000000040c000 000000007ff720ac
> > [    2.143106]            000000007ff720a4 0000000000409540 00000000804087b2 000000007ff71ec0
> > [    2.143406] User Code: Bad PSW.
> > [    2.144705] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000004

...

> Hm, this looks like a qemu bug to me.
> 
> Ilya, could you have a look at this please?
> 
> The above report is a specification exception with an instruction length
> code of zero, while the PSW points to a 31 bit user space address. As far
> as I understand the architecture this is only possible for an early PSW
> specification exception (aka invalid PSW); however the PSW looks good to
> me.

I was wrong, the above bit should be zero otherwise it is indeed an early
PSW specification exception. I'll figure out where this comes from, but
might take a few days due to public holiday.