6.13+ uml crash

[Maciej Żenczykowski]

On Tue, Apr 7, 2026 at 2:56 PM Berg, Johannes <johannes.berg at intel.com> wrote:
> Hi,
>
> Haven't looked at this yet - but really better if you CC the UML list.
>
> johannes
>
> > -----Original Message-----
> > From: Maciej Żenczykowski <maze at google.com>
> > Sent: Saturday, April 4, 2026 5:25 AM
> > To: Berg, Benjamin <benjamin.berg at intel.com>; Berg, Johannes
> > <johannes.berg at intel.com>; Tiwei Bie <tiwei.btw at antgroup.com>
> > Subject: Re: 6.13+ uml crash
> >
> > On Fri, Apr 3, 2026 at 12:34 PM Maciej Żenczykowski <maze at google.com>
> > wrote:
> > >
> > > Host is:
> > >
> > > 6.18.14-1rodete1-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.18.14-
> > 1rodete1
> > > (2026-03-06) x86_64 GNU/Linux
> > >
> > > /proc/cmdline
> > > ima_hash=sha256 kfence.sample_interval=100 intel_iommu=sm_off
> > > pci=noats printk.devkmsg=on slab_nomerge
> > > lsm=landlock,lockdown,yama,loadpin,safesetid,integrity,apparmor,selinu
> > > x,smack,tomoyo,bpf
> > > apparmor=1 panic=30 glinux-boot-image=default-20260324.03.00
> > > earlycon=uart8250,io,0x3f8 console=ttyS0,115200n8 console=hvc0
> > > console=tty0 splash plymouth.ignore-serial-consoles i915.enable_psr=0
> > >
> > > No SELinux, but I think there is likely some corporate AppArmor policy...
> > >
> > > I seem to hit this problem while trying to use UML on latest
> > > 6.13/6.14/6.15/6.16/6.17/6.18/6.19
> > > 6.12 guests are the last ones that work.
> > >
> > > I noticed 6.13 had many UML changes...
> > >
> > > This is while trying to run the android net tests.
> > >
> > > https://android.googlesource.com/kernel/tests/+log/refs/heads/mirror-g
> > > oog-main-kernel /aosp-tests/net/test/run_net_test.sh --builder
> > > all_tests.sh
> > >
> > > ...
> > > VFS: Mounted root (ext3 filesystem) readonly on device 98:0.
> > > devtmpfs: mounted
> > > This architecture does not have kernel memory protection.
> > > Run /sbin/net_test.sh as init process
> > > Registers -
> > >         0       0x60025a90
> > >         1       0x2e2ea5
> > >         2       0x600423e4
> > >         3       0x2e2ea8
> > >         4       0x7fffffffbe30
> > >         5       0x0
> > >         6       0x206
> > >         7       0x0
> > >         8       0x7fffffffbe30
> > >         9       0xffffffff
> > >         10      0x0
> > >         11      0x7ffff7c40c87
> > >         12      0x0
> > >         13      0x13
> > >         14      0x2e2ea8
> > >         15      0x3e
> > >         16      0x7fffffffc000
> > >         17      0x33
> > >         18      0x206
> > >         19      0x7fffffffeff8
> > >         20      0x2b
> > >         21      0x7ffff7f9d740
> > >         22      0x0
> > >         23      0x0
> > >         24      0x0
> > >         25      0x0
> > >         26      0x0
> > > Kernel panic - not syncing: do_syscall_stub : PTRACE_SETREGS failed,
> > > errno = 3  [ESRCH]
> > > CPU: 0 UID: 0 PID: 1 Comm: net_test.sh Not tainted
> > > 6.13.12-g2abfa5d47651 #3
> > > Stack:
> > >  600277e4 60629dd1 80803d80 00000000
> > >  00000001 60629dd1 6061c0a9 600277e4
> > >  80803db0 6002efd2 60c70000 609171c0
> > > Call Trace:
> > >  [<600277e4>] ? _printk+0x0/0x57
> > >  [<600322ec>] show_stack+0x10b/0x11a
> > >  [<600277e4>] ? _printk+0x0/0x57
> > >  [<600277e4>] ? _printk+0x0/0x57
> > >  [<6002efd2>] dump_stack_lvl+0x5e/0x79  [<6002f007>]
> > > dump_stack+0x1a/0x1c  [<60026838>] panic+0x156/0x377  [<600277e4>] ?
> > > _printk+0x0/0x57  [<600266e2>] ? panic+0x0/0x377  [<600277e4>] ?
> > > _printk+0x0/0x57  [<6004555b>] do_syscall_stub+0xa6/0x132
> > > [<60031608>] ? interrupt_end+0x0/0xae  [<6004560b>]
> > > syscall_stub_flush+0x24/0x2e  [<60045daf>] userspace+0x81/0x469
> > > [<60031608>] ? interrupt_end+0x0/0xae  [<601761ba>] ?
> > > copy_strings_kernel+0x0/0x9e  [<60031509>]
> > > new_thread_handler+0x5a/0x5e
> > > /aosp-tests/net/test/run_net_test.sh: line 498: 3026597 Aborted
> > >             (core dumped) $KERNEL_BINARY umid=net_test mem=512M
> > > $blockdevice=$ROOTFS $netconfig $consolemode ssl3=null,fd:3 $cmdline
> > > 1>&2 3> "${SSL3}"
> > > Warning: UML exited with 134 instead of zero.
> >
> > It appears this broke at:
> >
> > commit 32e8eaf263d9be014ba1970444f745682fa9c6c0
> > Author: Benjamin Berg <benjamin.berg at intel.com>
> >     um: use execveat to create userspace MMs
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--
Maciej Żenczykowski, Kernel Networking Developer @ Google