kernel/linux.git/arch/um/os-Linux, branch v6.18.21

um: Preserve errno within signal handler

2026-03-04T12:20:28+00:00

[ Upstream commit f68b2d5a907b53eed99cf2efcaaae116df73c298 ] We rely on errno to determine whether a syscall has failed, so we need to ensure that accessing errno is async-signal-safe. Currently, we preserve the errno in sig_handler_common(), but it doesn't cover every possible case. Let's do it in hard_handler() instead, which is the signal handler we actually register. Signed-off-by: Tiwei Bie Link: https://patch.msgid.link/20260106001228.1531146-2-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin

Merge tag 'uml-for-linux-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux

2025-10-06T19:10:55+00:00

Pull uml updates from Johannes Berg: - minor preparations for SMP support - SPARSE_IRQ support for kunit - help output cleanups * tag 'uml-for-linux-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux: um: Remove unused ipi_pipe field from cpuinfo_um um: Remove unused cpu_data and current_cpu_data macros um: Stop tracking virtual CPUs via mm_cpumask() um: Centralize stub size calculations um: Remove outdated comment about STUB_DATA_PAGES um: Remove unused offset and child_err fields from stub_data um: Indent time-travel help messages um: Fix help message for ssl-non-raw um: vector: Fix indentation for help message um: Add missing trailing newline to help messages um: virtio-pci: implement .shutdown() um: Support SPARSE_IRQ

um: Fix FD copy size in os_rcv_fd_msg()

2025-09-10T12:24:19+00:00

When copying FDs, the copy size should not include the control message header (cmsghdr). Fix it. Fixes: 5cde6096a4dd ("um: generalize os_rcv_fd") Signed-off-by: Tiwei Bie Signed-off-by: Johannes Berg

um: Don't mark stack executable

2025-09-10T12:24:13+00:00

On one of my machines UML failed to start after enabling SELinux. UML failed to start because SELinux's execmod rule denies executable pages on a modified file mapping. Historically UML marks it's stack rwx. AFAICT, these days this is no longer needed, so let's remove PROT_EXEC. Signed-off-by: Richard Weinberger Signed-off-by: Johannes Berg

um: Add missing trailing newline to help messages

2025-09-10T12:23:37+00:00

Some help messages are missing a trailing newline. They should end with two newlines, but only one is present. Add the missing newline to make the --help output more readable. Signed-off-by: Tiwei Bie Signed-off-by: Johannes Berg

um: Stop tracking stub's PID via userspace_pid[]

2025-07-13T17:42:49+00:00

The PID of the stub process can be obtained from current_mm_id(). There is no need to track it via userspace_pid[]. Stop doing that to simplify the code. Signed-off-by: Tiwei Bie Link: https://patch.msgid.link/20250711065021.2535362-4-tiwei.bie@linux.dev Signed-off-by: Johannes Berg

um: Remove the pid parameter of handle_trap()

2025-07-13T17:42:49+00:00

It's no longer used. Remove it. Signed-off-by: Tiwei Bie Link: https://patch.msgid.link/20250711065021.2535362-3-tiwei.bie@linux.dev Signed-off-by: Johannes Berg

um: Use err consistently in userspace()

2025-07-13T17:42:49+00:00

Avoid declaring a new variable 'ret' inside the 'if (using_seccomp)' block, as the existing 'err' variable declared at the top of the function already serves the same purpose. Signed-off-by: Tiwei Bie Link: https://patch.msgid.link/20250711065021.2535362-2-tiwei.bie@linux.dev Signed-off-by: Johannes Berg

um: Make unscheduled_userspace_iterations static

2025-07-11T06:49:17+00:00

It's only used within process.c. Make it static. Signed-off-by: Tiwei Bie Link: https://patch.msgid.link/20250708090403.1067440-2-tiwei.bie@linux.dev Signed-off-by: Johannes Berg

um: fix SECCOMP 32bit xstate register restore

2025-06-04T09:40:36+00:00

There was a typo that caused the extended FP state to be copied into the wrong location on 32 bit. On 32 bit we only store the xstate internally as that already contains everything. However, for compatibility, the mcontext on 32 bit first contains the legacy FP state and then the xstate. The code copied the xstate on top of the legacy FP state instead of using the correct offset. This offset was already calculated in the xstate_* variables, so simply switch to those to fix the problem. With this SECCOMP mode works on 32 bit, so lift the restriction. Fixes: b1e1bd2e6943 ("um: Add helper functions to get/set state for SECCOMP") Signed-off-by: Benjamin Berg Link: https://patch.msgid.link/20250604081705.934112-1-benjamin@sipsolutions.net Signed-off-by: Johannes Berg