linux.git/arch/um/os-Linux/process.c, branch for-next Linux kernel source tree um: Add os_set_pdeathsig helper function 2024-10-25T09:34:54+00:00 Tiwei Bie tiwei.btw@antgroup.com 2024-10-24T14:28:25+00:00 4e5adbe447db382cc76e05613581f96aef4f91d2 This helper can be used to set the parent-death signal of the calling process to SIGKILL to ensure that the process will be killed if the UML kernel dies unexpectedly without proper cleanup. This helper will be used in the follow-up patches. Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com> Link: https://patch.msgid.link/20241024142828.2612828-2-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg <johannes.berg@intel.com> 
This helper can be used to set the parent-death signal of the calling
process to SIGKILL to ensure that the process will be killed if the
UML kernel dies unexpectedly without proper cleanup. This helper will
be used in the follow-up patches.

Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241024142828.2612828-2-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
um: Remove unused os_getpgrp function 2024-10-10T10:02:04+00:00 Benjamin Berg benjamin.berg@intel.com 2024-09-13T13:44:41+00:00 71fae9dfa7e3a987886c8baf235d5a0b96e5dc15 The function is not used anywhere. Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20240913134442.967599-5-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com> 
The function is not used anywhere.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20240913134442.967599-5-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
um: Remove unused os_stop_process 2024-10-10T10:02:04+00:00 Benjamin Berg benjamin.berg@intel.com 2024-09-13T13:44:40+00:00 377c23c5588d1f3d572b21d429dd95157bd8b5a9 The function is not used anywhere. Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20240913134442.967599-4-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com> 
The function is not used anywhere.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20240913134442.967599-4-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
um: Remove unused os_process_parent 2024-10-10T10:02:04+00:00 Benjamin Berg benjamin.berg@intel.com 2024-09-13T13:44:39+00:00 47e174969cbf9244add188635a9590ff717d796e The function is not used anywhere. Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20240913134442.967599-3-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com> 
The function is not used anywhere.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20240913134442.967599-3-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
um: Remove unused os_process_pc 2024-10-10T10:02:04+00:00 Benjamin Berg benjamin.berg@intel.com 2024-09-13T13:44:38+00:00 7852ee068afe97eec3e955de3c4197aeb4793c52 The function is not used anywhere in the codebase. Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20240913134442.967599-2-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com> 
The function is not used anywhere in the codebase.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20240913134442.967599-2-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
um: Add SPDX headers for files in arch/um/os-Linux 2019-09-15T19:37:17+00:00 Alex Dewar alex.dewar@gmx.co.uk 2019-08-25T09:49:18+00:00 97870c34b453251cda9c2341f8534b78003a74dc Convert files to use SPDX header. All files are licensed under the GPLv2. Signed-off-by: Alex Dewar <alex.dewar@gmx.co.uk> Signed-off-by: Richard Weinberger <richard@nod.at> 
Convert files to use SPDX header. All files are licensed under the GPLv2.

Signed-off-by: Alex Dewar <alex.dewar@gmx.co.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
um: Switch clocksource to hrtimers 2015-11-06T21:54:49+00:00 Anton Ivanov aivanov@brocade.com 2015-11-02T16:16:37+00:00 2eb5f31bc4ea24bb293e82934cfa1cce9573304b UML is using an obsolete itimer call for all timers and "polls" for kernel space timer firing in its userspace portion resulting in a long list of bugs and incorrect behaviour(s). It also uses ITIMER_VIRTUAL for its timer which results in the timer being dependent on it running and the cpu load. This patch fixes this by moving to posix high resolution timers firing off CLOCK_MONOTONIC and relaying the timer correctly to the UML userspace. Fixes: - crashes when hosts suspends/resumes - broken userspace timers - effecive ~40Hz instead of what they should be. Note - this modifies skas behavior by no longer setting an itimer per clone(). Timer events are relayed instead. - kernel network packet scheduling disciplines - tcp behaviour especially under load - various timer related corner cases Finally, overall responsiveness of userspace is better. Signed-off-by: Thomas Meyer <thomas@m3y3r.de> Signed-off-by: Anton Ivanov <aivanov@brocade.com> [rw: massaged commit message] Signed-off-by: Richard Weinberger <richard@nod.at> 
UML is using an obsolete itimer call for
all timers and "polls" for kernel space timer firing
in its userspace portion resulting in a long list
of bugs and incorrect behaviour(s). It also uses
ITIMER_VIRTUAL for its timer which results in the
timer being dependent on it running and the cpu
load.

This patch fixes this by moving to posix high resolution
timers firing off CLOCK_MONOTONIC and relaying the timer
correctly to the UML userspace.

Fixes:
 - crashes when hosts suspends/resumes
 - broken userspace timers - effecive ~40Hz instead
   of what they should be. Note - this modifies skas behavior
   by no longer setting an itimer per clone(). Timer events
   are relayed instead.
 - kernel network packet scheduling disciplines
 - tcp behaviour especially under load
 - various timer related corner cases

Finally, overall responsiveness of userspace is better.

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Anton Ivanov <aivanov@brocade.com>
[rw: massaged commit message]
Signed-off-by: Richard Weinberger <richard@nod.at>
um: Remove SKAS3/4 support 2015-04-13T19:00:53+00:00 Richard Weinberger richard@nod.at 2015-03-18T20:31:27+00:00 d0b5e15f0c0fdd759dd3dd48dc2dc2e7199e0da0 Before we had SKAS0 UML had two modes of operation TT (tracing thread) and SKAS3/4 (separated kernel address space). TT was known to be insecure and got removed a long time ago. SKAS3/4 required a few (3 or 4) patches on the host side which never went mainline. The last host patch is 10 years old. With SKAS0 mode (separated kernel address space using 0 host patches), default since 2005, SKAS3/4 is obsolete and can be removed. Signed-off-by: Richard Weinberger <richard@nod.at> 
Before we had SKAS0 UML had two modes of operation
TT (tracing thread) and SKAS3/4 (separated kernel address space).
TT was known to be insecure and got removed a long time ago.
SKAS3/4 required a few (3 or 4) patches on the host side which never went
mainline. The last host patch is 10 years old.

With SKAS0 mode (separated kernel address space using 0 host patches),
default since 2005, SKAS3/4 is obsolete and can be removed.

Signed-off-by: Richard Weinberger <richard@nod.at>
um: Cleanup SIGTERM handling 2013-09-07T08:56:58+00:00 Richard Weinberger richard@nod.at 2013-08-18T11:30:08+00:00 91d44ff860a9e9c0db81a89cbc24fa31fbd8e6d3 Richard reported that some UML processes survive if the UML main process receives a SIGTERM. This issue was caused by a wrongly placed signal(SIGTERM, SIG_DFL) in init_new_thread_signals(). It disabled the UML exit handler accidently for some processes. The correct solution is to disable the fatal handler for all UML helper threads/processes. Such that last_ditch_exit() does not get called multiple times and all processes can exit due to SIGTERM. Reported-and-tested-by: Richard W.M. Jones <rjones@redhat.com> Signed-off-by: Richard Weinberger <richard@nod.at> 
Richard reported that some UML processes survive if the UML
main process receives a SIGTERM.
This issue was caused by a wrongly placed signal(SIGTERM, SIG_DFL)
in init_new_thread_signals().
It disabled the UML exit handler accidently for some processes.
The correct solution is to disable the fatal handler for all
UML helper threads/processes.
Such that last_ditch_exit() does not get called multiple times
and all processes can exit due to SIGTERM.

Reported-and-tested-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
um: Implement probe_kernel_read() 2013-09-07T08:38:34+00:00 Richard Weinberger richard@nod.at 2013-08-17T16:46:00+00:00 f75b1b1bedfb498cc43a992ce4d7ed8df3b1e770 UML needs it's own probe_kernel_read() to handle kernel mode faults correctly. The implementation uses mincore() on the host side to detect whether a page is owned by the UML kernel process. This fixes also a possible crash when sysrq-t is used. Starting with 3.10 sysrq-t calls probe_kernel_read() to read details from the kernel workers. As kernel worker are completely async pointers may turn NULL while reading them. Cc: <stian@nixia.no> Cc: <tj@kernel.org> Cc: <stable@vger.kernel.org> # 3.10.x Signed-off-by: Richard Weinberger <richard@nod.at> 
UML needs it's own probe_kernel_read() to handle kernel
mode faults correctly.
The implementation uses mincore() on the host side to detect
whether a page is owned by the UML kernel process.

This fixes also a possible crash when sysrq-t is used.
Starting with 3.10 sysrq-t calls probe_kernel_read() to
read details from the kernel workers. As kernel worker are
completely async pointers may turn NULL while reading them.

Cc: <stian@nixia.no>
Cc: <tj@kernel.org>
Cc: <stable@vger.kernel.org> # 3.10.x
Signed-off-by: Richard Weinberger <richard@nod.at>