linux-toradex.git/kernel/livepatch/transition.c, branch v5.19-rc1

Merge tag 'ptrace-cleanups-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2022-03-29T00:29:53+00:00

Pull ptrace cleanups from Eric Biederman:
 "This set of changes removes tracehook.h, moves modification of all of
  the ptrace fields inside of siglock to remove races, adds a missing
  permission check to ptrace.c

  The removal of tracehook.h is quite significant as it has been a major
  source of confusion in recent years. Much of that confusion was around
  task_work and TIF_NOTIFY_SIGNAL (which I have now decoupled making the
  semantics clearer).

  For people who don't know tracehook.h is a vestiage of an attempt to
  implement uprobes like functionality that was never fully merged, and
  was later superseeded by uprobes when uprobes was merged. For many
  years now we have been removing what tracehook functionaly a little
  bit at a time. To the point where anything left in tracehook.h was
  some weird strange thing that was difficult to understand"

* tag 'ptrace-cleanups-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  ptrace: Remove duplicated include in ptrace.c
  ptrace: Check PTRACE_O_SUSPEND_SECCOMP permission on PTRACE_SEIZE
  ptrace: Return the signal to continue with from ptrace_stop
  ptrace: Move setting/clearing ptrace_message into ptrace_stop
  tracehook: Remove tracehook.h
  resume_user_mode: Move to resume_user_mode.h
  resume_user_mode: Remove #ifdef TIF_NOTIFY_RESUME in set_notify_resume
  signal: Move set_notify_signal and clear_notify_signal into sched/signal.h
  task_work: Decouple TIF_NOTIFY_SIGNAL and task_work
  task_work: Call tracehook_notify_signal from get_signal on all architectures
  task_work: Introduce task_work_pending
  task_work: Remove unnecessary include from posix_timers.h
  ptrace: Remove tracehook_signal_handler
  ptrace: Remove arch_syscall_{enter,exit}_tracehook
  ptrace: Create ptrace_report_syscall_{entry,exit} in ptrace.h
  ptrace/arm: Rename tracehook_report_syscall report_syscall
  ptrace: Move ptrace_report_syscall into ptrace.h

livepatch: Don't block removal of patches that are safe to unload

2022-03-17T18:02:30+00:00

module_put() is not called for a patch with "forced" flag. It should
block the removal of the livepatch module when the code might still
be in use after forced transition.

klp_force_transition() currently sets "forced" flag for all patches on
the list.

In fact, any patch can be safely unloaded when it passed through
the consistency model in KLP_UNPATCHED transition.

In other words, the "forced" flag must be set only for livepatches
that are being removed. In particular, set the "forced" flag:

  + only for klp_transition_patch when the transition to KLP_UNPATCHED
    state was forced.

  + all replaced patches when the transition to KLP_PATCHED state was
    forced and the patch was replacing the existing patches.

Signed-off-by: Chengming Zhou 
Acked-by: Joe Lawrence 
Reviewed-by: Petr Mladek 
Tested-by: Petr Mladek 
[mbenes@suse.cz: wording improvements]
Signed-off-by: Petr Mladek 
Link: https://lore.kernel.org/r/20220312152220.88127-1-zhouchengming@bytedance.com

tracehook: Remove tracehook.h

2022-03-10T22:51:51+00:00

Now that all of the definitions have moved out of tracehook.h into
ptrace.h, sched/signal.h, resume_user_mode.h there is nothing left in
tracehook.h so remove it.

Update the few files that were depending upon tracehook.h to bring in
definitions to use the headers they need directly.

Reviewed-by: Kees Cook 
Link: https://lkml.kernel.org/r/20220309162454.123006-13-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman"

sched,livepatch: Use wake_up_if_idle()

2021-10-14T11:09:25+00:00

Make sure to prod idle CPUs so they call klp_update_patch_state().

Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Petr Mladek 
Acked-by: Miroslav Benes 
Acked-by: Vasily Gorbik 
Tested-by: Petr Mladek 
Tested-by: Vasily Gorbik  # on s390
Link: https://lkml.kernel.org/r/20210929151723.162004989@infradead.org

sched,livepatch: Use task_call_func()

2021-10-07T11:51:15+00:00

Instead of frobbing around with scheduler internals, use the shiny new
task_call_func() interface.

Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Petr Mladek 
Acked-by: Miroslav Benes 
Acked-by: Vasily Gorbik 
Tested-by: Petr Mladek 
Tested-by: Vasily Gorbik  # on s390
Link: https://lkml.kernel.org/r/20210929152428.709906138@infradead.org

livepatch: Replace deprecated CPU-hotplug functions.

2021-08-19T10:00:24+00:00

The functions get_online_cpus() and put_online_cpus() have been
deprecated during the CPU hotplug rework. They map directly to
cpus_read_lock() and cpus_read_unlock().

Replace deprecated CPU-hotplug functions with the official version.
The behavior remains unchanged.

Cc: Josh Poimboeuf 
Cc: Jiri Kosina 
Cc: Miroslav Benes 
Cc: Petr Mladek 
Cc: Joe Lawrence 
Cc: live-patching@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior 
Reviewed-by: Petr Mladek 
Signed-off-by: Jiri Kosina

livepatch: Replace the fake signal sending with TIF_NOTIFY_SIGNAL infrastructure

2021-03-30T07:40:21+00:00

Livepatch sends a fake signal to all remaining blocking tasks of a
running transition after a set period of time. It uses TIF_SIGPENDING
flag for the purpose. Commit 12db8b690010 ("entry: Add support for
TIF_NOTIFY_SIGNAL") added a generic infrastructure to achieve the same.
Replace our bespoke solution with the generic one.

Reviewed-by: Jens Axboe 
Reviewed-by: Petr Mladek 
Acked-by: Joe Lawrence 
Signed-off-by: Miroslav Benes 
Signed-off-by: Jiri Kosina

livepatch: Keep replaced patches until post_patch callback is called

2019-11-01T12:08:08+00:00

Pre/post (un)patch callbacks might manipulate the system state. Cumulative
livepatches might need to take over the changes made by the replaced
ones. For this they might need to access some data stored or referenced
by the old livepatches.

Therefore the replaced livepatches have to stay around until post_patch()
callback is called. It is achieved by calling the free functions later.
It is the same location where disabled livepatches have already been
freed.

Link: http://lkml.kernel.org/r/20191030154313.13263-2-pmladek@suse.com
To: Jiri Kosina 
Cc: Kamalesh Babulal 
Cc: Nicolai Stange 
Cc: live-patching@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Miroslav Benes 
Acked-by: Joe Lawrence 
Acked-by: Josh Poimboeuf 
Signed-off-by: Petr Mladek

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching

2019-07-11T22:30:05+00:00

Pull livepatching updates from Jiri Kosina:

 - stacktrace handling improvements from Miroslav benes

 - debug output improvements from Petr Mladek

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching:
  livepatch: Remove duplicate warning about missing reliable stacktrace support
  Revert "livepatch: Remove reliable stacktrace check in klp_try_switch_task()"
  stacktrace: Remove weak version of save_stack_trace_tsk_reliable()
  livepatch: Use static buffer for debugging messages under rq lock
  livepatch: Remove stale kobj_added entries from kernel-doc descriptions

livepatch: Remove duplicate warning about missing reliable stacktrace support

2019-06-20T14:19:13+00:00

WARN_ON_ONCE() could not be called safely under rq lock because
of console deadlock issues. Moreover WARN_ON_ONCE() is superfluous in
klp_check_stack(), because stack_trace_save_tsk_reliable() cannot return
-ENOSYS thanks to klp_have_reliable_stack() check in
klp_try_switch_task().

[ mbenes: changelog edited ]
Signed-off-by: Miroslav Benes 
Acked-by: Josh Poimboeuf 
Reviewed-by: Kamalesh Babulal 
Signed-off-by: Petr Mladek