| 3f67987c | 07-Apr-2023 |
Gregory Price <gourry.memverge@gmail.com> |
ptrace: Provide set/get interface for syscall user dispatch
The syscall user dispatch configuration can only be set by the task itself,
but lacks a ptrace set/get interface which makes it impossible
ptrace: Provide set/get interface for syscall user dispatch
The syscall user dispatch configuration can only be set by the task itself,
but lacks a ptrace set/get interface which makes it impossible to implement
checkpoint/restore for it.
Add the required ptrace requests and the get/set functions in the syscall
user dispatch code to make that possible.
Signed-off-by: Gregory Price <gregory.price@memverge.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20230407171834.3558-4-gregory.price@memverge.com
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| 463b7715 | 07-Apr-2023 |
Gregory Price <gourry.memverge@gmail.com> |
syscall_user_dispatch: Untag selector address before access_ok()
To support checkpoint/restart, ptrace must be able to set the selector
of the tracee. The selector is a user pointer that may be sub
syscall_user_dispatch: Untag selector address before access_ok()
To support checkpoint/restart, ptrace must be able to set the selector
of the tracee. The selector is a user pointer that may be subject to
memory tagging extensions on some architectures (namely ARM MTE).
access_ok() clears memory tags for tagged addresses if the current task has
memory tagging enabled.
This obviously fails when ptrace modifies the selector of a tracee when
tracer and tracee do not have the same memory tagging enabled state.
Solve this by untagging the selector address before handing it to
access_ok(), like other ptrace functions which modify tracee pointers do.
Obviously a tracer can set an invalid selector address for the tracee, but
that's independent of tagging and a general capability of the tracer.
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Gregory Price <gregory.price@memverge.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/all/ZCWXE04nLZ4pXEtM@arm.com/
Link: https://lore.kernel.org/r/20230407171834.3558-3-gregory.price@memverge.com
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| b4165140 | 15-Mar-2023 |
Frederic Weisbecker <frederic@kernel.org> |
entry/rcu: Check TIF_RESCHED _after_ delayed RCU wake-up
RCU sometimes needs to perform a delayed wake up for specific kthreads
handling offloaded callbacks (RCU_NOCB). These wakeups are performed
entry/rcu: Check TIF_RESCHED _after_ delayed RCU wake-up
RCU sometimes needs to perform a delayed wake up for specific kthreads
handling offloaded callbacks (RCU_NOCB). These wakeups are performed
by timers and upon entry to idle (also to guest and to user on nohz_full).
However the delayed wake-up on kernel exit is actually performed after
the thread flags are fetched towards the fast path check for work to
do on exit to user. As a result, and if there is no other pending work
to do upon that kernel exit, the current task will resume to userspace
with TIF_RESCHED set and the pending wake up ignored.
Fix this with fetching the thread flags _after_ the delayed RCU-nocb
kthread wake-up.
Fixes: 47b8ff194c1f ("entry: Explicitly flush pending rcuog wakeup before last rescheduling point")
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230315194349.10798-3-joel@joelfernandes.org
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| 7c5d8fa6 | 09-Feb-2022 |
Eric W. Biederman <ebiederm@xmission.com> |
task_work: Decouple TIF_NOTIFY_SIGNAL and task_work
There are a small handful of reasons besides pending signals that the
kernel might want to break out of interruptible sleeps. The flag
TIF_NOTIFY
task_work: Decouple TIF_NOTIFY_SIGNAL and task_work
There are a small handful of reasons besides pending signals that the
kernel might want to break out of interruptible sleeps. The flag
TIF_NOTIFY_SIGNAL and the helpers that set and clear TIF_NOTIFY_SIGNAL
provide that the infrastructure for breaking out of interruptible
sleeps and entering the return to user space slow path for those
cases.
Expand tracehook_notify_signal inline in it's callers and remove it,
which makes clear that TIF_NOTIFY_SIGNAL and task_work are separate
concepts.
Update the comment on set_notify_signal to more accurately describe
it's purpose.
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20220309162454.123006-9-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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| 0cfcb2b9 | 27-Jan-2022 |
Eric W. Biederman <ebiederm@xmission.com> |
ptrace: Remove arch_syscall_{enter,exit}_tracehook
These functions are alwasy one-to-one wrappers around
ptrace_report_syscall_entry and ptrace_report_syscall_exit.
So directly call the functions th
ptrace: Remove arch_syscall_{enter,exit}_tracehook
These functions are alwasy one-to-one wrappers around
ptrace_report_syscall_entry and ptrace_report_syscall_exit.
So directly call the functions they are wrapping instead.
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20220309162454.123006-4-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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