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| author | Eric W. Biederman <ebiederm@xmission.com> | 2022-02-09 11:18:54 -0600 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2022-03-10 16:51:50 -0600 |
| commit | 7c5d8fa6fbb12a3f0eefe8762bfede508e147cb3 (patch) | |
| tree | 0abadafb76c2719b1632ae452a228909669edef3 | |
| parent | 8ba62d37949e248c698c26e0d82d72fda5d33ebf (diff) | |
| download | linux-stable-7c5d8fa6fbb12a3f0eefe8762bfede508e147cb3.tar.gz linux-stable-7c5d8fa6fbb12a3f0eefe8762bfede508e147cb3.tar.bz2 linux-stable-7c5d8fa6fbb12a3f0eefe8762bfede508e147cb3.zip | |
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>
| -rw-r--r-- | fs/io-wq.c | 4 | ||||
| -rw-r--r-- | fs/io_uring.c | 4 | ||||
| -rw-r--r-- | include/linux/tracehook.h | 15 | ||||
| -rw-r--r-- | kernel/entry/kvm.c | 7 |
4 files changed, 13 insertions, 17 deletions
diff --git a/fs/io-wq.c b/fs/io-wq.c index bb7f161bb19c..8b9147873c2c 100644 --- a/fs/io-wq.c +++ b/fs/io-wq.c @@ -515,7 +515,9 @@ static bool io_flush_signals(void) { if (unlikely(test_thread_flag(TIF_NOTIFY_SIGNAL))) { __set_current_state(TASK_RUNNING); - tracehook_notify_signal(); + clear_notify_signal(); + if (task_work_pending(current)) + task_work_run(); return true; } return false; diff --git a/fs/io_uring.c b/fs/io_uring.c index e85261079a78..d5fbae1030f9 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2592,7 +2592,9 @@ static inline bool io_run_task_work(void) { if (test_thread_flag(TIF_NOTIFY_SIGNAL) || task_work_pending(current)) { __set_current_state(TASK_RUNNING); - tracehook_notify_signal(); + clear_notify_signal(); + if (task_work_pending(current)) + task_work_run(); return true; } diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index b44a7820c468..e5d676e841e3 100644 --- a/include/linux/tracehook.h +++ b/include/linux/tracehook.h @@ -113,19 +113,8 @@ static inline void clear_notify_signal(void) } /* - * called by exit_to_user_mode_loop() if ti_work & _TIF_NOTIFY_SIGNAL. This - * is currently used by TWA_SIGNAL based task_work, which requires breaking - * wait loops to ensure that task_work is noticed and run. - */ -static inline void tracehook_notify_signal(void) -{ - clear_notify_signal(); - if (task_work_pending(current)) - task_work_run(); -} - -/* - * Called when we have work to process from exit_to_user_mode_loop() + * Called to break out of interruptible wait loops, and enter the + * exit_to_user_mode_loop(). */ static inline void set_notify_signal(struct task_struct *task) { diff --git a/kernel/entry/kvm.c b/kernel/entry/kvm.c index cabf36a489e4..3ab5f98988c3 100644 --- a/kernel/entry/kvm.c +++ b/kernel/entry/kvm.c @@ -8,8 +8,11 @@ static int xfer_to_guest_mode_work(struct kvm_vcpu *vcpu, unsigned long ti_work) do { int ret; - if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) - tracehook_notify_signal(); + if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) { + clear_notify_signal(); + if (task_work_pending(current)) + task_work_run(); + } if (ti_work & _TIF_SIGPENDING) { kvm_handle_signal_exit(vcpu); |