From 7f62d40d9cb50fd146fe8ff071f98fa3c1855083 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 9 Feb 2022 08:52:41 -0600 Subject: [PATCH] task_work: Introduce task_work_pending Wrap the test of task->task_works in a helper function to make it clear what is being tested. All of the other readers of task->task_work use READ_ONCE and this is even necessary on current as other processes can update task->task_work. So for consistency I have added READ_ONCE into task_work_pending. Reviewed-by: Kees Cook Link: https://lkml.kernel.org/r/20220309162454.123006-7-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" --- fs/io_uring.c | 6 +++--- include/linux/task_work.h | 5 +++++ include/linux/tracehook.h | 4 ++-- kernel/signal.c | 4 ++-- kernel/task_work.c | 2 +- 5 files changed, 13 insertions(+), 8 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index e54c4127422e..e85261079a78 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2590,7 +2590,7 @@ static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx) static inline bool io_run_task_work(void) { - if (test_thread_flag(TIF_NOTIFY_SIGNAL) || current->task_works) { + if (test_thread_flag(TIF_NOTIFY_SIGNAL) || task_work_pending(current)) { __set_current_state(TASK_RUNNING); tracehook_notify_signal(); return true; @@ -7602,7 +7602,7 @@ static int io_sq_thread(void *data) } prepare_to_wait(&sqd->wait, &wait, TASK_INTERRUPTIBLE); - if (!io_sqd_events_pending(sqd) && !current->task_works) { + if (!io_sqd_events_pending(sqd) && !task_work_pending(current)) { bool needs_sched = true; list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) { @@ -10321,7 +10321,7 @@ static __cold void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, hlist_for_each_entry(req, list, hash_node) seq_printf(m, " op=%d, task_works=%d\n", req->opcode, - req->task->task_works != NULL); + task_work_pending(req->task)); } seq_puts(m, "CqOverflowList:\n"); diff --git a/include/linux/task_work.h b/include/linux/task_work.h index 5b8a93f288bb..897494b597ba 100644 --- a/include/linux/task_work.h +++ b/include/linux/task_work.h @@ -19,6 +19,11 @@ enum task_work_notify_mode { TWA_SIGNAL, }; +static inline bool task_work_pending(struct task_struct *task) +{ + return READ_ONCE(task->task_works); +} + int task_work_add(struct task_struct *task, struct callback_head *twork, enum task_work_notify_mode mode); diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index b77bf4917196..fa834a22e86e 100644 --- a/include/linux/tracehook.h +++ b/include/linux/tracehook.h @@ -90,7 +90,7 @@ static inline void tracehook_notify_resume(struct pt_regs *regs) * hlist_add_head(task->task_works); */ smp_mb__after_atomic(); - if (unlikely(current->task_works)) + if (unlikely(task_work_pending(current))) task_work_run(); #ifdef CONFIG_KEYS_REQUEST_CACHE @@ -115,7 +115,7 @@ static inline void tracehook_notify_signal(void) { clear_thread_flag(TIF_NOTIFY_SIGNAL); smp_mb__after_atomic(); - if (current->task_works) + if (task_work_pending(current)) task_work_run(); } diff --git a/kernel/signal.c b/kernel/signal.c index 0e0bd1c1068b..3b4cf25fb9b3 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2344,7 +2344,7 @@ static void ptrace_do_notify(int signr, int exit_code, int why) void ptrace_notify(int exit_code) { BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); - if (unlikely(current->task_works)) + if (unlikely(task_work_pending(current))) task_work_run(); spin_lock_irq(¤t->sighand->siglock); @@ -2626,7 +2626,7 @@ bool get_signal(struct ksignal *ksig) struct signal_struct *signal = current->signal; int signr; - if (unlikely(current->task_works)) + if (unlikely(task_work_pending(current))) task_work_run(); /* diff --git a/kernel/task_work.c b/kernel/task_work.c index 1698fbe6f0e1..cc6fccb0e24d 100644 --- a/kernel/task_work.c +++ b/kernel/task_work.c @@ -78,7 +78,7 @@ task_work_cancel_match(struct task_struct *task, struct callback_head *work; unsigned long flags; - if (likely(!task->task_works)) + if (likely(!task_work_pending(task))) return NULL; /* * If cmpxchg() fails we continue without updating pprev. -- 2.25.1