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Diffstat (limited to 'kernel')
-rw-r--r--kernel/events/core.c12
-rw-r--r--kernel/fork.c10
-rw-r--r--kernel/futex.c16
-rw-r--r--kernel/kthread.c3
-rw-r--r--kernel/signal.c19
-rw-r--r--kernel/trace/ring_buffer.c58
-rw-r--r--kernel/trace/trace.c2
-rw-r--r--kernel/trace/trace.h26
-rw-r--r--kernel/trace/trace_selftest.c9
9 files changed, 113 insertions, 42 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 09e1cc22221f..1b60f9c508c9 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9415,6 +9415,7 @@ perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
int fpos = token == IF_SRC_FILE ? 2 : 1;
+ kfree(filename);
filename = match_strdup(&args[fpos]);
if (!filename) {
ret = -ENOMEM;
@@ -9461,16 +9462,13 @@ perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
*/
ret = -EOPNOTSUPP;
if (!event->ctx->task)
- goto fail_free_name;
+ goto fail;
/* look up the path and grab its inode */
ret = kern_path(filename, LOOKUP_FOLLOW,
&filter->path);
if (ret)
- goto fail_free_name;
-
- kfree(filename);
- filename = NULL;
+ goto fail;
ret = -EINVAL;
if (!filter->path.dentry ||
@@ -9490,13 +9488,13 @@ perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
if (state != IF_STATE_ACTION)
goto fail;
+ kfree(filename);
kfree(orig);
return 0;
-fail_free_name:
- kfree(filename);
fail:
+ kfree(filename);
free_filters_list(filters);
kfree(orig);
diff --git a/kernel/fork.c b/kernel/fork.c
index e3d5963d8c6f..419fff8eb9e5 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2100,14 +2100,9 @@ static __latent_entropy struct task_struct *copy_process(
/* ok, now we should be set up.. */
p->pid = pid_nr(pid);
if (clone_flags & CLONE_THREAD) {
- p->exit_signal = -1;
p->group_leader = current->group_leader;
p->tgid = current->tgid;
} else {
- if (clone_flags & CLONE_PARENT)
- p->exit_signal = current->group_leader->exit_signal;
- else
- p->exit_signal = args->exit_signal;
p->group_leader = p;
p->tgid = p->pid;
}
@@ -2152,9 +2147,14 @@ static __latent_entropy struct task_struct *copy_process(
if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) {
p->real_parent = current->real_parent;
p->parent_exec_id = current->parent_exec_id;
+ if (clone_flags & CLONE_THREAD)
+ p->exit_signal = -1;
+ else
+ p->exit_signal = current->group_leader->exit_signal;
} else {
p->real_parent = current;
p->parent_exec_id = current->self_exec_id;
+ p->exit_signal = args->exit_signal;
}
klp_copy_process(p);
diff --git a/kernel/futex.c b/kernel/futex.c
index 17fba7a986e0..9c4f9b868a49 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2511,10 +2511,22 @@ retry:
}
/*
- * Since we just failed the trylock; there must be an owner.
+ * The trylock just failed, so either there is an owner or
+ * there is a higher priority waiter than this one.
*/
newowner = rt_mutex_owner(&pi_state->pi_mutex);
- BUG_ON(!newowner);
+ /*
+ * If the higher priority waiter has not yet taken over the
+ * rtmutex then newowner is NULL. We can't return here with
+ * that state because it's inconsistent vs. the user space
+ * state. So drop the locks and try again. It's a valid
+ * situation and not any different from the other retry
+ * conditions.
+ */
+ if (unlikely(!newowner)) {
+ err = -EAGAIN;
+ goto handle_err;
+ }
} else {
WARN_ON_ONCE(argowner != current);
if (oldowner == current) {
diff --git a/kernel/kthread.c b/kernel/kthread.c
index bfbfa481be3a..e51f0006057d 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -873,7 +873,8 @@ void kthread_delayed_work_timer_fn(struct timer_list *t)
/* Move the work from worker->delayed_work_list. */
WARN_ON_ONCE(list_empty(&work->node));
list_del_init(&work->node);
- kthread_insert_work(worker, work, &worker->work_list);
+ if (!work->canceling)
+ kthread_insert_work(worker, work, &worker->work_list);
raw_spin_unlock_irqrestore(&worker->lock, flags);
}
diff --git a/kernel/signal.c b/kernel/signal.c
index 595a36ab87d0..8c97fc72d78b 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -391,16 +391,17 @@ static bool task_participate_group_stop(struct task_struct *task)
void task_join_group_stop(struct task_struct *task)
{
+ unsigned long mask = current->jobctl & JOBCTL_STOP_SIGMASK;
+ struct signal_struct *sig = current->signal;
+
+ if (sig->group_stop_count) {
+ sig->group_stop_count++;
+ mask |= JOBCTL_STOP_CONSUME;
+ } else if (!(sig->flags & SIGNAL_STOP_STOPPED))
+ return;
+
/* Have the new thread join an on-going signal group stop */
- unsigned long jobctl = current->jobctl;
- if (jobctl & JOBCTL_STOP_PENDING) {
- struct signal_struct *sig = current->signal;
- unsigned long signr = jobctl & JOBCTL_STOP_SIGMASK;
- unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
- if (task_set_jobctl_pending(task, signr | gstop)) {
- sig->group_stop_count++;
- }
- }
+ task_set_jobctl_pending(task, mask | JOBCTL_STOP_PENDING);
}
/*
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 67cdb401c6ce..6e5c6b023dc3 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -422,14 +422,16 @@ struct rb_event_info {
/*
* Used for which event context the event is in.
- * NMI = 0
- * IRQ = 1
- * SOFTIRQ = 2
- * NORMAL = 3
+ * TRANSITION = 0
+ * NMI = 1
+ * IRQ = 2
+ * SOFTIRQ = 3
+ * NORMAL = 4
*
* See trace_recursive_lock() comment below for more details.
*/
enum {
+ RB_CTX_TRANSITION,
RB_CTX_NMI,
RB_CTX_IRQ,
RB_CTX_SOFTIRQ,
@@ -2660,10 +2662,10 @@ rb_wakeups(struct ring_buffer *buffer, struct ring_buffer_per_cpu *cpu_buffer)
* a bit of overhead in something as critical as function tracing,
* we use a bitmask trick.
*
- * bit 0 = NMI context
- * bit 1 = IRQ context
- * bit 2 = SoftIRQ context
- * bit 3 = normal context.
+ * bit 1 = NMI context
+ * bit 2 = IRQ context
+ * bit 3 = SoftIRQ context
+ * bit 4 = normal context.
*
* This works because this is the order of contexts that can
* preempt other contexts. A SoftIRQ never preempts an IRQ
@@ -2686,6 +2688,30 @@ rb_wakeups(struct ring_buffer *buffer, struct ring_buffer_per_cpu *cpu_buffer)
* The least significant bit can be cleared this way, and it
* just so happens that it is the same bit corresponding to
* the current context.
+ *
+ * Now the TRANSITION bit breaks the above slightly. The TRANSITION bit
+ * is set when a recursion is detected at the current context, and if
+ * the TRANSITION bit is already set, it will fail the recursion.
+ * This is needed because there's a lag between the changing of
+ * interrupt context and updating the preempt count. In this case,
+ * a false positive will be found. To handle this, one extra recursion
+ * is allowed, and this is done by the TRANSITION bit. If the TRANSITION
+ * bit is already set, then it is considered a recursion and the function
+ * ends. Otherwise, the TRANSITION bit is set, and that bit is returned.
+ *
+ * On the trace_recursive_unlock(), the TRANSITION bit will be the first
+ * to be cleared. Even if it wasn't the context that set it. That is,
+ * if an interrupt comes in while NORMAL bit is set and the ring buffer
+ * is called before preempt_count() is updated, since the check will
+ * be on the NORMAL bit, the TRANSITION bit will then be set. If an
+ * NMI then comes in, it will set the NMI bit, but when the NMI code
+ * does the trace_recursive_unlock() it will clear the TRANSTION bit
+ * and leave the NMI bit set. But this is fine, because the interrupt
+ * code that set the TRANSITION bit will then clear the NMI bit when it
+ * calls trace_recursive_unlock(). If another NMI comes in, it will
+ * set the TRANSITION bit and continue.
+ *
+ * Note: The TRANSITION bit only handles a single transition between context.
*/
static __always_inline int
@@ -2701,8 +2727,16 @@ trace_recursive_lock(struct ring_buffer_per_cpu *cpu_buffer)
bit = pc & NMI_MASK ? RB_CTX_NMI :
pc & HARDIRQ_MASK ? RB_CTX_IRQ : RB_CTX_SOFTIRQ;
- if (unlikely(val & (1 << (bit + cpu_buffer->nest))))
- return 1;
+ if (unlikely(val & (1 << (bit + cpu_buffer->nest)))) {
+ /*
+ * It is possible that this was called by transitioning
+ * between interrupt context, and preempt_count() has not
+ * been updated yet. In this case, use the TRANSITION bit.
+ */
+ bit = RB_CTX_TRANSITION;
+ if (val & (1 << (bit + cpu_buffer->nest)))
+ return 1;
+ }
val |= (1 << (bit + cpu_buffer->nest));
cpu_buffer->current_context = val;
@@ -2717,8 +2751,8 @@ trace_recursive_unlock(struct ring_buffer_per_cpu *cpu_buffer)
cpu_buffer->current_context - (1 << cpu_buffer->nest);
}
-/* The recursive locking above uses 4 bits */
-#define NESTED_BITS 4
+/* The recursive locking above uses 5 bits */
+#define NESTED_BITS 5
/**
* ring_buffer_nest_start - Allow to trace while nested
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 5b2a664812b1..2a357bda45cf 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3012,7 +3012,7 @@ static char *get_trace_buf(void)
/* Interrupts must see nesting incremented before we use the buffer */
barrier();
- return &buffer->buffer[buffer->nesting][0];
+ return &buffer->buffer[buffer->nesting - 1][0];
}
static void put_trace_buf(void)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 4055158c1dd2..fc3aa81a43e3 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -592,6 +592,12 @@ enum {
* function is called to clear it.
*/
TRACE_GRAPH_NOTRACE_BIT,
+
+ /*
+ * When transitioning between context, the preempt_count() may
+ * not be correct. Allow for a single recursion to cover this case.
+ */
+ TRACE_TRANSITION_BIT,
};
#define trace_recursion_set(bit) do { (current)->trace_recursion |= (1<<(bit)); } while (0)
@@ -646,14 +652,27 @@ static __always_inline int trace_test_and_set_recursion(int start, int max)
return 0;
bit = trace_get_context_bit() + start;
- if (unlikely(val & (1 << bit)))
- return -1;
+ if (unlikely(val & (1 << bit))) {
+ /*
+ * It could be that preempt_count has not been updated during
+ * a switch between contexts. Allow for a single recursion.
+ */
+ bit = TRACE_TRANSITION_BIT;
+ if (trace_recursion_test(bit))
+ return -1;
+ trace_recursion_set(bit);
+ barrier();
+ return bit + 1;
+ }
+
+ /* Normal check passed, clear the transition to allow it again */
+ trace_recursion_clear(TRACE_TRANSITION_BIT);
val |= 1 << bit;
current->trace_recursion = val;
barrier();
- return bit;
+ return bit + 1;
}
static __always_inline void trace_clear_recursion(int bit)
@@ -663,6 +682,7 @@ static __always_inline void trace_clear_recursion(int bit)
if (!bit)
return;
+ bit--;
bit = 1 << bit;
val &= ~bit;
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 69ee8ef12cee..0838c290ac7f 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -492,8 +492,13 @@ trace_selftest_function_recursion(void)
unregister_ftrace_function(&test_rec_probe);
ret = -1;
- if (trace_selftest_recursion_cnt != 1) {
- pr_cont("*callback not called once (%d)* ",
+ /*
+ * Recursion allows for transitions between context,
+ * and may call the callback twice.
+ */
+ if (trace_selftest_recursion_cnt != 1 &&
+ trace_selftest_recursion_cnt != 2) {
+ pr_cont("*callback not called once (or twice) (%d)* ",
trace_selftest_recursion_cnt);
goto out;
}
generated by cgit v1.2.3 (git 2.0.4) at 2024-05-01 12:11:42 +0000