diff options
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/events/core.c | 41 | ||||
-rw-r--r-- | kernel/irq/dummychip.c | 1 | ||||
-rw-r--r-- | kernel/time/clockevents.c | 6 | ||||
-rw-r--r-- | kernel/trace/trace_output.c | 3 |
4 files changed, 37 insertions, 14 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 81aa3a4..1a3bf48 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -913,10 +913,30 @@ static void put_ctx(struct perf_event_context *ctx) * Those places that change perf_event::ctx will hold both * perf_event_ctx::mutex of the 'old' and 'new' ctx value. * - * Lock ordering is by mutex address. There is one other site where - * perf_event_context::mutex nests and that is put_event(). But remember that - * that is a parent<->child context relation, and migration does not affect - * children, therefore these two orderings should not interact. + * Lock ordering is by mutex address. There are two other sites where + * perf_event_context::mutex nests and those are: + * + * - perf_event_exit_task_context() [ child , 0 ] + * __perf_event_exit_task() + * sync_child_event() + * put_event() [ parent, 1 ] + * + * - perf_event_init_context() [ parent, 0 ] + * inherit_task_group() + * inherit_group() + * inherit_event() + * perf_event_alloc() + * perf_init_event() + * perf_try_init_event() [ child , 1 ] + * + * While it appears there is an obvious deadlock here -- the parent and child + * nesting levels are inverted between the two. This is in fact safe because + * life-time rules separate them. That is an exiting task cannot fork, and a + * spawning task cannot (yet) exit. + * + * But remember that that these are parent<->child context relations, and + * migration does not affect children, therefore these two orderings should not + * interact. * * The change in perf_event::ctx does not affect children (as claimed above) * because the sys_perf_event_open() case will install a new event and break @@ -3657,9 +3677,6 @@ static void perf_remove_from_owner(struct perf_event *event) } } -/* - * Called when the last reference to the file is gone. - */ static void put_event(struct perf_event *event) { struct perf_event_context *ctx; @@ -3697,6 +3714,9 @@ int perf_event_release_kernel(struct perf_event *event) } EXPORT_SYMBOL_GPL(perf_event_release_kernel); +/* + * Called when the last reference to the file is gone. + */ static int perf_release(struct inode *inode, struct file *file) { put_event(file->private_data); @@ -7364,7 +7384,12 @@ static int perf_try_init_event(struct pmu *pmu, struct perf_event *event) return -ENODEV; if (event->group_leader != event) { - ctx = perf_event_ctx_lock(event->group_leader); + /* + * This ctx->mutex can nest when we're called through + * inheritance. See the perf_event_ctx_lock_nested() comment. + */ + ctx = perf_event_ctx_lock_nested(event->group_leader, + SINGLE_DEPTH_NESTING); BUG_ON(!ctx); } diff --git a/kernel/irq/dummychip.c b/kernel/irq/dummychip.c index 988dc58..2feb6fe 100644 --- a/kernel/irq/dummychip.c +++ b/kernel/irq/dummychip.c @@ -57,5 +57,6 @@ struct irq_chip dummy_irq_chip = { .irq_ack = noop, .irq_mask = noop, .irq_unmask = noop, + .flags = IRQCHIP_SKIP_SET_WAKE, }; EXPORT_SYMBOL_GPL(dummy_irq_chip); diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index 11dc22a..637a094 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -117,11 +117,7 @@ static int __clockevents_set_state(struct clock_event_device *dev, /* Transition with new state-specific callbacks */ switch (state) { case CLOCK_EVT_STATE_DETACHED: - /* - * This is an internal state, which is guaranteed to go from - * SHUTDOWN to DETACHED. No driver interaction required. - */ - return 0; + /* The clockevent device is getting replaced. Shut it down. */ case CLOCK_EVT_STATE_SHUTDOWN: return dev->set_state_shutdown(dev); diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index 692bf71..25a086b 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -178,12 +178,13 @@ ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len) EXPORT_SYMBOL(ftrace_print_hex_seq); const char * -ftrace_print_array_seq(struct trace_seq *p, const void *buf, int buf_len, +ftrace_print_array_seq(struct trace_seq *p, const void *buf, int count, size_t el_size) { const char *ret = trace_seq_buffer_ptr(p); const char *prefix = ""; void *ptr = (void *)buf; + size_t buf_len = count * el_size; trace_seq_putc(p, '{'); |