Merge tag 'nand/fixes-for-4.12-rc3' of git://git.infradead.org/linux-mtd into MTD

From Boris:
"""
This pull request contains several fixes to the core and the tango
driver.

tango fixes:
 * Add missing MODULE_DEVICE_TABLE() in tango_nand.c
 * Update the number of corrected bitflips

core fixes:
 * Fix a long standing memory leak in nand_scan_tail()
 * Fix several bugs introduced by the per-vendor init/detection
   infrastructure (introduced in 4.12)
 * Add a static specifier to nand_ooblayout_lp_hamming_ops definition
"""

1 files changed, 32 insertions, 2 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c4536c449021..1122f151466f 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1558,7 +1558,7 @@ static __init int init_trace_selftests(void)
 
         return 0;
 }
-early_initcall(init_trace_selftests);
+core_initcall(init_trace_selftests);
 #else
 static inline int run_tracer_selftest(struct tracer *type)
 {
@@ -2568,7 +2568,36 @@ static inline void ftrace_trace_stack(struct trace_array *tr,
 void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
                    int pc)
 {
-        __ftrace_trace_stack(tr->trace_buffer.buffer, flags, skip, pc, NULL);
+        struct ring_buffer *buffer = tr->trace_buffer.buffer;
+
+        if (rcu_is_watching()) {
+                __ftrace_trace_stack(buffer, flags, skip, pc, NULL);
+                return;
+        }
+
+        /*
+         * When an NMI triggers, RCU is enabled via rcu_nmi_enter(),
+         * but if the above rcu_is_watching() failed, then the NMI
+         * triggered someplace critical, and rcu_irq_enter() should
+         * not be called from NMI.
+         */
+        if (unlikely(in_nmi()))
+                return;
+
+        /*
+         * It is possible that a function is being traced in a
+         * location that RCU is not watching. A call to
+         * rcu_irq_enter() will make sure that it is, but there's
+         * a few internal rcu functions that could be traced
+         * where that wont work either. In those cases, we just
+         * do nothing.
+         */
+        if (unlikely(rcu_irq_enter_disabled()))
+                return;
+
+        rcu_irq_enter_irqson();
+        __ftrace_trace_stack(buffer, flags, skip, pc, NULL);
+        rcu_irq_exit_irqson();
 }
 
 /**
@@ -7550,6 +7579,7 @@ static int instance_rmdir(const char *name)
         }
 
         tracing_set_nop(tr);
+        clear_ftrace_function_probes(tr);
         event_trace_del_tracer(tr);
         ftrace_clear_pids(tr);
         ftrace_destroy_function_files(tr);