[PATCH] lib: stackdepot: turn depot_lock spinlock to raw_spinlock

[qiang . zhang]

From: Zqiang <qiang.zhang@xxxxxxxxxxxxx>

[    2.670635] BUG: sleeping function called from invalid context
at kernel/locking/rtmutex.c:951
[    2.670638] in_atomic(): 0, irqs_disabled(): 1, non_block: 0,
pid: 19, name: pgdatinit0
[    2.670768] Call Trace:
[    2.670800]  dump_stack+0x93/0xc2
[    2.670826]  ___might_sleep.cold+0x1b2/0x1f1
[    2.670838]  rt_spin_lock+0x3b/0xb0
[    2.670838]  stack_depot_save+0x1b9/0x440
[    2.670838]  kasan_save_stack+0x32/0x40
[    2.670838]  kasan_record_aux_stack+0xa5/0xb0
[    2.670838]  __call_rcu+0x117/0x880
[    2.670838]  __exit_signal+0xafb/0x1180
[    2.670838]  release_task+0x1d6/0x480
[    2.670838]  exit_notify+0x303/0x750
[    2.670838]  do_exit+0x678/0xcf0
[    2.670838]  kthread+0x364/0x4f0
[    2.670838]  ret_from_fork+0x22/0x30

In RT system, the spin_lock will be replaced by sleepable
rt_mutex lock, in __call_rcu(), disable interrupts before
calling kasan_record_aux_stack(), will trigger above calltrace,
replace spinlock with raw_spinlock.

Reported-by: Andrew Halaney <ahalaney@xxxxxxxxxx>
Signed-off-by: Zqiang <qiang.zhang@xxxxxxxxxxxxx>
---
 lib/stackdepot.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index 49f67a0c6e5d..df9179f4f441 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -71,7 +71,7 @@ static void *stack_slabs[STACK_ALLOC_MAX_SLABS];
 static int depot_index;
 static int next_slab_inited;
 static size_t depot_offset;
-static DEFINE_SPINLOCK(depot_lock);
+static DEFINE_RAW_SPINLOCK(depot_lock);
 
 static bool init_stack_slab(void **prealloc)
 {
@@ -305,7 +305,7 @@ depot_stack_handle_t stack_depot_save(unsigned long *entries,
 			prealloc = page_address(page);
 	}
 
-	spin_lock_irqsave(&depot_lock, flags);
+	raw_spin_lock_irqsave(&depot_lock, flags);
 
 	found = find_stack(*bucket, entries, nr_entries, hash);
 	if (!found) {
@@ -329,7 +329,7 @@ depot_stack_handle_t stack_depot_save(unsigned long *entries,
 		WARN_ON(!init_stack_slab(&prealloc));
 	}
 
-	spin_unlock_irqrestore(&depot_lock, flags);
+	raw_spin_unlock_irqrestore(&depot_lock, flags);
 exit:
 	if (prealloc) {
 		/* Nobody used this memory, ok to free it. */
-- 
2.17.1