[PATCH AUTOSEL 4.9 7/7] lib: stackdepot: turn depot_lock spinlock to raw_spinlock

[Sasha Levin]

From: Zqiang <qiang.zhang@xxxxxxxxxxxxx>

[ Upstream commit 78564b9434878d686c5f88c4488b20cccbcc42bc ]

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 this calltrace:

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

Replace spinlock with raw_spinlock.

Link: https://lkml.kernel.org/r/20210329084009.27013-1-qiang.zhang@xxxxxxxxxxxxx
Signed-off-by: Zqiang <qiang.zhang@xxxxxxxxxxxxx>
Reported-by: Andrew Halaney <ahalaney@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
Cc: Vijayanand Jitta <vjitta@xxxxxxxxxxxxxx>
Cc: Vinayak Menon <vinmenon@xxxxxxxxxxxxxx>
Cc: Yogesh Lal <ylal@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 lib/stackdepot.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index 759ff419fe61..c519aa07d2e9 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -78,7 +78,7 @@ 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)
 {
@@ -253,7 +253,7 @@ depot_stack_handle_t depot_save_stack(struct stack_trace *trace,
 			prealloc = page_address(page);
 	}
 
-	spin_lock_irqsave(&depot_lock, flags);
+	raw_spin_lock_irqsave(&depot_lock, flags);
 
 	found = find_stack(*bucket, trace->entries, trace->nr_entries, hash);
 	if (!found) {
@@ -277,7 +277,7 @@ depot_stack_handle_t depot_save_stack(struct stack_trace *trace,
 		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. */
-- 
2.30.2