[PATCH 4.19.y RESEND] erofs: fix up erofs_lookup tracepoint

[Gao Xiang]

commit 93368aab0efc87288cac65e99c9ed2e0ffc9e7d0 upstream.

Fix up a misuse that the filename pointer isn't always valid in
the ring buffer, and we should copy the content instead.

Link: https://lore.kernel.org/r/20210921143531.81356-1-hsiangkao@linux.alibaba.com
Fixes: 13f06f48f7bf ("staging: erofs: support tracepoint")
Cc: stable at vger.kernel.org # 4.19+
Reviewed-by: Chao Yu <chao at kernel.org>
[ Gao Xiang: resolve trivial conflicts for 4.19.y. ]
Signed-off-by: Gao Xiang <hsiangkao at linux.alibaba.com>
---
add missing upstream commit id...

 drivers/staging/erofs/include/trace/events/erofs.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/erofs/include/trace/events/erofs.h b/drivers/staging/erofs/include/trace/events/erofs.h
index 5aead93a762f..852c94176d1b 100644
--- a/drivers/staging/erofs/include/trace/events/erofs.h
+++ b/drivers/staging/erofs/include/trace/events/erofs.h
@@ -32,20 +32,20 @@ TRACE_EVENT(erofs_lookup,
 	TP_STRUCT__entry(
 		__field(dev_t,		dev	)
 		__field(erofs_nid_t,	nid	)
-		__field(const char *,	name	)
+		__string(name,		dentry->d_name.name	)
 		__field(unsigned int,	flags	)
 	),
 
 	TP_fast_assign(
 		__entry->dev	= dir->i_sb->s_dev;
 		__entry->nid	= EROFS_V(dir)->nid;
-		__entry->name	= dentry->d_name.name;
+		__assign_str(name, dentry->d_name.name);
 		__entry->flags	= flags;
 	),
 
 	TP_printk("dev = (%d,%d), pnid = %llu, name:%s, flags:%x",
 		show_dev_nid(__entry),
-		__entry->name,
+		__get_str(name),
 		__entry->flags)
 );
 
-- 
2.24.4