FAILED: patch "[PATCH] erofs: fix up erofs_lookup tracepoint" failed to apply to 4.19-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 93368aab0efc87288cac65e99c9ed2e0ffc9e7d0 Mon Sep 17 00:00:00 2001
From: Gao Xiang <hsiangkao@linux.alibaba.com>
Date: Tue, 21 Sep 2021 22:35:30 +0800
Subject: [PATCH] erofs: fix up erofs_lookup tracepoint

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@vger.kernel.org # 4.19+
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

diff --git a/include/trace/events/erofs.h b/include/trace/events/erofs.h
index bf9806fd1306..db4f2cec8360 100644
--- a/include/trace/events/erofs.h
+++ b/include/trace/events/erofs.h
@@ -35,20 +35,20 @@ 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_I(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)
 );