From: Sung-hun Kim <sfoon.kim@xxxxxxxxxxx>
commit e400be674a1a40e9dcb2e95f84d6c1fd2d88f31d upstream.
Since the commit 36e2c7421f02 ("fs: don't allow splice read/write
without explicit ops") is applied to the kernel, splice() and
sendfile() calls on the trace file (/sys/kernel/debug/tracing
/trace) return EINVAL.
This patch restores these system calls by initializing splice_read
in file_operations of the trace file. This patch only enables such
functionalities for the read case.
Link: https://lore.kernel.org/linux-trace-kernel/20230314013707.28814-1-sfoon.kim@xxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops")
Signed-off-by: Sung-hun Kim <sfoon.kim@xxxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/trace/trace.c | 2 ++
1 file changed, 2 insertions(+)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5119,6 +5119,8 @@ loff_t tracing_lseek(struct file *file,
static const struct file_operations tracing_fops = {
.open = tracing_open,
.read = seq_read,
+ .read_iter = seq_read_iter,
+ .splice_read = generic_file_splice_read,
.write = tracing_write_stub,
.llseek = tracing_lseek,
.release = tracing_release,
