[PATCH] init_module.2: Add ETXTBSY error for finit_module

Since kernel commit[1], finit_module fails with ETXTBSY error if fd has write permission.
Since kernel commit[2], finit_module fails with EBADF error if fd doesn't have read permission.

So we can use read-write permission to trigger ETXTBSY error all the time since linux 4.7.

[1]https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=39d637af
[2]https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=032146cd

Signed-off-by: Yang Xu <xuyang2018.jy@fujitsu.com>
---
 man2/init_module.2 | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/man2/init_module.2 b/man2/init_module.2
index aac0c6631..2bcbaf4c3 100644
--- a/man2/init_module.2
+++ b/man2/init_module.2

@@ -242,6 +242,13 @@ is invalid.
 .B ENOEXEC
 .I fd
 does not refer to an open file.
+.TP
+.BR ETXTBSY " (since Linux 4.7)"
+.\" commit 39d637af5aa7577f655c58b9e55587566c63a0af
+The file referred to by
+.I fd
+is opened for read-write.
+.
 .PP
 In addition to the above errors, if the module's
 .I init

-- 
2.23.0