[PATCH] module: fix failed to rmmod kernel module when it's name is too long

[Xie XiuQi]

When the name of kernel module is more than 56 chars (include 56),
the module could be insmod successfully, but failed to rmmod.

$ strace rmmod tst_1111111111222222222233333333334444444444555555555566
...
open("/sys/module/tst_1111111111222222222233333333334444444444555555555566/initstate", O_RDONLY|O_CLOEXEC) = 3
read(3, "live\n", 31)                   = 5
read(3, "", 26)                         = 0
close(3)                                = 0
openat(AT_FDCWD, "/sys/module/tst_1111111111222222222233333333334444444444555555555566/holders", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 3
getdents(3, /* 2 entries */, 32768)     = 48
getdents(3, /* 0 entries */, 32768)     = 0
close(3)                                = 0
open("/sys/module/tst_1111111111222222222233333333334444444444555555555566/refcnt", O_RDONLY|O_CLOEXEC) = 3
read(3, "0\n", 31)                      = 2
read(3, "", 29)                         = 0
close(3)                                = 0
delete_module("tst_1111111111222222222233333333334444444444555555555566", O_RDONLY|O_NONBLOCK) = -1 ENOENT (No such file or directory)
write(2, "rmmod: ERROR: could not remove '"..., 117rmmod: ERROR: could not remove 'tst_1111111111222222222233333333334444444444555555555566': No such file or directory
) = 117
write(2, "rmmod: ERROR: could not remove m"..., 122rmmod: ERROR: could not remove module tst_1111111111222222222233333333334444444444555555555566: No such file or directory
) = 122
exit_group(1)                           = ?
+++ exited with 1 +++

In this patch, we just set the last char to '\0', to make sure
the name has the tailing '\0'.

Reported-by: Zhang Liguang <zhangliguang@xxxxxxxxxx>
Signed-off-by: Xie XiuQi <xiexiuqi@xxxxxxxxxx>
---
 kernel/module.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/module.c b/kernel/module.c
index 0e54d5b..3eac266 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2928,6 +2928,7 @@ static struct module *setup_load_info(struct load_info *info, int flags)
 	}
 	/* This is temporary: point mod into copy of data. */
 	mod = (void *)info->sechdrs[info->index.mod].sh_addr;
+	mod->name[MODULE_NAME_LEN - 1] = '\0';
 
 	if (info->index.sym == 0) {
 		pr_warn("%s: module has no symbols (stripped?)\n", mod->name);
-- 
1.8.3.1