* [PATCH v4 1/4] selftests: kmod: Use variable NAME in kmod_test_0001()
2020-04-21 7:05 [PATCH v4 0/4] Fix some issues about kmod Tiezhu Yang
@ 2020-04-21 7:05 ` Tiezhu Yang
2020-04-21 7:05 ` [PATCH v4 2/4] kmod: Remove redundant "be an" in the comment Tiezhu Yang
` (3 subsequent siblings)
4 siblings, 0 replies; 9+ messages in thread
From: Tiezhu Yang @ 2020-04-21 7:05 UTC (permalink / raw)
To: Luis Chamberlain, Shuah Khan, Andrew Morton, Jessica Yu
Cc: linux-kselftest, linux-kernel, Markus Elfring, Xuefeng Li
Use the variable NAME instead of "\000" directly in kmod_test_0001().
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
v4:
- no changes
v3:
- no changes
v2:
- just add the Acked-by tag
tools/testing/selftests/kmod/kmod.sh | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/kmod/kmod.sh b/tools/testing/selftests/kmod/kmod.sh
index 3702dbc..da60c3b 100755
--- a/tools/testing/selftests/kmod/kmod.sh
+++ b/tools/testing/selftests/kmod/kmod.sh
@@ -341,7 +341,7 @@ kmod_test_0001_driver()
kmod_defaults_driver
config_num_threads 1
- printf '\000' >"$DIR"/config_test_driver
+ printf $NAME >"$DIR"/config_test_driver
config_trigger ${FUNCNAME[0]}
config_expect_result ${FUNCNAME[0]} MODULE_NOT_FOUND
}
@@ -352,7 +352,7 @@ kmod_test_0001_fs()
kmod_defaults_fs
config_num_threads 1
- printf '\000' >"$DIR"/config_test_fs
+ printf $NAME >"$DIR"/config_test_fs
config_trigger ${FUNCNAME[0]}
config_expect_result ${FUNCNAME[0]} -EINVAL
}
--
2.1.0
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH v4 2/4] kmod: Remove redundant "be an" in the comment
2020-04-21 7:05 [PATCH v4 0/4] Fix some issues about kmod Tiezhu Yang
2020-04-21 7:05 ` [PATCH v4 1/4] selftests: kmod: Use variable NAME in kmod_test_0001() Tiezhu Yang
@ 2020-04-21 7:05 ` Tiezhu Yang
2020-04-21 7:05 ` [PATCH v4 3/4] kmod: Return directly if module name is empty in request_module() Tiezhu Yang
` (2 subsequent siblings)
4 siblings, 0 replies; 9+ messages in thread
From: Tiezhu Yang @ 2020-04-21 7:05 UTC (permalink / raw)
To: Luis Chamberlain, Shuah Khan, Andrew Morton, Jessica Yu
Cc: linux-kselftest, linux-kernel, Markus Elfring, Xuefeng Li
There exists redundant "be an" in the comment, remove it.
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
v4:
- no changes
v3:
- no changes
v2:
- just add the Acked-by tag
kernel/kmod.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 37c3c4b..3cd075c 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -36,9 +36,8 @@
*
* If you need less than 50 threads would mean we're dealing with systems
* smaller than 3200 pages. This assumes you are capable of having ~13M memory,
- * and this would only be an be an upper limit, after which the OOM killer
- * would take effect. Systems like these are very unlikely if modules are
- * enabled.
+ * and this would only be an upper limit, after which the OOM killer would take
+ * effect. Systems like these are very unlikely if modules are enabled.
*/
#define MAX_KMOD_CONCURRENT 50
static atomic_t kmod_concurrent_max = ATOMIC_INIT(MAX_KMOD_CONCURRENT);
--
2.1.0
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH v4 3/4] kmod: Return directly if module name is empty in request_module()
2020-04-21 7:05 [PATCH v4 0/4] Fix some issues about kmod Tiezhu Yang
2020-04-21 7:05 ` [PATCH v4 1/4] selftests: kmod: Use variable NAME in kmod_test_0001() Tiezhu Yang
2020-04-21 7:05 ` [PATCH v4 2/4] kmod: Remove redundant "be an" in the comment Tiezhu Yang
@ 2020-04-21 7:05 ` Tiezhu Yang
2020-04-22 8:32 ` Luis Chamberlain
2020-04-21 7:05 ` [PATCH v4 4/4] test_kmod: Avoid potential double free in trigger_config_run_type() Tiezhu Yang
2020-05-11 12:59 ` [PATCH v4 0/4] Fix some issues about kmod Tiezhu Yang
4 siblings, 1 reply; 9+ messages in thread
From: Tiezhu Yang @ 2020-04-21 7:05 UTC (permalink / raw)
To: Luis Chamberlain, Shuah Khan, Andrew Morton, Jessica Yu
Cc: linux-kselftest, linux-kernel, Markus Elfring, Xuefeng Li
If module name is empty, it is better to return directly at the beginning
of request_module() without doing the needless call_modprobe() operation.
(1) In the kernel space
Call trace:
request_module()
|
|
__request_module()
|
|
call_modprobe()
|
|
call_usermodehelper_exec() -- retval = sub_info->retval;
|
|
call_usermodehelper_exec_work()
|
|
call_usermodehelper_exec_sync() -- sub_info->retval = ret;
|
| --> call_usermodehelper_exec_async() --> do_execve()
|
kernel_wait4(pid, (int __user *)&ret, 0, NULL);
The exit status of child process is wrote to the address of variable
"ret" after call kernel_wait4(), its value is 256 if module name is
empty, then sub_info->retval is assigned to "ret" which is 256, the
function call_usermodehelper_exec() returns 256, call_modprobe() and
__request_module() also return 256.
(2)In the user space
when build and execute the following application, we can see the exit
status is 256.
$ ./system
exit status = 256
$ ./execl
exit status = 256
$ cat system.c
#include <stdio.h>
#include <stdlib.h>
int main()
{
int status = 0;
status = system("modprobe '' > /dev/null 2>&1");
printf("exit status = %d\n", status);
return status;
}
$ cat execl.c
#include <sys/wait.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
int main()
{
pid_t pid, w;
int status;
pid = fork();
if (pid == -1) {
perror("fork");
exit(EXIT_FAILURE);
}
if (pid == 0) {
execl("/bin/sh", "sh", "-c",
"modprobe '' > /dev/null 2>&1", (char *) 0);
} else {
w = waitpid(pid, &status, 0);
if (w == -1) {
perror("waitpid");
exit(EXIT_FAILURE);
}
printf("exit status = %d\n", status);
exit(EXIT_SUCCESS);
}
return 0;
}
The exit status of child process is wrote to the address of variable
"status" after call waitpid() in the user space that corresponds with
kernel_wait4() in the kernel space.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
v4:
- update the commit message with application
v3:
- no changes
v2:
- update the commit message to explain the detailed reason
kernel/kmod.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 3cd075c..5851444 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -28,6 +28,8 @@
#include <trace/events/module.h>
+#define MODULE_NOT_FOUND 256
+
/*
* Assuming:
*
@@ -144,6 +146,9 @@ int __request_module(bool wait, const char *fmt, ...)
if (ret >= MODULE_NAME_LEN)
return -ENAMETOOLONG;
+ if (strlen(module_name) == 0)
+ return MODULE_NOT_FOUND;
+
ret = security_kernel_module_request(module_name);
if (ret)
return ret;
--
2.1.0
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH v4 3/4] kmod: Return directly if module name is empty in request_module()
2020-04-21 7:05 ` [PATCH v4 3/4] kmod: Return directly if module name is empty in request_module() Tiezhu Yang
@ 2020-04-22 8:32 ` Luis Chamberlain
0 siblings, 0 replies; 9+ messages in thread
From: Luis Chamberlain @ 2020-04-22 8:32 UTC (permalink / raw)
To: Tiezhu Yang
Cc: Shuah Khan, Andrew Morton, Jessica Yu, linux-kselftest,
linux-kernel, Markus Elfring, Xuefeng Li
On Tue, Apr 21, 2020 at 03:05:03PM +0800, Tiezhu Yang wrote:
> The exit status of child process is wrote to the address of variable
> "status" after call waitpid() in the user space that corresponds with
> kernel_wait4() in the kernel space.
NACK, the issue is in umh, I'll send a fix.
Luis
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v4 4/4] test_kmod: Avoid potential double free in trigger_config_run_type()
2020-04-21 7:05 [PATCH v4 0/4] Fix some issues about kmod Tiezhu Yang
` (2 preceding siblings ...)
2020-04-21 7:05 ` [PATCH v4 3/4] kmod: Return directly if module name is empty in request_module() Tiezhu Yang
@ 2020-04-21 7:05 ` Tiezhu Yang
2020-05-11 12:59 ` [PATCH v4 0/4] Fix some issues about kmod Tiezhu Yang
4 siblings, 0 replies; 9+ messages in thread
From: Tiezhu Yang @ 2020-04-21 7:05 UTC (permalink / raw)
To: Luis Chamberlain, Shuah Khan, Andrew Morton, Jessica Yu
Cc: linux-kselftest, linux-kernel, Markus Elfring, Xuefeng Li
Reset the member "test_fs" of the test configuration after a call
of the function "kfree_const" to a null pointer so that a double
memory release will not be performed.
Fixes: d9c6a72d6fa2 ("kmod: add test driver to stress test the module loader")
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
v4:
- no changes
v3:
- use the quotes with correct format in the commit message,
sorry for that
v2:
- update the commit message suggested by Markus Elfring
- add the Fixes tag
lib/test_kmod.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/test_kmod.c b/lib/test_kmod.c
index e651c37..eab5277 100644
--- a/lib/test_kmod.c
+++ b/lib/test_kmod.c
@@ -745,7 +745,7 @@ static int trigger_config_run_type(struct kmod_test_device *test_dev,
break;
case TEST_KMOD_FS_TYPE:
kfree_const(config->test_fs);
- config->test_driver = NULL;
+ config->test_fs = NULL;
copied = config_copy_test_fs(config, test_str,
strlen(test_str));
break;
--
2.1.0
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH v4 0/4] Fix some issues about kmod
2020-04-21 7:05 [PATCH v4 0/4] Fix some issues about kmod Tiezhu Yang
` (3 preceding siblings ...)
2020-04-21 7:05 ` [PATCH v4 4/4] test_kmod: Avoid potential double free in trigger_config_run_type() Tiezhu Yang
@ 2020-05-11 12:59 ` Tiezhu Yang
2020-05-11 18:28 ` Luis Chamberlain
4 siblings, 1 reply; 9+ messages in thread
From: Tiezhu Yang @ 2020-05-11 12:59 UTC (permalink / raw)
To: akpm, jeyu, mcgrof, shuah
Cc: yangtiezhu, Markus.Elfring, linux-kernel, linux-kselftest, lixuefeng
Hi,
Could you please apply the following three patches?
[v4,1/4] selftests: kmod: Use variable NAME in kmod_test_0001()
https://lore.kernel.org/patchwork/patch/1227980/
[v4,2/4] kmod: Remove redundant "be an" in the comment
https://lore.kernel.org/patchwork/patch/1227982/
[v4,4/4] test_kmod: Avoid potential double free in trigger_config_run_type()
https://lore.kernel.org/patchwork/patch/1227978/
Thanks,
Tiezhu Yang
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v4 0/4] Fix some issues about kmod
2020-05-11 12:59 ` [PATCH v4 0/4] Fix some issues about kmod Tiezhu Yang
@ 2020-05-11 18:28 ` Luis Chamberlain
2020-06-10 2:33 ` Luis Chamberlain
0 siblings, 1 reply; 9+ messages in thread
From: Luis Chamberlain @ 2020-05-11 18:28 UTC (permalink / raw)
To: Tiezhu Yang
Cc: akpm, jeyu, shuah, Markus.Elfring, linux-kernel, linux-kselftest,
lixuefeng
On Mon, May 11, 2020 at 08:59:37PM +0800, Tiezhu Yang wrote:
> Hi,
>
> Could you please apply the following three patches?
>
> [v4,1/4] selftests: kmod: Use variable NAME in kmod_test_0001()
> https://lore.kernel.org/patchwork/patch/1227980/
>
> [v4,2/4] kmod: Remove redundant "be an" in the comment
> https://lore.kernel.org/patchwork/patch/1227982/
>
> [v4,4/4] test_kmod: Avoid potential double free in trigger_config_run_type()
> https://lore.kernel.org/patchwork/patch/1227978/
Andrew,
These 3 patches should be fine.
I am re-working a replacement proper fix for patch #3, that requires a
change to the umh. I'll try to iron this out today.
Luis
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v4 0/4] Fix some issues about kmod
2020-05-11 18:28 ` Luis Chamberlain
@ 2020-06-10 2:33 ` Luis Chamberlain
0 siblings, 0 replies; 9+ messages in thread
From: Luis Chamberlain @ 2020-06-10 2:33 UTC (permalink / raw)
To: Tiezhu Yang
Cc: Andrew Morton, Jessica Yu, Shuah Khan, Markus Elfring,
linux-kernel, open list:KERNEL SELFTEST FRAMEWORK, Xuefeng Li
On Mon, May 11, 2020 at 12:28 PM Luis Chamberlain <mcgrof@kernel.org> wrote:
>
> On Mon, May 11, 2020 at 08:59:37PM +0800, Tiezhu Yang wrote:
> > Hi,
> >
> > Could you please apply the following three patches?
> >
> > [v4,1/4] selftests: kmod: Use variable NAME in kmod_test_0001()
> > https://lore.kernel.org/patchwork/patch/1227980/
> >
> > [v4,2/4] kmod: Remove redundant "be an" in the comment
> > https://lore.kernel.org/patchwork/patch/1227982/
> >
> > [v4,4/4] test_kmod: Avoid potential double free in trigger_config_run_type()
> > https://lore.kernel.org/patchwork/patch/1227978/
>
> Andrew,
>
> These 3 patches should be fine.
>
> I am re-working a replacement proper fix for patch #3, that requires a
> change to the umh. I'll try to iron this out today.
I'll pick these up, and run tests now that I have a finalized solution
in place for the patch replacement I mentioned which was needed. Sorry
this took so long, but I am glad I took my time. I'll post soon after
I test the new fix.
Luis
^ permalink raw reply [flat|nested] 9+ messages in thread