From: Ran Xiaokai <ran.xiaokai@zte.com.cn>
This is a preparation patch, when converted to rcu lock,
set_report_filterlist_whitelist() may fail due to memory alloction,
refactor it to return a value, so the error codes can be
passed to the userspace.
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
---
kernel/kcsan/debugfs.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
diff --git a/kernel/kcsan/debugfs.c b/kernel/kcsan/debugfs.c
index ed483987869e..30547507f497 100644
--- a/kernel/kcsan/debugfs.c
+++ b/kernel/kcsan/debugfs.c
@@ -131,13 +131,14 @@ bool kcsan_skip_report_debugfs(unsigned long func_addr)
return ret;
}
-static void set_report_filterlist_whitelist(bool whitelist)
+static ssize_t set_report_filterlist_whitelist(bool whitelist)
{
unsigned long flags;
spin_lock_irqsave(&report_filterlist_lock, flags);
report_filterlist.whitelist = whitelist;
spin_unlock_irqrestore(&report_filterlist_lock, flags);
+ return 0;
}
/* Returns 0 on success, error-code otherwise. */
@@ -225,6 +226,7 @@ debugfs_write(struct file *file, const char __user *buf, size_t count, loff_t *o
char kbuf[KSYM_NAME_LEN];
char *arg;
const size_t read_len = min(count, sizeof(kbuf) - 1);
+ ssize_t ret;
if (copy_from_user(kbuf, buf, read_len))
return -EFAULT;
@@ -242,19 +244,19 @@ debugfs_write(struct file *file, const char __user *buf, size_t count, loff_t *o
return -EINVAL;
microbenchmark(iters);
} else if (!strcmp(arg, "whitelist")) {
- set_report_filterlist_whitelist(true);
+ ret = set_report_filterlist_whitelist(true);
} else if (!strcmp(arg, "blacklist")) {
- set_report_filterlist_whitelist(false);
+ ret = set_report_filterlist_whitelist(false);
} else if (arg[0] == '!') {
- ssize_t ret = insert_report_filterlist(&arg[1]);
-
- if (ret < 0)
- return ret;
+ ret = insert_report_filterlist(&arg[1]);
} else {
return -EINVAL;
}
- return count;
+ if (ret < 0)
+ return ret;
+ else
+ return count;
}
static const struct file_operations debugfs_ops =
--
2.15.2On Wed, 25 Sept 2024 at 16:32, ran xiaokai <ranxiaokai627@163.com> wrote:
>
> From: Ran Xiaokai <ran.xiaokai@zte.com.cn>
>
> This is a preparation patch, when converted to rcu lock,
> set_report_filterlist_whitelist() may fail due to memory alloction,
> refactor it to return a value, so the error codes can be
> passed to the userspace.
>
> Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
> ---
> kernel/kcsan/debugfs.c | 18 ++++++++++--------
> 1 file changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/kernel/kcsan/debugfs.c b/kernel/kcsan/debugfs.c
> index ed483987869e..30547507f497 100644
> --- a/kernel/kcsan/debugfs.c
> +++ b/kernel/kcsan/debugfs.c
> @@ -131,13 +131,14 @@ bool kcsan_skip_report_debugfs(unsigned long func_addr)
> return ret;
> }
>
> -static void set_report_filterlist_whitelist(bool whitelist)
> +static ssize_t set_report_filterlist_whitelist(bool whitelist)
> {
> unsigned long flags;
>
> spin_lock_irqsave(&report_filterlist_lock, flags);
> report_filterlist.whitelist = whitelist;
> spin_unlock_irqrestore(&report_filterlist_lock, flags);
> + return 0;
> }
>
> /* Returns 0 on success, error-code otherwise. */
> @@ -225,6 +226,7 @@ debugfs_write(struct file *file, const char __user *buf, size_t count, loff_t *o
> char kbuf[KSYM_NAME_LEN];
> char *arg;
> const size_t read_len = min(count, sizeof(kbuf) - 1);
> + ssize_t ret;
This may be uninitialized depending on the branch taken below.
> if (copy_from_user(kbuf, buf, read_len))
> return -EFAULT;
> @@ -242,19 +244,19 @@ debugfs_write(struct file *file, const char __user *buf, size_t count, loff_t *o
> return -EINVAL;
> microbenchmark(iters);
> } else if (!strcmp(arg, "whitelist")) {
> - set_report_filterlist_whitelist(true);
> + ret = set_report_filterlist_whitelist(true);
> } else if (!strcmp(arg, "blacklist")) {
> - set_report_filterlist_whitelist(false);
> + ret = set_report_filterlist_whitelist(false);
> } else if (arg[0] == '!') {
> - ssize_t ret = insert_report_filterlist(&arg[1]);
> -
> - if (ret < 0)
> - return ret;
> + ret = insert_report_filterlist(&arg[1]);
> } else {
> return -EINVAL;
> }
>
> - return count;
> + if (ret < 0)
> + return ret;
> + else
> + return count;
> }
>
> static const struct file_operations debugfs_ops =
> --
> 2.15.2
>
Hi ran,
kernel test robot noticed the following build warnings:
[auto build test WARNING on linus/master]
[also build test WARNING on next-20240925]
[cannot apply to v6.11]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/ran-xiaokai/kcsan-debugfs-Remove-redundant-call-of-kallsyms_lookup_name/20240925-231034
base: linus/master
patch link: https://lore.kernel.org/r/20240925143154.2322926-3-ranxiaokai627%40163.com
patch subject: [PATCH 2/4] kcsan, debugfs: refactor set_report_filterlist_whitelist() to return a value
config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20240926/202409261331.9NyGRPt2-lkp@intel.com/config)
compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240926/202409261331.9NyGRPt2-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202409261331.9NyGRPt2-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> kernel/kcsan/debugfs.c:243:7: warning: variable 'ret' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
243 | if (kstrtoul(&arg[strlen("microbench=")], 0, &iters))
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
kernel/kcsan/debugfs.c:256:6: note: uninitialized use occurs here
256 | if (ret < 0)
| ^~~
kernel/kcsan/debugfs.c:243:3: note: remove the 'if' if its condition is always true
243 | if (kstrtoul(&arg[strlen("microbench=")], 0, &iters))
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
244 | return -EINVAL;
>> kernel/kcsan/debugfs.c:238:13: warning: variable 'ret' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
238 | } else if (!strcmp(arg, "off")) {
| ^~~~~~~~~~~~~~~~~~~
kernel/kcsan/debugfs.c:256:6: note: uninitialized use occurs here
256 | if (ret < 0)
| ^~~
kernel/kcsan/debugfs.c:238:9: note: remove the 'if' if its condition is always false
238 | } else if (!strcmp(arg, "off")) {
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
239 | WRITE_ONCE(kcsan_enabled, false);
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
240 | } else if (str_has_prefix(arg, "microbench=")) {
| ~~~~~~
kernel/kcsan/debugfs.c:236:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
236 | if (!strcmp(arg, "on")) {
| ^~~~~~~~~~~~~~~~~~
kernel/kcsan/debugfs.c:256:6: note: uninitialized use occurs here
256 | if (ret < 0)
| ^~~
kernel/kcsan/debugfs.c:236:2: note: remove the 'if' if its condition is always false
236 | if (!strcmp(arg, "on")) {
| ^~~~~~~~~~~~~~~~~~~~~~~~~
237 | WRITE_ONCE(kcsan_enabled, true);
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
238 | } else if (!strcmp(arg, "off")) {
| ~~~~~~
kernel/kcsan/debugfs.c:229:13: note: initialize the variable 'ret' to silence this warning
229 | ssize_t ret;
| ^
| = 0
3 warnings generated.
vim +243 kernel/kcsan/debugfs.c
dfd402a4c4baae Marco Elver 2019-11-14 222
5cbaefe9743bf1 Ingo Molnar 2019-11-20 223 static ssize_t
5cbaefe9743bf1 Ingo Molnar 2019-11-20 224 debugfs_write(struct file *file, const char __user *buf, size_t count, loff_t *off)
dfd402a4c4baae Marco Elver 2019-11-14 225 {
dfd402a4c4baae Marco Elver 2019-11-14 226 char kbuf[KSYM_NAME_LEN];
dfd402a4c4baae Marco Elver 2019-11-14 227 char *arg;
43d631bf06ec96 Thorsten Blum 2024-06-24 228 const size_t read_len = min(count, sizeof(kbuf) - 1);
52313281c8b7ca Ran Xiaokai 2024-09-25 229 ssize_t ret;
dfd402a4c4baae Marco Elver 2019-11-14 230
dfd402a4c4baae Marco Elver 2019-11-14 231 if (copy_from_user(kbuf, buf, read_len))
dfd402a4c4baae Marco Elver 2019-11-14 232 return -EFAULT;
dfd402a4c4baae Marco Elver 2019-11-14 233 kbuf[read_len] = '\0';
dfd402a4c4baae Marco Elver 2019-11-14 234 arg = strstrip(kbuf);
dfd402a4c4baae Marco Elver 2019-11-14 235
dfd402a4c4baae Marco Elver 2019-11-14 236 if (!strcmp(arg, "on")) {
dfd402a4c4baae Marco Elver 2019-11-14 237 WRITE_ONCE(kcsan_enabled, true);
dfd402a4c4baae Marco Elver 2019-11-14 @238 } else if (!strcmp(arg, "off")) {
dfd402a4c4baae Marco Elver 2019-11-14 239 WRITE_ONCE(kcsan_enabled, false);
a4e74fa5f0d3e2 Marco Elver 2020-07-31 240 } else if (str_has_prefix(arg, "microbench=")) {
dfd402a4c4baae Marco Elver 2019-11-14 241 unsigned long iters;
dfd402a4c4baae Marco Elver 2019-11-14 242
a4e74fa5f0d3e2 Marco Elver 2020-07-31 @243 if (kstrtoul(&arg[strlen("microbench=")], 0, &iters))
dfd402a4c4baae Marco Elver 2019-11-14 244 return -EINVAL;
dfd402a4c4baae Marco Elver 2019-11-14 245 microbenchmark(iters);
dfd402a4c4baae Marco Elver 2019-11-14 246 } else if (!strcmp(arg, "whitelist")) {
52313281c8b7ca Ran Xiaokai 2024-09-25 247 ret = set_report_filterlist_whitelist(true);
dfd402a4c4baae Marco Elver 2019-11-14 248 } else if (!strcmp(arg, "blacklist")) {
52313281c8b7ca Ran Xiaokai 2024-09-25 249 ret = set_report_filterlist_whitelist(false);
dfd402a4c4baae Marco Elver 2019-11-14 250 } else if (arg[0] == '!') {
52313281c8b7ca Ran Xiaokai 2024-09-25 251 ret = insert_report_filterlist(&arg[1]);
dfd402a4c4baae Marco Elver 2019-11-14 252 } else {
dfd402a4c4baae Marco Elver 2019-11-14 253 return -EINVAL;
dfd402a4c4baae Marco Elver 2019-11-14 254 }
dfd402a4c4baae Marco Elver 2019-11-14 255
52313281c8b7ca Ran Xiaokai 2024-09-25 256 if (ret < 0)
52313281c8b7ca Ran Xiaokai 2024-09-25 257 return ret;
52313281c8b7ca Ran Xiaokai 2024-09-25 258 else
dfd402a4c4baae Marco Elver 2019-11-14 259 return count;
dfd402a4c4baae Marco Elver 2019-11-14 260 }
dfd402a4c4baae Marco Elver 2019-11-14 261
--
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