Hi,
On 28/04/23 11:29 am, Harshit Mogalapalli wrote:
Smatch warns:
kernel/module/stats.c:394 read_file_mod_stats()
warn: passing freed memory 'buf'
We are passing 'buf' to simple_read_from_buffer() after freeing it.
Fix this by changing the order of 'simple_read_from_buffer' and 'kfree'.
Friendly reminder to review this patch.
Thanks,
Harshit
Fixes: df3e764d8e5c ("module: add debug stats to help identify memory pressure")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx>
---
Found with statis analysis, only compile tested.
---
kernel/module/stats.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/module/stats.c b/kernel/module/stats.c
index ad7b6ada29f2..6ab2c94d6bc3 100644
--- a/kernel/module/stats.c
+++ b/kernel/module/stats.c
@@ -276,6 +276,7 @@ static ssize_t read_file_mod_stats(struct file *file, char __user *user_buf,
struct mod_fail_load *mod_fail;
unsigned int len, size, count_failed = 0;
char *buf;
+ int ret;
u32 live_mod_count, fkreads, fdecompress, fbecoming, floads;
unsigned long total_size, text_size, ikread_bytes, ibecoming_bytes,
idecompress_bytes, imod_bytes, total_virtual_lost;
@@ -390,8 +391,9 @@ static ssize_t read_file_mod_stats(struct file *file, char __user *user_buf,
out_unlock:
mutex_unlock(&module_mutex);
out:
+ ret = simple_read_from_buffer(user_buf, count, ppos, buf, len);
kfree(buf);
- return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+ return ret;
}
#undef MAX_PREAMBLE
#undef MAX_FAILED_MOD_PRINT
