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authorYi Yang <yiyang13@huawei.com>2022-05-10 16:05:33 +0800
committerMax Filippov <jcmvbkbc@gmail.com>2022-05-11 02:15:38 -0700
commitb011946d039d66bbc7102137e98cc67e1356aa87 (patch)
tree187e0f9ca53b97149bc795bf9945320ade1b1572 /arch/xtensa/platforms
parentc6ab42b31fce42c4b7f775752d91db0f2b71c65e (diff)
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xtensa/simdisk: fix proc_read_simdisk()
The commit a69755b18774 ("xtensa simdisk: switch to proc_create_data()") split read operation into two parts, first retrieving the path when it's non-null and second retrieving the trailing '\n'. However when the path is non-null the first simple_read_from_buffer updates ppos, and the second simple_read_from_buffer returns 0 if ppos is greater than 1 (i.e. almost always). As a result reading from that proc file is almost always empty. Fix it by making a temporary copy of the path with the trailing '\n' and using simple_read_from_buffer on that copy. Cc: stable@vger.kernel.org Fixes: a69755b18774 ("xtensa simdisk: switch to proc_create_data()") Signed-off-by: Yi Yang <yiyang13@huawei.com> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Diffstat (limited to 'arch/xtensa/platforms')
-rw-r--r--arch/xtensa/platforms/iss/simdisk.c18
1 files changed, 12 insertions, 6 deletions
diff --git a/arch/xtensa/platforms/iss/simdisk.c b/arch/xtensa/platforms/iss/simdisk.c
index 0f0e0724397f..4255b92fa3eb 100644
--- a/arch/xtensa/platforms/iss/simdisk.c
+++ b/arch/xtensa/platforms/iss/simdisk.c
@@ -211,12 +211,18 @@ static ssize_t proc_read_simdisk(struct file *file, char __user *buf,
struct simdisk *dev = pde_data(file_inode(file));
const char *s = dev->filename;
if (s) {
- ssize_t n = simple_read_from_buffer(buf, size, ppos,
- s, strlen(s));
- if (n < 0)
- return n;
- buf += n;
- size -= n;
+ ssize_t len = strlen(s);
+ char *temp = kmalloc(len + 2, GFP_KERNEL);
+
+ if (!temp)
+ return -ENOMEM;
+
+ len = scnprintf(temp, len + 2, "%s\n", s);
+ len = simple_read_from_buffer(buf, size, ppos,
+ temp, len);
+
+ kfree(temp);
+ return len;
}
return simple_read_from_buffer(buf, size, ppos, "\n", 1);
}