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| author | Yi Yang <yiyang13@huawei.com> | 2022-05-10 16:05:33 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-06-09 10:23:28 +0200 |
| commit | 4b02493838d9057b1062c55c678b18ffe291b9d7 (patch) | |
| tree | 2365d0eb08ece7bcd4ecf5998c2964ccde90be98 /arch | |
| parent | fd9a5081ee3311a3ceee9f0f3ddbf508e119b580 (diff) | |
| download | linux-stable-4b02493838d9057b1062c55c678b18ffe291b9d7.tar.gz linux-stable-4b02493838d9057b1062c55c678b18ffe291b9d7.tar.bz2 linux-stable-4b02493838d9057b1062c55c678b18ffe291b9d7.zip | |
xtensa/simdisk: fix proc_read_simdisk()
commit b011946d039d66bbc7102137e98cc67e1356aa87 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/xtensa/platforms/iss/simdisk.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/arch/xtensa/platforms/iss/simdisk.c b/arch/xtensa/platforms/iss/simdisk.c index 3cdfa00738e0..edb27649851f 100644 --- a/arch/xtensa/platforms/iss/simdisk.c +++ b/arch/xtensa/platforms/iss/simdisk.c @@ -212,12 +212,18 @@ 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); } |