From 999b8b88c6060adf7a9b7907740ae86ace65291e Mon Sep 17 00:00:00 2001 From: Vincent Bernat Date: Sat, 15 Aug 2015 15:49:13 +0200 Subject: [PATCH] 9p: ensure err is initialized to 0 in p9_client_read/write Some use of those functions were providing unitialized values to those functions. Notably, when reading 0 bytes from an empty file on a 9P filesystem, the return code of read() was not 0. Tested with this simple program: #include #include #include #include #include int main(int argc, const char **argv) { assert(argc == 2); char buffer[256]; int fd = open(argv[1], O_RDONLY|O_NOCTTY); assert(fd >= 0); assert(read(fd, buffer, 0) == 0); return 0; } Cc: stable@vger.kernel.org # v4.1 Signed-off-by: Vincent Bernat Signed-off-by: Al Viro --- net/9p/client.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/9p/client.c b/net/9p/client.c index 498454b3c06c..ea79ee9a7348 100644 --- a/net/9p/client.c +++ b/net/9p/client.c @@ -1541,6 +1541,7 @@ p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err) struct p9_client *clnt = fid->clnt; struct p9_req_t *req; int total = 0; + *err = 0; p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n", fid->fid, (unsigned long long) offset, (int)iov_iter_count(to)); @@ -1620,6 +1621,7 @@ p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err) struct p9_client *clnt = fid->clnt; struct p9_req_t *req; int total = 0; + *err = 0; p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n", fid->fid, (unsigned long long) offset,