From: Dan Carpenter <dan.carpenter@oracle.com> stable inclusion from stable-v5.10.138 commit 291cba960bb89a7fa6f138b0dd7da9ef7e1a9034 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I60QFD Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 32ad11127b95236dfc52375f3707853194a7f4b4 upstream. This code tries to store -EFAULT in an unsigned int. The xenbus_file_read() function returns type ssize_t so the negative value is returned as a positive value to the user. This change forces another change to the min() macro. Originally, the min() macro used "unsigned" type which checkpatch complains about. Also unsigned type would break if "len" were not capped at MAX_RW_COUNT. Use size_t for the min(). (No effect on runtime for the min_t() change). Fixes: 2fb3683e7b16 ("xen: Add xenbus device driver") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Link: https://lore.kernel.org/r/YutxJUaUYRG/VLVc@kili Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> Reviewed-by: Wei Li <liwei391@huawei.com> --- drivers/xen/xenbus/xenbus_dev_frontend.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c index 597af455a522..0792fda49a15 100644 --- a/drivers/xen/xenbus/xenbus_dev_frontend.c +++ b/drivers/xen/xenbus/xenbus_dev_frontend.c @@ -128,7 +128,7 @@ static ssize_t xenbus_file_read(struct file *filp, { struct xenbus_file_priv *u = filp->private_data; struct read_buffer *rb; - unsigned i; + ssize_t i; int ret; mutex_lock(&u->reply_mutex); @@ -148,7 +148,7 @@ static ssize_t xenbus_file_read(struct file *filp, rb = list_entry(u->read_buffers.next, struct read_buffer, list); i = 0; while (i < len) { - unsigned sz = min((unsigned)len - i, rb->len - rb->cons); + size_t sz = min_t(size_t, len - i, rb->len - rb->cons); ret = copy_to_user(ubuf + i, &rb->msg[rb->cons], sz); -- 2.20.1