From ba9a32b176c31ec4d3d7314bb2e529a85423f7a4 Mon Sep 17 00:00:00 2001 From: Joel Stanley Date: Thu, 24 Apr 2014 16:55:33 +0930 Subject: [PATCH] powerpc/powernv: Fix sysparam sysfs error handling When a sysparam query in OPAL returned a negative value (error code), sysfs would spew out a decent chunk of memory; almost 64K more than expected. This was traced to a sign/unsigned mix up in the OPAL sysparam sysfs code at sys_param_show. The return value of sys_param_show is a ssize_t, calculated using return ret ? ret : attr->param_size; Alan Modra explains: "attr->param_size" is an unsigned int, "ret" an int, so the overall expression has type unsigned int. Result is that ret is cast to unsigned int before being cast to ssize_t. Instead of using the ternary operator, set ret to the param_size if an error is not detected. The same bug exists in the sysfs write callback; this patch fixes it in the same way. A note on debugging this next time: on my system gcc will warn about this if compiled with -Wsign-compare, which is not enabled by -Wall, only -Wextra. Signed-off-by: Joel Stanley Signed-off-by: Benjamin Herrenschmidt --- Reading git-format-patch failed