On 04/17/2018 10:20 AM, Thomas Richter wrote:
> In kernel v4.16.0 the module .text address is displayed
> wrong when using /sys/module/*/sections/.text file.
> Commit ef0010a30935 ("vsprintf: don't use 'restricted_pointer()' when
> not restricting")
> is the first bad commit.
>
> Here is the issue, using module qeth_l2 on s390 which is the
> ethernet device driver:
>
> [root@s35lp76 ~]# lsmod
> Module Size Used by
> qeth_l2 94208 1
> ...
>
> [root@s35lp76 ~]# cat /proc/modules | egrep '^qeth_l2'
> qeth_l2 94208 1 - Live 0x000003ff80401000
> ^ This is the correct address in memory
> [root@s35lp76 ~]# cat /sys/module/qeth_l2/sections/.text
> 0x0000000018ea8363 <---- This is a wrong address
> [root@s35lp76 ~]#
>
> This breaks the perf tool which uses this address on s390
> to calculate start of .text section in memory.
>
> Fix this by printing the correct (unhashed) address.
>
> Thanks to Jessica Yu for helping on this.
>
> Suggested-by: Linus Torvalds <torva...@linux-foundation.org>
> Signed-off-by: Thomas Richter <tmri...@linux.ibm.com>
> Cc: Jessica Yu <j...@kernel.org>
CC stable?
> ---
> kernel/module.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/module.c b/kernel/module.c
> index a6e43a5806a1..77ab7211ddef 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -1472,7 +1472,7 @@ static ssize_t module_sect_show(struct module_attribute
> *mattr,
> {
> struct module_sect_attr *sattr =
> container_of(mattr, struct module_sect_attr, mattr);
> - return sprintf(buf, "0x%pK\n", (void *)sattr->address);
> + return sprintf(buf, "%#lx\n", kptr_restrict < 2 ? sattr->address : 0);
> }
>
> static void free_sect_attrs(struct module_sect_attrs *sect_attrs)
>
