kprobes: Fix random address output of blacklist file

File /sys/kernel/debug/kprobes/blacklist displays random addresses:

[root@s8360046 linux]# cat /sys/kernel/debug/kprobes/blacklist
0x0000000047149a90-0x00000000bfcb099a	print_type_x8
....

This breaks 'perf probe' which uses the blacklist file to prohibit
probes on certain functions by checking the address range.

Fix this by printing the correct (unhashed) address.

The file mode is read all but this is not an issue as the file
hierarchy points out:
 # ls -ld /sys/ /sys/kernel/ /sys/kernel/debug/ /sys/kernel/debug/kprobes/
	/sys/kernel/debug/kprobes/blacklist
dr-xr-xr-x 12 root root 0 Apr 19 07:56 /sys/
drwxr-xr-x  8 root root 0 Apr 19 07:56 /sys/kernel/
drwx------ 16 root root 0 Apr 19 06:56 /sys/kernel/debug/
drwxr-xr-x  2 root root 0 Apr 19 06:56 /sys/kernel/debug/kprobes/
-r--r--r--  1 root root 0 Apr 19 06:56 /sys/kernel/debug/kprobes/blacklist

Everything in and below /sys/kernel/debug is rwx to root only,
no group or others have access.

Background:
Directory /sys/kernel/debug/kprobes is created by debugfs_create_dir()
which sets the mode bits to rwxr-xr-x. Maybe change that to use the
parent's directory mode bits instead?

Link: http://lkml.kernel.org/r/20180419105556.86664-1-tmricht@linux.ibm.com
Fixes: ad67b74d2469 ("printk: hash addresses printed with %p")
Cc: stable@vger.kernel.org
Cc: <stable@vger.kernel.org> # v4.15+
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S Miller <davem@davemloft.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: acme@kernel.org
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 102160ff5c661e475e773888bfc3267d832bd4d6..ea619021d9011dca88f0aa10e3263f7dc2177394 100644 (file)
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2428,7 +2428,7 @@ static int kprobe_blacklist_seq_show(struct seq_file *m, void *v)
        struct kprobe_blacklist_entry *ent =
                list_entry(v, struct kprobe_blacklist_entry, list);
 
-       seq_printf(m, "0x%p-0x%p\t%ps\n", (void *)ent->start_addr,
+       seq_printf(m, "0x%px-0x%px\t%ps\n", (void *)ent->start_addr,
                   (void *)ent->end_addr, (void *)ent->start_addr);
        return 0;
 }