4.16-stable review patch. If anyone has any objections, please let me know.
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From: Thomas Richter tmricht@linux.ibm.com
commit bcbd385b61bbdef3491d662203ac2e8186e5be59 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- kernel/kprobes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2428,7 +2428,7 @@ static int kprobe_blacklist_seq_show(str 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; }