The following commit has been merged into the x86/core branch of tip:
Commit-ID: c841668784cc609e7ae103d91c3e03bf8939418d
Gitweb: https://git.kernel.org/tip/c841668784cc609e7ae103d91c3e03bf8939418d
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Fri, 11 Mar 2022 10:40:40 +01:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Fri, 11 Mar 2022 13:05:08 +01:00
x86,ftrace: Fix modify_ftrace_direct()
Alexei reported that BPF direct trampolines are no longer working with
IBT=y builds.
Make modify_ftrace_direct() consistent vs
{,un}register_ftrace_direct(), such that they all agree on where the
__fentry__ site lives.
Fixes: ee1a8cf8dd0f ("x86/ibt,ftrace: Search for __fentry__ location")
Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/YioBZmicMj7aAlLf@hirez.programming.kicks-ass.net
---
kernel/trace/ftrace.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index ae0d9f6..8e0509e 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5381,6 +5381,11 @@ int modify_ftrace_direct(unsigned long ip,
mutex_lock(&direct_mutex);
mutex_lock(&ftrace_lock);
+
+ ip = ftrace_location(ip);
+ if (!ip)
+ goto out_unlock;
+
entry = find_direct_entry(&ip, &rec);
if (!entry)
goto out_unlock;