The current check in rethook_find_ret_addr() prevents obtaining a return
address when the target task is marked as running. However, this condition
is both insufficient for safety and unnecessary for its intended purpose.
The check is inherently racy: a task can begin running on another CPU
immediately after task_is_running() returns false, potentially leading to
concurrent modification of rethook data structures while the iteration is
in progress.
Rather than attempting to fix this unreliable check deep in the unwinding
path, remove it entirely. Callers that require consistency are expected
to provide a safe context.
Fixes: 54ecbe6f1ed5 ("rethook: Add a generic return hook")
Signed-off-by: Tengda Wu <[email protected]>
---
v2: Remove the running task check.
v1:
https://lore.kernel.org/all/[email protected]/
kernel/trace/rethook.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/kernel/trace/rethook.c b/kernel/trace/rethook.c
index 5a8bdf88999a..f70f11bc6c91 100644
--- a/kernel/trace/rethook.c
+++ b/kernel/trace/rethook.c
@@ -250,9 +250,6 @@ unsigned long rethook_find_ret_addr(struct task_struct
*tsk, unsigned long frame
if (WARN_ON_ONCE(!cur))
return 0;
- if (tsk != current && task_is_running(tsk))
- return 0;
-
do {
ret = __rethook_find_ret_addr(tsk, cur);
if (!ret)
--
2.34.1
