Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: - [Low] trace/fgraph: mixed goto-based error handling with scope-based cleanup --
commit 6422a16035934ad7c858389b51cb5a7d9fecc15f Author: Ye Liu <[email protected]> tracing/fgraph: convert process/thread iterator to for_each_process_thread_rculock This commit converts the manual rcu_read_lock() and rcu_read_unlock() pair around the for_each_process_thread() loop in alloc_retstack_tasklist() to use the for_each_process_thread_rculock() macro. This scopes the RCU read lock to the loop body using a scoped guard, and removes the manual unlock label in the error handling path. > diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c > index 40d373d65f9b9..f797ce1192233 100644 > --- a/kernel/trace/fgraph.c > +++ b/kernel/trace/fgraph.c > @@ -1057,11 +1057,10 @@ static int alloc_retstack_tasklist(unsigned long > **ret_stack_list) > } > } > > - rcu_read_lock(); > - for_each_process_thread(g, t) { > + for_each_process_thread_rculock(g, t) { > if (start == end) { > ret = -EAGAIN; > - goto unlock; > + goto free; [Severity: Low] This doesn't cause a direct runtime bug here, but does this change mix goto-based cleanup with scope-based cleanup? The for_each_process_thread_rculock() macro initializes a scope-based RCU guard via scoped_guard(rcu). By using goto free; to jump out of the scoped guard to a manual cleanup label, this explicitly violates the strict kernel cleanup rule in include/linux/cleanup.h meant to prevent double-free and resource leak bugs. That rule states that goto-based cleanup and scope-based cleanup must never be mixed in the same function. While jumping out of scoped_guard() here triggers the RCU unlock safely before executing the manual free label, should alloc_retstack_tasklist() be fully converted to use scope-based cleanup for the ret_stack_list allocations as well, or should it stick to manual RCU locks to avoid mixing paradigms? > } > > if (t->ret_stack == NULL) { [ ... ] > @@ -1074,9 +1073,6 @@ static int alloc_retstack_tasklist(unsigned long > **ret_stack_list) > t->ret_stack = ret_stack_list[start++]; > } > } > - > -unlock: > - rcu_read_unlock(); > free: > for (i = start; i < end; i++) > kmem_cache_free(fgraph_stack_cachep, ret_stack_list[i]); -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=11
