From 27a2c36c9538c7e5536a1b20fd74f0fc911d7950 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 8 May 2024 05:43:39 +0200 Subject: Merging upstream version 4.19.269. Signed-off-by: Daniel Baumann --- kernel/livepatch/transition.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) (limited to 'kernel/livepatch/transition.c') diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c index 5bc349805..20277ad6b 100644 --- a/kernel/livepatch/transition.c +++ b/kernel/livepatch/transition.c @@ -563,9 +563,23 @@ void klp_reverse_transition(void) /* Called from copy_process() during fork */ void klp_copy_process(struct task_struct *child) { - child->patch_state = current->patch_state; - /* TIF_PATCH_PENDING gets copied in setup_thread_stack() */ + /* + * The parent process may have gone through a KLP transition since + * the thread flag was copied in setup_thread_stack earlier. Bring + * the task flag up to date with the parent here. + * + * The operation is serialized against all klp_*_transition() + * operations by the tasklist_lock. The only exception is + * klp_update_patch_state(current), but we cannot race with + * that because we are current. + */ + if (test_tsk_thread_flag(current, TIF_PATCH_PENDING)) + set_tsk_thread_flag(child, TIF_PATCH_PENDING); + else + clear_tsk_thread_flag(child, TIF_PATCH_PENDING); + + child->patch_state = current->patch_state; } /* -- cgit v1.2.3