From 4e2e6841ff761cc15a54e8bebcf35d7325ec78a2 Mon Sep 17 00:00:00 2001 From: Di Shen Date: Tue, 20 May 2025 13:49:43 +0800 Subject: [PATCH] bpf: Revert "bpf: remove unnecessary rcu_read_{lock,unlock}() in multi-uprobe attach logic" This reverts commit 4a8f635a6054. Althought get_pid_task() internally already calls rcu_read_lock() and rcu_read_unlock(), the find_vpid() was not. The documentation for find_vpid() clearly states: "Must be called with the tasklist_lock or rcu_read_lock() held." Add proper rcu_read_lock/unlock() to protect the find_vpid(). Fixes: 4a8f635a6054 ("bpf: remove unnecessary rcu_read_{lock,unlock}() in multi-uprobe attach logic") Reported-by: Xuewen Yan Signed-off-by: Di Shen Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20250520054943.5002-1-xuewen.yan@unisoc.com Signed-off-by: Alexei Starovoitov --- kernel/trace/bpf_trace.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index b0eb721fcfb5..289ff0caa83e 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -3318,7 +3318,9 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr } if (pid) { + rcu_read_lock(); task = get_pid_task(find_vpid(pid), PIDTYPE_TGID); + rcu_read_unlock(); if (!task) { err = -ESRCH; goto error_path_put; -- 2.50.1