6.12-stable review patch. If anyone has any objections, please let me know.
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From: Di Shen di.shen@unisoc.com
[ Upstream commit 4e2e6841ff761cc15a54e8bebcf35d7325ec78a2 ]
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 xuewen.yan@unisoc.com Signed-off-by: Di Shen di.shen@unisoc.com Acked-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/r/20250520054943.5002-1-xuewen.yan@unisoc.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 66075e86b691c..3ec7df7dbeec4 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -3349,7 +3349,9 @@ 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;