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From: Jordan Rome <linux@jordanrome.com>
To: bpf@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <martin.lau@kernel.org>,
	Kernel Team <kernel-team@fb.com>
Subject: [bpf-next v1 1/2] bpf: Fix iter/task tid filtering
Date: Tue, 15 Oct 2024 11:27:06 -0700	[thread overview]
Message-ID: <20241015182707.1746074-1-linux@jordanrome.com> (raw)

In userspace, you can add a tid filter by setting
the "task.tid" field for "bpf_iter_link_info".
However, `get_pid_task` when called for the
`BPF_TASK_ITER_TID` type should have been using
`PIDTYPE_PID` (tid) instead of `PIDTYPE_TGID` (pid).

Fixes: f0d74c4da1f0 ("bpf: Parameterize task iterators.")
Signed-off-by: Jordan Rome <linux@jordanrome.com>
---
 kernel/bpf/task_iter.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
index 02aa9db8d796..5af9e130e500 100644
--- a/kernel/bpf/task_iter.c
+++ b/kernel/bpf/task_iter.c
@@ -99,7 +99,7 @@ static struct task_struct *task_seq_get_next(struct bpf_iter_seq_task_common *co
 		rcu_read_lock();
 		pid = find_pid_ns(common->pid, common->ns);
 		if (pid) {
-			task = get_pid_task(pid, PIDTYPE_TGID);
+			task = get_pid_task(pid, PIDTYPE_PID);
 			*tid = common->pid;
 		}
 		rcu_read_unlock();
--
2.43.5


             reply	other threads:[~2024-10-15 18:33 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-15 18:27 Jordan Rome [this message]
2024-10-15 18:27 ` [bpf-next v1 2/2] bpf: properly test iter/task tid filtering Jordan Rome
2024-10-16 20:08   ` Andrii Nakryiko
2024-10-16 20:09 ` [bpf-next v1 1/2] bpf: Fix " Andrii Nakryiko

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