kernel.git/kernel/trace/rethook.c, branch linux-5.18.y

rethook: Reject getting a rethook if RCU is not watching

2022-06-29T07:04:30Z

[ Upstream commit c0f3bb4054ef036e5f67e27f2e3cad9e6512cf00 ] Since the rethook_recycle() will involve the call_rcu() for reclaiming the rethook_instance, the rethook must be set up at the RCU available context (non idle). This rethook_recycle() in the rethook trampoline handler is inevitable, thus the RCU available check must be done before setting the rethook trampoline. This adds a rcu_is_watching() check in the rethook_try_get() so that it will return NULL if it is called when !rcu_is_watching(). Fixes: 54ecbe6f1ed5 ("rethook: Add a generic return hook") Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Daniel Borkmann Acked-by: Steven Rostedt (Google) Acked-by: Jiri Olsa Link: https://lore.kernel.org/bpf/165461827269.280167.7379263615545598958.stgit@devnote2 Signed-off-by: Sasha Levin

rethook: Fix to use WRITE_ONCE() for rethook:: Handler

2022-03-31T02:28:17Z

Since the function pointered by rethook::handler never be removed when the rethook is alive, it doesn't need to use rcu_assign_pointer() to update it. Just use WRITE_ONCE(). Reported-by: Alexei Starovoitov Signed-off-by: Masami Hiramatsu Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/164868907688.21983.1606862921419988152.stgit@devnote2

rethook: Add a generic return hook

2022-03-18T03:16:29Z

Add a return hook framework which hooks the function return. Most of the logic came from the kretprobe, but this is independent from kretprobe. Note that this is expected to be used with other function entry hooking feature, like ftrace, fprobe, adn kprobes. Eventually this will replace the kretprobe (e.g. kprobe + rethook = kretprobe), but at this moment, this is just an additional hook. Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (Google) Tested-by: Steven Rostedt (Google) Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/164735285066.1084943.9259661137330166643.stgit@devnote2