3 Commits

Author	SHA1	Message	Date
Masami Hiramatsu (Google)	c0f3bb4054	rethook: Reject getting a rethook if RCU is not watching ... 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) <mhiramat@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/bpf/165461827269.280167.7379263615545598958.stgit@devnote2	2022-06-17 21:53:35 +02:00
Masami Hiramatsu	a2fb49833c	rethook: Fix to use WRITE_ONCE() for rethook:: Handler ... 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 <alexei.starovoitov@gmail.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/164868907688.21983.1606862921419988152.stgit@devnote2	2022-03-30 19:28:17 -07:00
Masami Hiramatsu	54ecbe6f1e	rethook: Add a generic return hook ... 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 <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/164735285066.1084943.9259661137330166643.stgit@devnote2	2022-03-17 20:16:29 -07:00