On Tue, 16 Mar 2021 12:58:15 -0700
Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx> wrote:
> From: Alexei Starovoitov <ast@xxxxxxxxxx>
>
> The following sequence of commands:
> register_ftrace_direct(ip, addr1);
> modify_ftrace_direct(ip, addr1, addr2);
> unregister_ftrace_direct(ip, addr2);
> will cause the kernel to warn:
> [ 30.179191] WARNING: CPU: 2 PID: 1961 at kernel/trace/ftrace.c:5223 unregister_ftrace_direct+0x130/0x150
> [ 30.180556] CPU: 2 PID: 1961 Comm: test_progs W O 5.12.0-rc2-00378-g86bc10a0a711-dirty #3246
> [ 30.182453] RIP: 0010:unregister_ftrace_direct+0x130/0x150
>
> When modify_ftrace_direct() changes the addr from old to new it should update
> the addr stored in ftrace_direct_funcs. Otherwise the final
> unregister_ftrace_direct() won't find the address and will cause the splat.
>
> Fixes: 0567d6809182 ("ftrace: Add modify_ftrace_direct()")
> Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
> ---
>
Reviewed-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
-- Steve
