Commit fc0ea795f53c ("ftrace: Add symbols for ftrace trampolines")
missed to remove ops from new ftrace_ops_trampoline_list in
ftrace_startup() if ftrace_hash_ipmodify_enable() fails there. It may
lead to BUG if such ops come from a module which may be removed.
Moreover, the trampoline itself is not freed in this case.
Fix it by calling ftrace_trampoline_free() during the rollback.
Fixes: fc0ea795f53c ("ftrace: Add symbols for ftrace trampolines")
Signed-off-by: Miroslav Benes <[email protected]>
---
It would be fair to add
Fixes: f8b8be8a310a ("ftrace, kprobes: Support IPMODIFY flag to find IP modify conflict")
too. The situation was a bit more complicated back then though since
RCU-tasks support was missing.
kernel/trace/ftrace.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 275441254bb5..656d7cb5a78c 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2862,6 +2862,8 @@ int ftrace_startup(struct ftrace_ops *ops, int command)
__unregister_ftrace_function(ops);
ftrace_start_up--;
ops->flags &= ~FTRACE_OPS_FL_ENABLED;
+ if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
+ ftrace_trampoline_free(ops);
return ret;
}
--
2.28.0
I used Masami's address which did not work. Sorry about that. Should be ok
now.
On Mon, 31 Aug 2020, Miroslav Benes wrote:
> Commit fc0ea795f53c ("ftrace: Add symbols for ftrace trampolines")
> missed to remove ops from new ftrace_ops_trampoline_list in
> ftrace_startup() if ftrace_hash_ipmodify_enable() fails there. It may
> lead to BUG if such ops come from a module which may be removed.
>
> Moreover, the trampoline itself is not freed in this case.
>
> Fix it by calling ftrace_trampoline_free() during the rollback.
>
> Fixes: fc0ea795f53c ("ftrace: Add symbols for ftrace trampolines")
> Signed-off-by: Miroslav Benes <[email protected]>
> ---
>
> It would be fair to add
>
> Fixes: f8b8be8a310a ("ftrace, kprobes: Support IPMODIFY flag to find IP modify conflict")
>
> too. The situation was a bit more complicated back then though since
> RCU-tasks support was missing.
>
> kernel/trace/ftrace.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index 275441254bb5..656d7cb5a78c 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -2862,6 +2862,8 @@ int ftrace_startup(struct ftrace_ops *ops, int command)
> __unregister_ftrace_function(ops);
> ftrace_start_up--;
> ops->flags &= ~FTRACE_OPS_FL_ENABLED;
> + if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
> + ftrace_trampoline_free(ops);
> return ret;
> }
>
> --
> 2.28.0
>
On Mon, 31 Aug 2020 14:56:57 +0200 (CEST)
Miroslav Benes <[email protected]> wrote:
> I used Masami's address which did not work. Sorry about that. Should be ok
> now.
Thanks Miroslav,
I've queued this up to be tested and pushed as urgent.
-- Steve
>
> On Mon, 31 Aug 2020, Miroslav Benes wrote:
>
> > Commit fc0ea795f53c ("ftrace: Add symbols for ftrace trampolines")
> > missed to remove ops from new ftrace_ops_trampoline_list in
> > ftrace_startup() if ftrace_hash_ipmodify_enable() fails there. It may
> > lead to BUG if such ops come from a module which may be removed.
> >
> > Moreover, the trampoline itself is not freed in this case.
> >
> > Fix it by calling ftrace_trampoline_free() during the rollback.
> >
> > Fixes: fc0ea795f53c ("ftrace: Add symbols for ftrace trampolines")
> > Signed-off-by: Miroslav Benes <[email protected]>
> > ---
> >