From: Jiri Olsa <olsajiri@gmail.com>
To: sashiko-reviews@lists.linux.dev
Cc: bpf@vger.kernel.org
Subject: Re: [PATCHv7 bpf-next 01/29] ftrace: Add ftrace_hash_count function
Date: Thu, 4 Jun 2026 09:59:15 +0200 [thread overview]
Message-ID: <aiEwU0CyceOkPrfV@krava> (raw)
In-Reply-To: <20260603112630.3D1EB1F00893@smtp.kernel.org>
On Wed, Jun 03, 2026 at 11:26:29AM +0000, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] The generic ftrace_hash_count() API is incorrectly guarded by CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS, returning a false 0 when direct calls are disabled.
> --
>
> commit 61129b2eed8ea43ed2c045ef25d031a4504c8af4
> Author: Jiri Olsa <jolsa@kernel.org>
>
> ftrace: Add ftrace_hash_count function
>
> Adds an external ftrace_hash_count function to allow retrieving the hash
> count from outside the ftrace object.
>
> > diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
> > index 28b30c6f10314..02c24bf766ced 100644
> > --- a/include/linux/ftrace.h
> > +++ b/include/linux/ftrace.h
> [ ... ]
> > @@ -551,6 +551,8 @@ int update_ftrace_direct_mod(struct ftrace_ops *ops, struct ftrace_hash *hash, b
> >
> > void ftrace_stub_direct_tramp(void);
> >
> > +unsigned long ftrace_hash_count(struct ftrace_hash *hash);
> > +
> > #else
> > struct ftrace_ops;
> > static inline unsigned long ftrace_find_rec_direct(unsigned long ip)
> > @@ -590,6 +592,11 @@ static inline int update_ftrace_direct_mod(struct ftrace_ops *ops, struct ftrace
> > return -ENODEV;
> > }
> >
> > +static inline unsigned long ftrace_hash_count(struct ftrace_hash *hash)
> > +{
> > + return 0;
> > +}
> > +
>
> [Severity: Medium]
> Is it intended to restrict this generic API to configurations where direct
> calls are enabled?
>
> It appears this declaration and the inline dummy are placed inside the
> CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS block.
ftrace_hash_count declaration is in CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
black, the inline stub is in !CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS block
>
> When CONFIG_DYNAMIC_FTRACE is enabled but direct calls are disabled, any
> external caller will silently receive 0. Could this cause subtle logic
> errors for users of this generic ftrace infrastructure?
ftrace_hash_count is enabled for CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
as are all its users, seems ok to me
jirka
>
> > /*
> > * This must be implemented by the architecture.
> > * It is the way the ftrace direct_ops helper, when called
> > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> > index b2611de3f5943..57ab01fd00bda 100644
> > --- a/kernel/trace/ftrace.c
> > +++ b/kernel/trace/ftrace.c
> [ ... ]
> > @@ -6288,11 +6288,16 @@ int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
> > }
> > EXPORT_SYMBOL_GPL(modify_ftrace_direct);
> >
> > -static unsigned long hash_count(struct ftrace_hash *hash)
> > +static inline unsigned long hash_count(struct ftrace_hash *hash)
> > {
> > return hash ? hash->count : 0;
> > }
> >
> > +unsigned long ftrace_hash_count(struct ftrace_hash *hash)
> > +{
> > + return hash_count(hash);
> > +}
> > +
>
> [Severity: Medium]
> Similarly, does this implementation need to be moved outside the direct
> calls block so it is broadly available to dynamic ftrace?
>
> --
> Sashiko AI review · https://sashiko.dev/#/patchset/20260603110554.29590-2-jolsa@kernel.org?part=1
next prev parent reply other threads:[~2026-06-04 7:59 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-03 11:05 [PATCHv7 bpf-next 00/29] bpf: tracing_multi link Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 01/29] ftrace: Add ftrace_hash_count function Jiri Olsa
2026-06-03 11:26 ` sashiko-bot
2026-06-04 7:59 ` Jiri Olsa [this message]
2026-06-03 11:05 ` [PATCHv7 bpf-next 02/29] ftrace: Add ftrace_hash_remove function Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 03/29] ftrace: Add add_ftrace_hash_entry function Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 04/29] bpf: Use mutex lock pool for bpf trampolines Jiri Olsa
2026-06-03 11:28 ` sashiko-bot
2026-06-04 7:59 ` Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 05/29] bpf: Add struct bpf_trampoline_ops object Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 06/29] bpf: Move trampoline image setup into bpf_trampoline_ops callbacks Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 07/29] bpf: Add bpf_trampoline_add/remove_prog functions Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 08/29] bpf: Add struct bpf_tramp_node object Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 09/29] bpf: Factor fsession link to use struct bpf_tramp_node Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 10/29] bpf: Add multi tracing attach types Jiri Olsa
2026-06-03 11:37 ` sashiko-bot
2026-06-04 8:00 ` Jiri Olsa
2026-06-03 11:52 ` bot+bpf-ci
2026-06-03 11:05 ` [PATCHv7 bpf-next 11/29] bpf: Move sleepable verification code to btf_id_allow_sleepable Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 12/29] bpf: Add bpf_trampoline_multi_attach/detach functions Jiri Olsa
2026-06-03 11:52 ` bot+bpf-ci
2026-06-03 11:05 ` [PATCHv7 bpf-next 13/29] bpf: Add support for tracing multi link Jiri Olsa
2026-06-03 11:41 ` sashiko-bot
2026-06-04 8:00 ` Jiri Olsa
2026-06-03 11:52 ` bot+bpf-ci
2026-06-04 8:00 ` Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 14/29] bpf: Add support for tracing_multi link cookies Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 15/29] bpf: Add support for tracing_multi link session Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 16/29] bpf: Add support for tracing_multi link fdinfo Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 17/29] libbpf: Add bpf_object_cleanup_btf function Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 18/29] libbpf: Add bpf_link_create support for tracing_multi link Jiri Olsa
2026-06-03 11:34 ` sashiko-bot
2026-06-04 7:59 ` Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 19/29] libbpf: Add btf_type_is_traceable_func function Jiri Olsa
2026-06-03 11:36 ` sashiko-bot
2026-06-04 7:59 ` Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 20/29] libbpf: Add support to create tracing multi link Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 21/29] selftests/bpf: Add tracing multi skel/pattern/ids attach tests Jiri Olsa
2026-06-03 13:40 ` sashiko-bot
2026-06-04 8:00 ` Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 22/29] selftests/bpf: Add tracing multi skel/pattern/ids module " Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 23/29] selftests/bpf: Add tracing multi intersect tests Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 24/29] selftests/bpf: Add tracing multi cookies test Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 25/29] selftests/bpf: Add tracing multi session test Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 26/29] selftests/bpf: Add tracing multi attach fails test Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 27/29] selftests/bpf: Add tracing multi verifier " Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 28/29] selftests/bpf: Add tracing multi attach benchmark test Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 29/29] selftests/bpf: Add tracing multi attach rollback tests Jiri Olsa
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