| Message ID | 171318568081.254850.16193015880509111721.stgit@devnote2 (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | BPF |
| Headers | show |
| Series | tracing: fprobe: function_graph: Multi-function graph and fprobe on fgraph | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Guessing tree name failed - patch did not apply |
| bpf/vmtest-bpf-PR | fail | merge-conflict |
On Mon, Apr 15, 2024 at 6:22 AM Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote: > > From: Masami Hiramatsu (Google) <mhiramat@kernel.org> > > Enable kprobe_multi feature if CONFIG_FPROBE is enabled. The pt_regs is > converted from ftrace_regs by ftrace_partial_regs(), thus some registers > may always returns 0. But it should be enough for function entry (access > arguments) and exit (access return value). > > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> > Acked-by: Florent Revest <revest@chromium.org> > --- > Changes from previous series: NOTHING, Update against the new series. > --- > kernel/trace/bpf_trace.c | 22 +++++++++------------- > 1 file changed, 9 insertions(+), 13 deletions(-) > > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > index e51a6ef87167..57b1174030c9 100644 > --- a/kernel/trace/bpf_trace.c > +++ b/kernel/trace/bpf_trace.c > @@ -2577,7 +2577,7 @@ static int __init bpf_event_init(void) > fs_initcall(bpf_event_init); > #endif /* CONFIG_MODULES */ > > -#if defined(CONFIG_FPROBE) && defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) > +#ifdef CONFIG_FPROBE > struct bpf_kprobe_multi_link { > struct bpf_link link; > struct fprobe fp; > @@ -2600,6 +2600,8 @@ struct user_syms { > char *buf; > }; > > +static DEFINE_PER_CPU(struct pt_regs, bpf_kprobe_multi_pt_regs); this is a waste if CONFIG_HAVE_PT_REGS_TO_FTRACE_REGS_CAST=y, right? Can we guard it? > + > static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms, u32 cnt) > { > unsigned long __user usymbol; > @@ -2792,13 +2794,14 @@ static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx) > > static int > kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, > - unsigned long entry_ip, struct pt_regs *regs) > + unsigned long entry_ip, struct ftrace_regs *fregs) > { > struct bpf_kprobe_multi_run_ctx run_ctx = { > .link = link, > .entry_ip = entry_ip, > }; > struct bpf_run_ctx *old_run_ctx; > + struct pt_regs *regs; > int err; > > if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) { > @@ -2809,6 +2812,7 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, > > migrate_disable(); > rcu_read_lock(); > + regs = ftrace_partial_regs(fregs, this_cpu_ptr(&bpf_kprobe_multi_pt_regs)); and then pass NULL if defined(CONFIG_HAVE_PT_REGS_TO_FTRACE_REGS_CAST)? > old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx); > err = bpf_prog_run(link->link.prog, regs); > bpf_reset_run_ctx(old_run_ctx); > @@ -2826,13 +2830,9 @@ kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip, > void *data) > { > struct bpf_kprobe_multi_link *link; > - struct pt_regs *regs = ftrace_get_regs(fregs); > - > - if (!regs) > - return 0; > > link = container_of(fp, struct bpf_kprobe_multi_link, fp); > - kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs); > + kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), fregs); > return 0; > } > > @@ -2842,13 +2842,9 @@ kprobe_multi_link_exit_handler(struct fprobe *fp, unsigned long fentry_ip, > void *data) > { > struct bpf_kprobe_multi_link *link; > - struct pt_regs *regs = ftrace_get_regs(fregs); > - > - if (!regs) > - return; > > link = container_of(fp, struct bpf_kprobe_multi_link, fp); > - kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs); > + kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), fregs); > } > > static int symbols_cmp_r(const void *a, const void *b, const void *priv) > @@ -3107,7 +3103,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr > kvfree(cookies); > return err; > } > -#else /* !CONFIG_FPROBE || !CONFIG_DYNAMIC_FTRACE_WITH_REGS */ > +#else /* !CONFIG_FPROBE */ > int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) > { > return -EOPNOTSUPP; > >
On Thu, 25 Apr 2024 13:09:32 -0700 Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote: > On Mon, Apr 15, 2024 at 6:22 AM Masami Hiramatsu (Google) > <mhiramat@kernel.org> wrote: > > > > From: Masami Hiramatsu (Google) <mhiramat@kernel.org> > > > > Enable kprobe_multi feature if CONFIG_FPROBE is enabled. The pt_regs is > > converted from ftrace_regs by ftrace_partial_regs(), thus some registers > > may always returns 0. But it should be enough for function entry (access > > arguments) and exit (access return value). > > > > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> > > Acked-by: Florent Revest <revest@chromium.org> > > --- > > Changes from previous series: NOTHING, Update against the new series. > > --- > > kernel/trace/bpf_trace.c | 22 +++++++++------------- > > 1 file changed, 9 insertions(+), 13 deletions(-) > > > > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > > index e51a6ef87167..57b1174030c9 100644 > > --- a/kernel/trace/bpf_trace.c > > +++ b/kernel/trace/bpf_trace.c > > @@ -2577,7 +2577,7 @@ static int __init bpf_event_init(void) > > fs_initcall(bpf_event_init); > > #endif /* CONFIG_MODULES */ > > > > -#if defined(CONFIG_FPROBE) && defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) > > +#ifdef CONFIG_FPROBE > > struct bpf_kprobe_multi_link { > > struct bpf_link link; > > struct fprobe fp; > > @@ -2600,6 +2600,8 @@ struct user_syms { > > char *buf; > > }; > > > > +static DEFINE_PER_CPU(struct pt_regs, bpf_kprobe_multi_pt_regs); > > this is a waste if CONFIG_HAVE_PT_REGS_TO_FTRACE_REGS_CAST=y, right? > Can we guard it? Good catch! Yes, we can guard it. > > > > + > > static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms, u32 cnt) > > { > > unsigned long __user usymbol; > > @@ -2792,13 +2794,14 @@ static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx) > > > > static int > > kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, > > - unsigned long entry_ip, struct pt_regs *regs) > > + unsigned long entry_ip, struct ftrace_regs *fregs) > > { > > struct bpf_kprobe_multi_run_ctx run_ctx = { > > .link = link, > > .entry_ip = entry_ip, > > }; > > struct bpf_run_ctx *old_run_ctx; > > + struct pt_regs *regs; > > int err; > > > > if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) { > > @@ -2809,6 +2812,7 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, > > > > migrate_disable(); > > rcu_read_lock(); > > + regs = ftrace_partial_regs(fregs, this_cpu_ptr(&bpf_kprobe_multi_pt_regs)); > > and then pass NULL if defined(CONFIG_HAVE_PT_REGS_TO_FTRACE_REGS_CAST)? Indeed. Thank you! > > > > old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx); > > err = bpf_prog_run(link->link.prog, regs); > > bpf_reset_run_ctx(old_run_ctx); > > @@ -2826,13 +2830,9 @@ kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip, > > void *data) > > { > > struct bpf_kprobe_multi_link *link; > > - struct pt_regs *regs = ftrace_get_regs(fregs); > > - > > - if (!regs) > > - return 0; > > > > link = container_of(fp, struct bpf_kprobe_multi_link, fp); > > - kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs); > > + kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), fregs); > > return 0; > > } > > > > @@ -2842,13 +2842,9 @@ kprobe_multi_link_exit_handler(struct fprobe *fp, unsigned long fentry_ip, > > void *data) > > { > > struct bpf_kprobe_multi_link *link; > > - struct pt_regs *regs = ftrace_get_regs(fregs); > > - > > - if (!regs) > > - return; > > > > link = container_of(fp, struct bpf_kprobe_multi_link, fp); > > - kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs); > > + kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), fregs); > > } > > > > static int symbols_cmp_r(const void *a, const void *b, const void *priv) > > @@ -3107,7 +3103,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr > > kvfree(cookies); > > return err; > > } > > -#else /* !CONFIG_FPROBE || !CONFIG_DYNAMIC_FTRACE_WITH_REGS */ > > +#else /* !CONFIG_FPROBE */ > > int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) > > { > > return -EOPNOTSUPP; > > > >
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index e51a6ef87167..57b1174030c9 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2577,7 +2577,7 @@ static int __init bpf_event_init(void) fs_initcall(bpf_event_init); #endif /* CONFIG_MODULES */ -#if defined(CONFIG_FPROBE) && defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) +#ifdef CONFIG_FPROBE struct bpf_kprobe_multi_link { struct bpf_link link; struct fprobe fp; @@ -2600,6 +2600,8 @@ struct user_syms { char *buf; }; +static DEFINE_PER_CPU(struct pt_regs, bpf_kprobe_multi_pt_regs); + static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms, u32 cnt) { unsigned long __user usymbol; @@ -2792,13 +2794,14 @@ static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx) static int kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, - unsigned long entry_ip, struct pt_regs *regs) + unsigned long entry_ip, struct ftrace_regs *fregs) { struct bpf_kprobe_multi_run_ctx run_ctx = { .link = link, .entry_ip = entry_ip, }; struct bpf_run_ctx *old_run_ctx; + struct pt_regs *regs; int err; if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) { @@ -2809,6 +2812,7 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, migrate_disable(); rcu_read_lock(); + regs = ftrace_partial_regs(fregs, this_cpu_ptr(&bpf_kprobe_multi_pt_regs)); old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx); err = bpf_prog_run(link->link.prog, regs); bpf_reset_run_ctx(old_run_ctx); @@ -2826,13 +2830,9 @@ kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip, void *data) { struct bpf_kprobe_multi_link *link; - struct pt_regs *regs = ftrace_get_regs(fregs); - - if (!regs) - return 0; link = container_of(fp, struct bpf_kprobe_multi_link, fp); - kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs); + kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), fregs); return 0; } @@ -2842,13 +2842,9 @@ kprobe_multi_link_exit_handler(struct fprobe *fp, unsigned long fentry_ip, void *data) { struct bpf_kprobe_multi_link *link; - struct pt_regs *regs = ftrace_get_regs(fregs); - - if (!regs) - return; link = container_of(fp, struct bpf_kprobe_multi_link, fp); - kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs); + kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), fregs); } static int symbols_cmp_r(const void *a, const void *b, const void *priv) @@ -3107,7 +3103,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr kvfree(cookies); return err; } -#else /* !CONFIG_FPROBE || !CONFIG_DYNAMIC_FTRACE_WITH_REGS */ +#else /* !CONFIG_FPROBE */ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) { return -EOPNOTSUPP;