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From: Jiri Olsa <jolsa@redhat.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>, Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	netdev@vger.kernel.org, bpf@vger.kernel.org,
	Andrii Nakryiko <andriin@fb.com>, Yonghong Song <yhs@fb.com>,
	Martin KaFai Lau <kafai@fb.com>,
	Jakub Kicinski <jakub.kicinski@netronome.com>,
	David Miller <davem@redhat.com>,
	bjorn.topel@intel.com
Subject: Re: [PATCH 5/5] bpf: Allow to resolve bpf trampoline in unwind
Date: Tue, 7 Jan 2020 14:05:46 +0100	[thread overview]
Message-ID: <20200107130546.GI290055@krava> (raw)
In-Reply-To: <20200106234639.fo2ctgkb5vumayyl@ast-mbp>

On Mon, Jan 06, 2020 at 03:46:40PM -0800, Alexei Starovoitov wrote:
> On Sun, Dec 29, 2019 at 03:37:40PM +0100, Jiri Olsa wrote:
> > When unwinding the stack we need to identify each
> > address to successfully continue. Adding latch tree
> > to keep trampolines for quick lookup during the
> > unwind.
> > 
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ...
> > +bool is_bpf_trampoline(void *addr)
> > +{
> > +	return latch_tree_find(addr, &tree, &tree_ops) != NULL;
> > +}
> > +
> >  struct bpf_trampoline *bpf_trampoline_lookup(u64 key)
> >  {
> >  	struct bpf_trampoline *tr;
> > @@ -65,6 +98,7 @@ struct bpf_trampoline *bpf_trampoline_lookup(u64 key)
> >  	for (i = 0; i < BPF_TRAMP_MAX; i++)
> >  		INIT_HLIST_HEAD(&tr->progs_hlist[i]);
> >  	tr->image = image;
> > +	latch_tree_insert(&tr->tnode, &tree, &tree_ops);
> 
> Thanks for the fix. I was thinking to apply it, but then realized that bpf
> dispatcher logic has the same issue.
> Could you generalize the fix for both?
> May be bpf_jit_alloc_exec_page() can do latch_tree_insert() ?
> and new version of bpf_jit_free_exec() is needed that will do latch_tree_erase().
> Wdyt?

I need to check the dispatcher code, but seems ok.. will check

jirka


  parent reply	other threads:[~2020-01-07 13:05 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-29 14:37 [RFC 0/5] bpf: Add trampoline helpers Jiri Olsa
2019-12-29 14:37 ` [PATCH 1/5] bpf: Allow non struct type for btf ctx access Jiri Olsa
2020-01-06 21:36   ` Yonghong Song
2020-01-07 12:13     ` Jiri Olsa
2020-01-07 15:50       ` Jiri Olsa
2020-01-07 17:55         ` Yonghong Song
2020-01-07 18:28           ` Yonghong Song
2020-01-08 14:38             ` Jiri Olsa
2019-12-29 14:37 ` [PATCH 2/5] bpf: Add bpf_perf_event_output_kfunc Jiri Olsa
2020-01-06 23:27   ` Alexei Starovoitov
2020-01-07 12:25     ` Jiri Olsa
2020-01-07 22:13       ` Alexei Starovoitov
2020-01-08 10:24         ` Jiri Olsa
2019-12-29 14:37 ` [PATCH 3/5] bpf: Add bpf_get_stackid_kfunc Jiri Olsa
2019-12-29 14:37 ` [PATCH 4/5] bpf: Add bpf_get_stack_kfunc Jiri Olsa
2019-12-29 14:37 ` [PATCH 5/5] bpf: Allow to resolve bpf trampoline in unwind Jiri Olsa
2020-01-06 23:46   ` Alexei Starovoitov
2020-01-07  8:30     ` Daniel Borkmann
2020-01-07 13:15       ` Jiri Olsa
2020-01-07 19:30         ` Daniel Borkmann
2020-01-07 13:05     ` Jiri Olsa [this message]
2020-01-07 13:30       ` Björn Töpel
2020-01-13  9:43         ` Jiri Olsa
2020-01-13 12:21           ` Björn Töpel
2020-01-13 12:31             ` Björn Töpel
2020-01-13 12:37               ` Jiri Olsa
2020-02-03 19:58                 ` Jiri Olsa
2020-02-03 20:27                   ` Björn Töpel
2020-02-03 20:45                     ` Toke Høiland-Jørgensen
2020-02-04  8:18                     ` Jiri Olsa

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