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From: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
To: "olsajiri@gmail.com" <olsajiri@gmail.com>,
	"oleg@redhat.com" <oleg@redhat.com>
Cc: "songliubraving@fb.com" <songliubraving@fb.com>,
	"luto@kernel.org" <luto@kernel.org>,
	"mhiramat@kernel.org" <mhiramat@kernel.org>,
	"andrii@kernel.org" <andrii@kernel.org>,
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	"linux-trace-kernel@vger.kernel.org"
	<linux-trace-kernel@vger.kernel.org>,
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	"bpf@vger.kernel.org" <bpf@vger.kernel.org>,
	"x86@kernel.org" <x86@kernel.org>
Subject: Re: [PATCHv5 bpf-next 6/8] x86/shstk: Add return uprobe support
Date: Wed, 15 May 2024 15:18:39 +0000	[thread overview]
Message-ID: <5ed6178867d36ae1bd133935f066c40daab649d9.camel@intel.com> (raw)
In-Reply-To: <ZkTIU1QUAJF0f0KK@krava>

On Wed, 2024-05-15 at 08:36 -0600, Jiri Olsa wrote:
> > 
> > Let me ask a couple of really stupid questions. What if the shadow stack
> > is "shorter" than the normal stack? I mean,

The shadow stack could overflow if it is not big enough. However since the
normal stack has return addresses and data, and shadow stack has the smaller
amount data of only return addresses, we can mostly avoid this by picking a
large size for the shadow stack.

For underflow, you can't return from the point where you enable shadow stack.
Almost all uses will enable it very early. Glibc loader does it before main is
reached, for example. The shadow stack selftest is not a typical usage in this
respect.

  reply	other threads:[~2024-05-15 15:18 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-07 10:53 [PATCHv5 bpf-next 0/8] uprobe: uretprobe speed up Jiri Olsa
2024-05-07 10:53 ` [PATCHv5 bpf-next 1/8] uprobe: Wire up uretprobe system call Jiri Olsa
2024-05-07 10:53 ` [PATCHv5 bpf-next 2/8] uprobe: Add uretprobe syscall to speed up return probe Jiri Olsa
2024-05-07 10:53 ` [PATCHv5 bpf-next 3/8] selftests/bpf: Add uretprobe syscall test for regs integrity Jiri Olsa
2024-05-07 10:53 ` [PATCHv5 bpf-next 4/8] selftests/bpf: Add uretprobe syscall test for regs changes Jiri Olsa
2024-05-07 10:53 ` [PATCHv5 bpf-next 5/8] selftests/bpf: Add uretprobe syscall call from user space test Jiri Olsa
2024-05-07 16:57   ` Andrii Nakryiko
2024-05-07 10:53 ` [PATCHv5 bpf-next 6/8] x86/shstk: Add return uprobe support Jiri Olsa
2024-05-07 17:35   ` Edgecombe, Rick P
2024-05-09  8:30     ` Jiri Olsa
2024-05-09 16:24       ` Edgecombe, Rick P
2024-05-11 21:09         ` Jiri Olsa
2024-05-13  9:50           ` Masami Hiramatsu
2024-05-13 17:12             ` Edgecombe, Rick P
2024-05-13 21:23               ` Jiri Olsa
2024-05-15  1:10                 ` Edgecombe, Rick P
2024-05-15  1:44                   ` Deepak Gupta
2024-05-15 11:19                     ` Oleg Nesterov
2024-05-15 14:36                       ` Jiri Olsa
2024-05-15 15:18                         ` Edgecombe, Rick P [this message]
2024-05-15 15:26                         ` Oleg Nesterov
2024-05-15 15:31                           ` Edgecombe, Rick P
2024-05-15 11:35                 ` Oleg Nesterov
2024-05-15 15:13                   ` Edgecombe, Rick P
2024-05-15 15:42                     ` Oleg Nesterov
2024-05-19 22:18                       ` Jiri Olsa
2024-05-21  1:31                         ` Edgecombe, Rick P
2024-05-21 10:11                           ` Jiri Olsa
2024-05-07 10:53 ` [PATCHv5 bpf-next 7/8] selftests/x86: Add return uprobe shadow stack test Jiri Olsa
2024-05-13  9:45   ` Masami Hiramatsu
2024-05-13 21:28     ` Jiri Olsa
2024-05-07 10:53 ` [PATCHv5 8/8] man2: Add uretprobe syscall page Jiri Olsa

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