From: Hsuan-Chi Kuo <hsuanchikuo@gmail.com>
To: bpf@vger.kernel.org
Subject: Why does tail call only unwind the current stack frame instead of resetting the current stack?
Date: Sun, 12 Sep 2021 12:48:25 -0500 [thread overview]
Message-ID: <93b37b05-3aab-3e50-bd1b-e97a8d5776f2@gmail.com> (raw)
Hi,
The function check_max_stack_depth
(https://elixir.bootlin.com/linux/latest/source/kernel/bpf/verifier.c#L3574)
is used to ensure the stack size is no greater than 8KB.
The stack can only grow over 8KB because of tail calls as they only
unwind the current stack frame. I wonder why not make tail call reset
the stack since what was on the stack
will never be used again?
Thanks
next reply other threads:[~2021-09-12 17:48 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-12 17:48 Hsuan-Chi Kuo [this message]
2021-09-13 4:08 ` Why does tail call only unwind the current stack frame instead of resetting the current stack? Yonghong Song
2021-09-13 5:04 ` Hsuan-Chi Kuo
2021-09-13 16:32 ` Alexei Starovoitov
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