From: Oleg Nesterov <oleg@redhat.com>
To: Gregory Price <gregory.price@memverge.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
Gregory Price <gourry.memverge@gmail.com>,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Linux-Arch <linux-arch@vger.kernel.org>,
avagin@gmail.com, Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>,
krisman@collabora.com, Thomas Gleixner <tglx@linutronix.de>,
Jonathan Corbet <corbet@lwn.net>, shuah <shuah@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
tongtiangen@huawei.com, Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH v14 1/4] asm-generic,arm64: create task variant of access_ok
Date: Thu, 30 Mar 2023 01:54:43 +0200 [thread overview]
Message-ID: <20230329235442.GA10790@redhat.com> (raw)
In-Reply-To: <ZCQMsWNfkMJ0xHSy@memverge.com>
On 03/29, Gregory Price wrote:
>
> Last note on this before I push up another patch set.
>
> The change from __get_user to get_user also introduces a call to
> might_fault() which adds a larger callstack for every syscall /
> dispatch. This turns into a might_sleep and might_reschedule, which
> represent a very different pattern of execution from before.
might_fault() is nop unless CONFIG_PROVE_LOCKING || DEBUG_ATOMIC_SLEEP.
Again, I won't really argue with task_access_ok(). Just I am not sure
2/4 gives enough justification for this new helper with unclear semantics
(until we ensure that access_ok() doesn't depend on current).
Oleg.
next prev parent reply other threads:[~2023-03-29 23:55 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-28 16:48 [PATCH v14 0/4] Checkpoint Support for Syscall User Dispatch Gregory Price
2023-03-28 16:48 ` [PATCH v14 1/4] asm-generic,arm64: create task variant of access_ok Gregory Price
2023-03-28 18:46 ` Arnd Bergmann
2023-03-29 15:15 ` Oleg Nesterov
2023-03-29 15:41 ` Arnd Bergmann
2023-03-29 16:03 ` Oleg Nesterov
2023-03-29 3:56 ` Gregory Price
2023-03-29 17:13 ` Oleg Nesterov
2023-03-29 5:37 ` Gregory Price
2023-03-29 17:58 ` Oleg Nesterov
2023-03-29 5:54 ` Gregory Price
2023-03-29 18:13 ` Oleg Nesterov
2023-03-29 10:02 ` Gregory Price
2023-03-29 23:54 ` Oleg Nesterov [this message]
2023-03-29 18:29 ` Arnd Bergmann
2023-03-29 16:22 ` Catalin Marinas
2023-03-29 4:34 ` Gregory Price
2023-03-30 14:05 ` Catalin Marinas
2023-03-30 4:18 ` Gregory Price
2023-03-28 16:48 ` [PATCH v14 2/4] syscall_user_dispatch: helper function to operate on given task Gregory Price
2023-03-28 16:48 ` [PATCH v14 3/4] ptrace,syscall_user_dispatch: checkpoint/restore support for SUD Gregory Price
2023-03-28 16:48 ` [PATCH v14 4/4] selftest,ptrace: Add selftest for syscall user dispatch config api Gregory Price
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