From: Steven Rostedt <rostedt@goodmis.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Daniel Micay <danielmicay@gmail.com>,
Ingo Molnar <mingo@kernel.org>, Kees Cook <keescook@chromium.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Alexander Popov <alex.popov@linux.com>,
Kernel Hardening <kernel-hardening@lists.openwall.com>,
PaX Team <pageexec@freemail.hu>,
Brad Spengler <spender@grsecurity.net>,
Andy Lutomirski <luto@kernel.org>,
Tycho Andersen <tycho@tycho.ws>,
Laura Abbott <labbott@redhat.com>,
Mark Rutland <mark.rutland@arm.com>,
Borislav Petkov <bp@alien8.de>,
Richard Sandiford <richard.sandiford@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H . Peter Anvin" <hpa@zytor.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
"Dmitry V . Levin" <ldv@altlinux.org>,
Emese Revfy <re.emese@gmail.com>,
Jonathan Corbet <corbet@lwn.net>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Thomas Garnier <thgarnie@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Alexei Starovoitov <ast@kernel.org>, Josef Bacik <jbacik@fb.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Nicholas Piggin <npiggin@gmail.com>,
Al Viro <viro@zeniv.linux.org.uk>,
"David S . Miller" <davem@davemloft.net>,
Ding Tianhong <dingtianhong@huawei.com>,
David Woodhouse <dwmw@amazon.co.uk>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Dominik Brodowski <linux@dominikbrodowski.net>,
Juergen Gross <jgross@suse.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Dan Williams <dan.j.williams@intel.com>,
Mathias Krause <minipli@googlemail.com>,
Vikas Shivappa <vikas.shivappa@linux.intel.com>,
Kyle Huey <me@kylehuey.com>,
Dmitry Safonov <dsafonov@virtuozzo.com>,
Will Deacon <will.deacon@arm.com>, X86 ML <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RFC v9 4/7] x86/entry: Erase kernel stack in syscall_trace_enter()
Date: Tue, 6 Mar 2018 17:29:27 -0500 [thread overview]
Message-ID: <20180306172927.7a975cee@vmware.local.home> (raw)
In-Reply-To: <CA+55aFyv4wDxLQDbzB14HgW8ddu-w2VFteh5JQ57Jkw46mCVAw@mail.gmail.com>
On Tue, 6 Mar 2018 13:47:11 -0800
Linus Torvalds <torvalds@linux-foundation.org> wrote:
> But that's no different from "static variables initialize to zero" and
> nobody sane expects a warning from that. It's just what it is.
Yeah but I would argue that static variables are different. They are
either used in multiple functions or are used for the same function
that maintains its value for multiple calls to that function. Either
way the semantics of a static variable is that it has to be initialized
to something, because you don't know when the first one sets it.
Local variables on the other hand are only in scope of one logical
function algorithm. I've done lots of stupid errors where I may
initialize a local variable in a loop and forget that the loop may
never execute. Sometimes the original value shouldn't be zero, although
most times it is. But that warning has saved me, especially when the
value isn't supposed to be zero.
-- Steve
next prev parent reply other threads:[~2018-03-06 22:29 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-03 20:00 [PATCH RFC v9 0/7] Introduce the STACKLEAK feature and a test for it Alexander Popov
2018-03-03 20:00 ` [PATCH RFC v9 1/7] gcc-plugins: Clean up the cgraph_create_edge* macros Alexander Popov
2018-03-03 20:00 ` [PATCH RFC v9 2/7] x86/entry: Add STACKLEAK erasing the kernel stack at the end of syscalls Alexander Popov
2018-03-05 16:41 ` Dave Hansen
2018-03-05 19:43 ` Laura Abbott
2018-03-05 19:50 ` Dave Hansen
2018-03-05 20:25 ` Peter Zijlstra
2018-03-05 21:21 ` Alexander Popov
2018-03-05 21:36 ` Kees Cook
2018-03-21 11:04 ` Alexander Popov
2018-03-21 15:33 ` Dave Hansen
2018-03-22 20:56 ` Alexander Popov
2018-03-26 17:32 ` Kees Cook
2018-03-26 17:43 ` Andy Lutomirski
2018-03-03 20:00 ` [PATCH RFC v9 3/7] gcc-plugins: Add STACKLEAK plugin for tracking the kernel stack Alexander Popov
2018-03-03 20:00 ` [PATCH RFC v9 4/7] x86/entry: Erase kernel stack in syscall_trace_enter() Alexander Popov
2018-03-05 19:40 ` Dave Hansen
2018-03-05 20:06 ` Kees Cook
2018-03-05 20:15 ` Linus Torvalds
2018-03-05 21:02 ` Alexander Popov
2018-03-05 21:02 ` Kees Cook
2018-03-05 21:40 ` Linus Torvalds
2018-03-05 22:07 ` Linus Torvalds
2018-03-06 0:56 ` Kees Cook
2018-03-06 4:30 ` Linus Torvalds
2018-03-06 17:58 ` Andy Lutomirski
2018-03-06 7:56 ` [OLD PATCH] net: recvmsg: Unconditionally zero struct sockaddr_storage " Ingo Molnar
2018-03-06 8:08 ` Ingo Molnar
2018-03-06 15:16 ` Daniel Micay
2018-03-06 15:28 ` Daniel Micay
2018-03-06 18:56 ` Linus Torvalds
2018-03-06 19:07 ` Peter Zijlstra
2018-03-06 19:07 ` Ard Biesheuvel
2018-03-06 19:16 ` Linus Torvalds
2018-03-06 20:42 ` Arnd Bergmann
2018-03-06 21:01 ` Linus Torvalds
2018-03-06 21:21 ` Arnd Bergmann
2018-03-06 21:29 ` Linus Torvalds
2018-03-06 22:09 ` Arnd Bergmann
2018-03-06 22:24 ` Linus Torvalds
2018-03-06 21:36 ` Steven Rostedt
2018-03-06 21:41 ` Linus Torvalds
2018-03-06 21:47 ` Linus Torvalds
2018-03-06 22:29 ` Steven Rostedt [this message]
2018-03-06 22:41 ` Linus Torvalds
2018-03-06 22:52 ` Steven Rostedt
2018-03-06 23:09 ` Linus Torvalds
2018-03-12 8:22 ` Ingo Molnar
2018-03-12 9:00 ` Ard Biesheuvel
2018-03-12 9:21 ` Ingo Molnar
2018-03-06 21:47 ` Arnd Bergmann
2018-03-06 22:19 ` Linus Torvalds
2018-03-05 20:26 ` Peter Zijlstra
2018-03-03 20:00 ` [PATCH RFC v9 5/7] lkdtm: Add a test for STACKLEAK Alexander Popov
2018-03-03 20:00 ` [PATCH RFC v9 6/7] fs/proc: Show STACKLEAK metrics in the /proc file system Alexander Popov
2018-03-03 20:00 ` [PATCH RFC v9 7/7] doc: self-protection: Add information about STACKLEAK feature Alexander Popov
2018-03-05 19:34 ` [PATCH RFC v9 0/7] Introduce the STACKLEAK feature and a test for it Kees Cook
2018-03-05 19:42 ` Dave Hansen
2018-03-05 20:02 ` Kees Cook
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