From: Oleg Nesterov <oleg@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Enke Chen <enkechen@cisco.com>, Dave Martin <Dave.Martin@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Peter Zijlstra <peterz@infradead.org>,
Arnd Bergmann <arnd@arndb.de>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Khalid Aziz <khalid.aziz@oracle.com>,
Kate Stewart <kstewart@linuxfoundation.org>,
Helge Deller <deller@gmx.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <christian@brauner.io>,
Catalin Marinas <Catalin.Marinas@arm.com>,
Will Deacon <Will.Deacon@arm.com>,
Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
Michal Hocko <mhocko@kernel.org>, Rik van Riel <riel@surriel.com>
Subject: Re: [PATCH v5 1/2] kernel/signal: Signal-based pre-coredump notification
Date: Thu, 6 Dec 2018 18:29:32 +0100 [thread overview]
Message-ID: <20181206172931.GA12967@redhat.com> (raw)
In-Reply-To: <20181204143759.fe24ee036a33000193339561@linux-foundation.org>
On 12/04, Andrew Morton wrote:
>
> I'm not sure what to make of this patchset, really. Oleg sounds
> unhappy and that's always a bad sign. And signals are rather ugly
> things. Oleg, can you please expand on your concerns?
I don't really know what can I say...
Yes the signals are ugly things, this is one reason. Worse, you need to
use real-time predump_signal if parent has 2 or more children.
And when it comes to child-parent notifications we already have do_wait().
So probably it would be better to implement WCOREDUMP so that the parent
could rely on SIGCHLD + waitpid(WCOREDUMP). Not that I think this is a
good idea and this is much more complex especially if we want to report
this event to ptracer too, while this patch is very simple.
In fact I think that we need something more generic, but I can't suggest
any good idea :/
May be we could simply add a tracepoint or perf_event_coredump, I dunno.
Sure, the usage of perf events is not that simple...
Oleg.
WARNING: multiple messages have this Message-ID (diff)
From: Oleg Nesterov <oleg@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Enke Chen <enkechen@cisco.com>, Dave Martin <Dave.Martin@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Peter Zijlstra <peterz@infradead.org>,
Arnd Bergmann <arnd@arndb.de>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Khalid Aziz <khalid.aziz@oracle.com>,
Kate Stewart <kstewart@linuxfoundation.org>,
Helge Deller <deller@gmx.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <christian@brauner.io>,
Catalin Marinas <Catalin.Marinas@arm.com>,
Will Deacon <Will.Deacon@arm.com>,
Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
Michal Hocko <mhocko@kernel.org>, Rik van Riel <riel@surriel.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Roman Gushchin <guro@fb.com>,
Marcos Paulo de Souza <marcos.souza.org@gmail.com>,
Dominik Brodowski <linux@dominikbrodowski.net>,
Cyrill Gorcunov <gorcunov@openvz.org>,
Yang Shi <yang.shi@linux.alibaba.com>,
Jann Horn <jannh@google.com>, Kees Cook <keescook@chromium.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
"Victor Kamensky (kamensky)" <kamensky@cisco.com>,
"xe-linux-external@cisco.com" <xe-linux-external@cisco.com>,
Stefan Strogin <sstrogin@cisco.com>
Subject: Re: [PATCH v5 1/2] kernel/signal: Signal-based pre-coredump notification
Date: Thu, 6 Dec 2018 18:29:32 +0100 [thread overview]
Message-ID: <20181206172931.GA12967@redhat.com> (raw)
Message-ID: <20181206172932.nZ-5gZ0WZSM6jcD26R4aTfTtJV9nh99m9J3sPs3276k@z> (raw)
In-Reply-To: <20181204143759.fe24ee036a33000193339561@linux-foundation.org>
On 12/04, Andrew Morton wrote:
>
> I'm not sure what to make of this patchset, really. Oleg sounds
> unhappy and that's always a bad sign. And signals are rather ugly
> things. Oleg, can you please expand on your concerns?
I don't really know what can I say...
Yes the signals are ugly things, this is one reason. Worse, you need to
use real-time predump_signal if parent has 2 or more children.
And when it comes to child-parent notifications we already have do_wait().
So probably it would be better to implement WCOREDUMP so that the parent
could rely on SIGCHLD + waitpid(WCOREDUMP). Not that I think this is a
good idea and this is much more complex especially if we want to report
this event to ptracer too, while this patch is very simple.
In fact I think that we need something more generic, but I can't suggest
any good idea :/
May be we could simply add a tracepoint or perf_event_coredump, I dunno.
Sure, the usage of perf events is not that simple...
Oleg.
next prev parent reply other threads:[~2018-12-06 17:29 UTC|newest]
Thread overview: 148+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-13 0:33 [PATCH] kernel/signal: Signal-based pre-coredump notification Enke Chen
2018-10-13 0:33 ` Enke Chen
2018-10-13 6:40 ` Greg Kroah-Hartman
2018-10-13 6:40 ` Greg Kroah-Hartman
2018-10-15 18:16 ` Enke Chen
2018-10-15 18:16 ` Enke Chen
2018-10-15 18:43 ` Greg Kroah-Hartman
2018-10-15 18:43 ` Greg Kroah-Hartman
2018-10-15 18:49 ` Enke Chen
2018-10-15 18:49 ` Enke Chen
2018-10-15 18:58 ` Greg Kroah-Hartman
2018-10-15 18:58 ` Greg Kroah-Hartman
2018-10-13 10:44 ` Christian Brauner
2018-10-13 10:44 ` Christian Brauner
2018-10-15 18:39 ` Enke Chen
2018-10-15 18:39 ` Enke Chen
2018-10-15 18:39 ` Enke Chen
2018-10-13 18:27 ` Jann Horn
2018-10-13 18:27 ` Jann Horn
2018-10-15 18:36 ` Enke Chen
2018-10-15 18:36 ` Enke Chen
2018-10-15 18:54 ` Jann Horn
2018-10-15 18:54 ` Jann Horn
2018-10-15 19:23 ` Enke Chen
2018-10-15 19:23 ` Enke Chen
2018-10-19 23:01 ` Enke Chen
2018-10-19 23:01 ` Enke Chen
2018-10-22 15:40 ` Jann Horn
2018-10-22 15:40 ` Jann Horn
2018-10-22 20:48 ` Enke Chen
2018-10-22 20:48 ` Enke Chen
2018-10-15 12:05 ` Oleg Nesterov
2018-10-15 12:05 ` Oleg Nesterov
2018-10-15 18:54 ` Enke Chen
2018-10-15 18:54 ` Enke Chen
2018-10-15 19:17 ` Enke Chen
2018-10-15 19:17 ` Enke Chen
2018-10-15 19:26 ` Enke Chen
2018-10-15 19:26 ` Enke Chen
2018-10-16 14:14 ` Oleg Nesterov
2018-10-16 14:14 ` Oleg Nesterov
2018-10-16 15:09 ` Eric W. Biederman
2018-10-16 15:09 ` Eric W. Biederman
2018-10-16 15:09 ` Eric W. Biederman
2018-10-17 0:39 ` Enke Chen
2018-10-17 0:39 ` Enke Chen
2018-10-15 21:21 ` Alan Cox
2018-10-15 21:21 ` Alan Cox
2018-10-15 21:31 ` Enke Chen
2018-10-15 21:31 ` Enke Chen
2018-10-15 23:28 ` Eric W. Biederman
2018-10-15 23:28 ` Eric W. Biederman
2018-10-15 23:28 ` Eric W. Biederman
2018-10-16 0:33 ` valdis.kletnieks
2018-10-16 0:33 ` valdis.kletnieks
2018-10-16 0:33 ` valdis.kletnieks
2018-10-16 0:54 ` Enke Chen
2018-10-16 0:54 ` Enke Chen
2018-10-16 15:26 ` Eric W. Biederman
2018-10-16 15:26 ` Eric W. Biederman
2018-10-16 15:26 ` Eric W. Biederman
2018-10-22 21:09 ` [PATCH v2] " Enke Chen
2018-10-22 21:09 ` Enke Chen
2018-10-23 9:23 ` Oleg Nesterov
2018-10-23 9:23 ` Oleg Nesterov
2018-10-23 19:43 ` Enke Chen
2018-10-23 19:43 ` Enke Chen
2018-10-23 21:40 ` Enke Chen
2018-10-23 21:40 ` Enke Chen
2018-10-24 13:52 ` Oleg Nesterov
2018-10-24 13:52 ` Oleg Nesterov
2018-10-24 21:56 ` Enke Chen
2018-10-24 21:56 ` Enke Chen
2018-10-24 5:39 ` [PATCH v3] " Enke Chen
2018-10-24 5:39 ` Enke Chen
2018-10-24 14:02 ` Oleg Nesterov
2018-10-24 14:02 ` Oleg Nesterov
2018-10-24 22:02 ` Enke Chen
2018-10-24 22:02 ` Enke Chen
2018-10-25 22:56 ` [PATCH v4] " Enke Chen
2018-10-25 22:56 ` Enke Chen
2018-10-26 8:28 ` Oleg Nesterov
2018-10-26 8:28 ` Oleg Nesterov
2018-10-26 22:23 ` Enke Chen
2018-10-26 22:23 ` Enke Chen
2018-10-29 11:18 ` Oleg Nesterov
2018-10-29 11:18 ` Oleg Nesterov
2018-10-29 21:08 ` Enke Chen
2018-10-29 21:08 ` Enke Chen
2018-10-29 22:31 ` [PATCH v5] " Enke Chen
2018-10-29 22:31 ` Enke Chen
2018-10-30 16:46 ` Oleg Nesterov
2018-10-30 16:46 ` Oleg Nesterov
2018-10-31 0:25 ` Enke Chen
2018-10-31 0:25 ` Enke Chen
2018-11-22 0:37 ` Andrew Morton
2018-11-22 0:37 ` Andrew Morton
2018-11-22 1:09 ` Enke Chen
2018-11-22 1:09 ` Enke Chen
2018-11-22 1:18 ` Enke Chen
2018-11-22 1:18 ` Enke Chen
2018-11-22 1:33 ` Andrew Morton
2018-11-22 1:33 ` Andrew Morton
2018-11-22 4:57 ` Enke Chen
2018-11-22 4:57 ` Enke Chen
2018-11-12 23:22 ` Enke Chen
2018-11-12 23:22 ` Enke Chen
2018-11-27 22:54 ` [PATCH v5 1/2] " Enke Chen
2018-11-27 22:54 ` Enke Chen
2018-11-28 15:19 ` Dave Martin
2018-11-28 15:19 ` Dave Martin
2018-11-29 0:15 ` Enke Chen
2018-11-29 0:15 ` Enke Chen
2018-11-29 11:55 ` Dave Martin
2018-11-29 11:55 ` Dave Martin
2018-11-30 0:27 ` Enke Chen
2018-11-30 0:27 ` Enke Chen
2018-11-30 12:03 ` Oleg Nesterov
2018-11-30 12:03 ` Oleg Nesterov
2018-12-05 6:47 ` Jann Horn
2018-12-05 6:47 ` Jann Horn
2018-12-04 22:37 ` Andrew Morton
2018-12-04 22:37 ` Andrew Morton
2018-12-06 17:29 ` Oleg Nesterov [this message]
2018-12-06 17:29 ` Oleg Nesterov
2018-10-25 22:56 ` [PATCH] selftests/prctl: selftest for pre-coredump signal notification Enke Chen
2018-10-25 22:56 ` Enke Chen
2018-11-27 22:54 ` [PATCH v5 2/2] " Enke Chen
2018-11-27 22:54 ` Enke Chen
2018-10-24 13:29 ` [PATCH v2] kernel/signal: Signal-based pre-coredump notification Eric W. Biederman
2018-10-24 13:29 ` Eric W. Biederman
2018-10-24 13:29 ` Eric W. Biederman
2018-10-24 23:50 ` Enke Chen
2018-10-24 23:50 ` Enke Chen
2018-10-25 12:23 ` Eric W. Biederman
2018-10-25 12:23 ` Eric W. Biederman
2018-10-25 12:23 ` Eric W. Biederman
2018-10-25 20:45 ` Enke Chen
2018-10-25 20:45 ` Enke Chen
2018-10-25 21:24 ` Enke Chen
2018-10-25 21:24 ` Enke Chen
2018-10-25 21:56 ` Enke Chen
2018-10-25 21:56 ` Enke Chen
2018-10-25 13:45 ` Jann Horn
2018-10-25 13:45 ` Jann Horn
2018-10-25 20:21 ` Eric W. Biederman
2018-10-25 20:21 ` Eric W. Biederman
2018-10-25 20:21 ` Eric W. Biederman
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