From: Linus Torvalds <torvalds@linux-foundation.org>
To: Bernd Edlinger <bernd.edlinger@hotmail.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
Jann Horn <jannh@google.com>,
Vasiliy Kulikov <segoon@openwall.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Oleg Nesterov <oleg@redhat.com>,
Cyrill Gorcunov <gorcunov@gmail.com>,
Sargun Dhillon <sargun@sargun.me>,
Christian Brauner <christian.brauner@ubuntu.com>,
Arnd Bergmann <arnd@arndb.de>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Waiman Long <longman@redhat.com>,
Davidlohr Bueso <dave@stgolabs.net>
Subject: Re: [PATCH 3/3] exec: Transform exec_update_mutex into a rw_semaphore
Date: Fri, 4 Dec 2020 12:48:18 -0800 [thread overview]
Message-ID: <CAHk-=wgxe-KAqR_y2jP58GthOYKk0YG=6gNxKHxVUJbG7z2CoQ@mail.gmail.com> (raw)
In-Reply-To: <AM6PR03MB51704629E50F6280A52D9FAFE4F10@AM6PR03MB5170.eurprd03.prod.outlook.com>
On Fri, Dec 4, 2020 at 12:30 PM Bernd Edlinger
<bernd.edlinger@hotmail.de> wrote:
>>
> > perf_event_open (exec_update_mutex -> ovl_i_mutex)
Side note: this one looks like it should be easy to fix.
Is there any real reason why exec_update_mutex is actually gotten that
early, and held for that long in the perf event code?
I _think_ we could move the ptrace check to be much later, to _just_ before that
* This is the point on no return; we cannot fail hereafter.
point in the perf event install chain..
I don't think it needs to be moved down even that much, I think it
would be sufficient to move it down below the "perf_event_alloc()",
but I didn't check very much.
The fact that create_local_trace_uprobe() can end up going into a
lookup of an OVL filesystem path smells kind of odd to me to begin
with, but I didn't look at the whole thing.
PeterZ, is there something I'm missing?
Linus
next prev parent reply other threads:[~2020-12-04 20:50 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-03 20:09 [PATCH 0/3] exec: Transform exec_update_mutex into a rw_semaphore Eric W. Biederman
2020-12-03 20:10 ` [PATCH 1/3] rwsem: Implement down_read_killable_nested Eric W. Biederman
2020-12-04 1:58 ` Waiman Long
2020-12-09 18:38 ` [tip: locking/core] " tip-bot2 for Eric W. Biederman
2020-12-03 20:11 ` [PATCH 2/3] rwsem: Implement down_read_interruptible Eric W. Biederman
2020-12-04 1:59 ` Waiman Long
2020-12-07 9:02 ` Peter Zijlstra
2020-12-07 15:33 ` Waiman Long
2020-12-07 16:58 ` David Laight
2020-12-07 19:02 ` Waiman Long
2020-12-08 9:12 ` David Laight
2020-12-08 12:32 ` Peter Zijlstra
2020-12-08 13:13 ` David Laight
2020-12-08 15:34 ` Waiman Long
2020-12-08 16:23 ` David Laight
2020-12-07 15:56 ` Eric W. Biederman
2020-12-08 14:52 ` Peter Zijlstra
2020-12-08 18:27 ` Eric W. Biederman
2020-12-09 18:36 ` Peter Zijlstra
2020-12-10 19:33 ` Eric W. Biederman
2020-12-11 8:16 ` Peter Zijlstra
2020-12-09 18:38 ` [tip: locking/core] locking/rwsem: Introduce rwsem_write_trylock() tip-bot2 for Peter Zijlstra
2020-12-09 18:38 ` [tip: locking/core] locking/rwsem: Fold __down_{read,write}*() tip-bot2 for Peter Zijlstra
2020-12-09 18:38 ` [tip: locking/core] locking/rwsem: Better collate rwsem_read_trylock() tip-bot2 for Peter Zijlstra
2020-12-09 18:38 ` [tip: locking/core] rwsem: Implement down_read_interruptible tip-bot2 for Eric W. Biederman
2020-12-03 20:12 ` [PATCH 3/3] exec: Transform exec_update_mutex into a rw_semaphore Eric W. Biederman
2020-12-04 16:08 ` Bernd Edlinger
2020-12-04 17:21 ` Linus Torvalds
2020-12-04 19:34 ` Eric W. Biederman
2020-12-04 20:10 ` Linus Torvalds
2020-12-04 20:30 ` Bernd Edlinger
2020-12-04 20:48 ` Linus Torvalds [this message]
2020-12-04 21:48 ` Davidlohr Bueso
2020-12-05 18:05 ` Eric W. Biederman
2020-12-07 9:15 ` Peter Zijlstra
2020-12-07 9:09 ` Peter Zijlstra
2020-12-07 18:40 ` Linus Torvalds
2020-12-08 8:34 ` [PATCH] perf: Break deadlock involving exec_update_mutex Peter Zijlstra
2020-12-08 18:37 ` Linus Torvalds
2020-12-10 18:38 ` Davidlohr Bueso
2020-12-10 19:40 ` Eric W. Biederman
2020-12-05 17:43 ` [PATCH 3/3] exec: Transform exec_update_mutex into a rw_semaphore Eric W. Biederman
2020-12-04 17:39 ` Eric W. Biederman
2020-12-03 22:42 ` [PATCH 0/3] " Linus Torvalds
2020-12-04 1:56 ` Waiman Long
2020-12-04 4:54 ` Davidlohr Bueso
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