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From: "Ahmed S. Darwish" <darwish.07@gmail.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lennart Poettering <mzxreary@0pointer.de>,
	"Theodore Y. Ts'o" <tytso@mit.edu>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	"Alexander E. Patrakov" <patrakov@gmail.com>,
	Michael Kerrisk <mtk.manpages@gmail.com>,
	lkml <linux-kernel@vger.kernel.org>,
	linux-ext4@vger.kernel.org, linux-man@vger.kernel.org
Subject: [PATCH RFC v4 0/1] random: WARN on large getrandom() waits and introduce getrandom2()
Date: Wed, 18 Sep 2019 23:15:03 +0200	[thread overview]
Message-ID: <20190918211503.GA1808@darwi-home-pc> (raw)
In-Reply-To: <CAHk-=wgg2T=3KxrO-BY3nHJgMEyApjnO3cwbQb_0vxsn9qKN8Q@mail.gmail.com>

Hi,

This is an RFC, and it obviously needs much more testing beside the
"it boots" smoke test I've just did.

Interestingly though, on my current system, the triggered WARN()
**reliably** makes the system get un-stuck... I know this is a very
crude heuristic, but I would personally prefer it to the other
proposals that were mentioned in this jumbo thread.

If I get an OK from Linus on this, I'll send a polished v5: further
real testing, kernel-parameters.txt docs, a new getrandom_wait(7)
manpage as referenced in the WARN() message, and extensions to the
getrandom(2) manpage for new getrandom2().

The new getrandom2() system call is basically a summary of Linus',
Lennart's, and Willy's proposals. Please see the patch #1 commit log,
and the "Link:" section inside it, for a rationale.

@Lennart, since you obviously represent user-space here, any further
notes on the new system call?

thanks,

Ahmed S. Darwish (1):
  random: WARN on large getrandom() waits and introduce getrandom2()

 drivers/char/Kconfig        | 60 ++++++++++++++++++++++++--
 drivers/char/random.c       | 85 ++++++++++++++++++++++++++++++++-----
 include/uapi/linux/random.h | 20 +++++++--
 3 files changed, 148 insertions(+), 17 deletions(-)

--
http://darwish.chasingpointers.com

       reply	other threads:[~2019-09-18 21:15 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CAHk-=whW_AB0pZ0u6P9uVSWpqeb5t2NCX_sMpZNGy8shPDyDNg@mail.gmail.com>
     [not found] ` <CAHk-=wi_yXK5KSmRhgNRSmJSD55x+2-pRdZZPOT8Fm1B8w6jUw@mail.gmail.com>
     [not found]   ` <20190911173624.GI2740@mit.edu>
     [not found]     ` <20190912034421.GA2085@darwi-home-pc>
     [not found]       ` <20190912082530.GA27365@mit.edu>
     [not found]         ` <CAHk-=wjyH910+JRBdZf_Y9G54c1M=LBF8NKXB6vJcm9XjLnRfg@mail.gmail.com>
     [not found]           ` <20190914122500.GA1425@darwi-home-pc>
     [not found]             ` <008f17bc-102b-e762-a17c-e2766d48f515@gmail.com>
     [not found]               ` <20190915052242.GG19710@mit.edu>
     [not found]                 ` <CAHk-=wgg2T=3KxrO-BY3nHJgMEyApjnO3cwbQb_0vxsn9qKN8Q@mail.gmail.com>
2019-09-18 21:15                   ` Ahmed S. Darwish [this message]
2019-09-18 21:17                     ` [PATCH RFC v4 1/1] random: WARN on large getrandom() waits and introduce getrandom2() Ahmed S. Darwish
2019-09-18 23:57                       ` Linus Torvalds
2019-09-19 14:34                         ` Theodore Y. Ts'o
2019-09-19 15:20                           ` Linus Torvalds
2019-09-19 15:50                             ` Linus Torvalds
2019-09-20 13:13                               ` Theodore Y. Ts'o
2019-09-19 20:04                             ` Linus Torvalds
2019-09-19 20:45                               ` Alexander E. Patrakov
2019-09-19 21:47                                 ` Linus Torvalds
2019-09-19 22:23                                   ` Alexander E. Patrakov
2019-09-19 23:44                                     ` Alexander E. Patrakov
2019-09-20 13:16                                     ` Theodore Y. Ts'o
2019-09-23 11:55                               ` David Laight
2019-09-20 13:08                             ` Theodore Y. Ts'o
2019-09-20 13:46                         ` Ahmed S. Darwish
2019-09-20 14:33                           ` Andy Lutomirski
2019-09-20 16:29                             ` Linus Torvalds
2019-09-20 17:52                               ` Andy Lutomirski
2019-09-20 18:09                                 ` Linus Torvalds
2019-09-20 18:16                                   ` Willy Tarreau
2019-09-20 19:12                                   ` Andy Lutomirski
2019-09-20 19:51                                     ` Linus Torvalds
2019-09-20 20:11                                       ` Alexander E. Patrakov
2019-09-20 20:17                                       ` Matthew Garrett
2019-09-20 20:51                                       ` Andy Lutomirski
2019-09-20 22:44                                         ` Linus Torvalds
2019-09-20 23:30                                           ` Andy Lutomirski
2019-09-21  3:05                                             ` Willy Tarreau
2019-09-21  6:07                                   ` Florian Weimer
2019-09-23 18:33                                     ` Andy Lutomirski
2019-09-26 21:11                                       ` Ahmed S. Darwish
2019-09-20 18:12                                 ` Willy Tarreau
2019-09-20 19:22                                   ` Andy Lutomirski
2019-09-20 19:37                                     ` Willy Tarreau
2019-09-20 19:52                                       ` Andy Lutomirski
2019-09-20 20:02                                     ` Linus Torvalds
2019-09-20 18:15                                 ` Alexander E. Patrakov
2019-09-20 18:29                                   ` Andy Lutomirski
2019-09-20 17:26                           ` Willy Tarreau
2019-09-20 17:56                             ` Ahmed S. Darwish
2019-09-26 20:42                         ` [PATCH v5 0/1] random: getrandom(2): warn on large CRNG waits, introduce new flags Ahmed S. Darwish
2019-09-26 20:44                           ` [PATCH v5 1/1] " Ahmed S. Darwish
2019-09-26 21:39                             ` Andy Lutomirski
2019-09-28  9:30                               ` Ahmed S. Darwish

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