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From: Alexey Gladkov <legion@kernel.org>
To: Jordan Glover <Golden_Miller83@protonmail.ch>
Cc: ebiederm@xmission.com, LKML <linux-kernel@vger.kernel.org>,
	linux-mm@kvack.org, containers@lists.linux-foundation.org,
	Yu Zhao <yuzhao@google.com>
Subject: Re: linux 5.14.3: free_user_ns causes NULL pointer dereference
Date: Thu, 30 Sep 2021 15:06:40 +0200	[thread overview]
Message-ID: <20210930130640.wudkpmn3cmah2cjz@example.org> (raw)
In-Reply-To: <hPgvCJ2KbKeauk78uWJEsuKJ5VfMqknPJ_oyOZe6M78-6eG7qnj0t0UKC-joPVowo_nOikIsEWP-ZDioARfI-Cl6zrHjCHPJST3drpi5ALE=@protonmail.ch>

On Wed, Sep 29, 2021 at 09:39:06PM +0000, Jordan Glover wrote:
> > I'm still investigating, but I would like to rule out one option.
> >
> > Could you check out the patch?
> 
> 
> Thx, I added it to my kernel and will report in few days.
> Does this patch try to fix the issue or make it easier to track?

I suspect the error is caused by a race between allow_ucounts() and
put_ucounts(). I think this patch could solve the problem.

-- 
Rgrds, legion


  reply	other threads:[~2021-09-30 13:07 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-15 19:49 linux 5.14.3: free_user_ns causes NULL pointer dereference Jordan Glover
2021-09-15 21:02 ` Eric W. Biederman
2021-09-15 22:42   ` Jordan Glover
2021-09-15 23:44     ` Yu Zhao
2021-09-17 16:15       ` Eric W. Biederman
2021-09-17 18:45         ` Yu Zhao
2021-09-15 23:47     ` Jordan Glover
2021-09-16 17:30       ` Eric W. Biederman
2021-09-16 19:14         ` Alexey Gladkov
2021-09-28 13:40         ` Jordan Glover
2021-09-29 17:36           ` Alexey Gladkov
2021-09-29 21:39             ` Jordan Glover
2021-09-30 13:06               ` Alexey Gladkov [this message]
2021-09-30 22:27                 ` Yu Zhao
2021-10-04 17:10                   ` Eric W. Biederman
2021-10-04 17:19                     ` Eric W. Biederman
2021-10-04 21:34                       ` Yu Zhao
2021-10-11 13:39                       ` Alexey Gladkov
     [not found]                       ` <ccbccf82-dc50-00b2-1cfd-3da5e2c81dbf@infomedia.dk>
2021-10-12 17:31                         ` Eric W. Biederman
2021-10-15 22:10                         ` [CFT][PATCH] ucounts: Fix signal ucount refcounting Eric W. Biederman
2021-10-15 23:09                           ` Alexey Gladkov
2021-10-16 17:34                             ` Eric W. Biederman
2021-10-17 19:35                               ` Yu Zhao
2021-10-18 15:35                                 ` Eric W. Biederman
2021-10-17 16:47                           ` Rune Kleveland
2021-10-18  6:25                             ` Yu Zhao
2021-10-18 10:31                               ` Jordan Glover
2021-10-18 16:06                           ` [PATCH v2] " Eric W. Biederman
2021-10-18 17:21                             ` [PATCH 0/3] ucounts: misc fixes Eric W. Biederman
2021-10-18 17:23                               ` [PATCH 1/3] ucounts: Pair inc_rlimit_ucounts with dec_rlimit_ucoutns in commit_creds Eric W. Biederman
2021-10-18 17:23                               ` [PATCH 2/3] ucounts: Proper error handling in set_cred_ucounts Eric W. Biederman
2021-10-18 17:24                               ` [PATCH 3/3] ucounts: Move get_ucounts from cred_alloc_blank to key_change_session_keyring Eric W. Biederman
2021-10-18 17:54                               ` [PATCH 0/4] ucounts: misc cleanups Eric W. Biederman
2021-10-18 17:55                                 ` [PATCH 1/4] ucounts: In set_cred_ucounts assume new->ucounts is non-NULL Eric W. Biederman
2021-10-18 17:56                                 ` [PATCH 2/4] ucounts: Remove unnecessary test for NULL ucount in get_ucounts Eric W. Biederman
2021-10-18 17:56                                 ` [PATCH 3/4] ucounts: Add get_ucounts_or_wrap for clarity Eric W. Biederman
2021-10-18 17:57                                 ` [PATCH 4/4] ucounts: Use atomic_long_sub_return " Eric W. Biederman
2021-10-18 22:29                                 ` [PATCH 0/4] ucounts: misc cleanups Yu Zhao
2021-10-18 22:28                               ` [PATCH 0/3] ucounts: misc fixes Yu Zhao
2021-10-18 22:26                             ` [PATCH v2] ucounts: Fix signal ucount refcounting Yu Zhao
     [not found]                         ` <20211016020833.1538-1-hdanton@sina.com>
2021-10-16 18:00                           ` [CFT][PATCH] " Eric W. Biederman
     [not found]                   ` <20211006021219.2010-1-hdanton@sina.com>
2021-10-06  6:22                     ` linux 5.14.3: free_user_ns causes NULL pointer dereference Yu Zhao
2021-10-07 13:28                     ` Jordan Glover
2021-10-03 19:37             ` Jordan Glover
2021-10-20  7:39 Antoine Martin

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