From: Eric Biggers <ebiggers@kernel.org>
To: Hillf Danton <hdanton@sina.com>
Cc: syzbot <syzbot+7a0d9d0b26efefe61780@syzkaller.appspotmail.com>,
akpm@linux-foundation.org, arve@android.com,
christian@brauner.io, devel@driverdev.osuosl.org,
gregkh@linuxfoundation.org, hughd@google.com,
joel@joelfernandes.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, maco@android.com,
syzkaller-bugs@googlegroups.com, tkjos@android.com,
Markus Elfring <Markus.Elfring@web.de>
Subject: Re: possible deadlock in shmem_fallocate (4)
Date: Mon, 13 Jul 2020 20:41:11 -0700 [thread overview]
Message-ID: <20200714034111.GD1696@sol.localdomain> (raw)
In-Reply-To: <20200714033252.8748-1-hdanton@sina.com>
On Tue, Jul 14, 2020 at 11:32:52AM +0800, Hillf Danton wrote:
>
> Add FALLOC_FL_NOBLOCK and on the shmem side try to lock inode upon the
> new flag. And the overall upside is to keep the current gfp either in
> the khugepaged context or not.
>
> --- a/include/uapi/linux/falloc.h
> +++ b/include/uapi/linux/falloc.h
> @@ -77,4 +77,6 @@
> */
> #define FALLOC_FL_UNSHARE_RANGE 0x40
>
> +#define FALLOC_FL_NOBLOCK 0x80
> +
You can't add a new UAPI flag to fix a kernel-internal problem like this.
- Eric
next prev parent reply other threads:[~2020-07-14 3:41 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-26 21:25 possible deadlock in shmem_fallocate (4) syzbot
2020-03-07 21:43 ` [ashmem] " Eric Biggers
2020-07-14 0:32 ` syzbot
2020-07-14 3:07 ` syzbot
[not found] ` <20200714033252.8748-1-hdanton@sina.com>
2020-07-14 3:41 ` Eric Biggers [this message]
[not found] ` <20200714053205.15240-1-hdanton@sina.com>
2020-07-14 8:26 ` Michal Hocko
[not found] ` <20200714140859.15156-1-hdanton@sina.com>
2020-07-14 14:18 ` Michal Hocko
2020-07-14 15:46 ` Todd Kjos
2020-07-14 16:41 ` Suren Baghdasaryan
2020-07-14 17:32 ` Suren Baghdasaryan
2020-07-15 6:36 ` Michal Hocko
2020-07-16 2:49 ` Suren Baghdasaryan
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