From: David Sterba <dsterba@suse.cz>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Josef Bacik <josef@toxicpanda.com>,
David Sterba <dsterba@suse.com>,
Andreas Gruenbacher <agruenba@redhat.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Will Deacon <will@kernel.org>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 3/3] btrfs: Avoid live-lock in search_ioctl() on hardware with sub-page faults
Date: Fri, 26 Nov 2021 17:42:52 +0100 [thread overview]
Message-ID: <20211126164252.GB28560@suse.cz> (raw)
In-Reply-To: <20211124192024.2408218-4-catalin.marinas@arm.com>
On Wed, Nov 24, 2021 at 07:20:24PM +0000, Catalin Marinas wrote:
> Commit a48b73eca4ce ("btrfs: fix potential deadlock in the search
> ioctl") addressed a lockdep warning by pre-faulting the user pages and
> attempting the copy_to_user_nofault() in an infinite loop. On
> architectures like arm64 with MTE, an access may fault within a page at
> a location different from what fault_in_writeable() probed. Since the
> sk_offset is rewound to the previous struct btrfs_ioctl_search_header
> boundary, there is no guaranteed forward progress and search_ioctl() may
> live-lock.
>
> Use fault_in_exact_writeable() instead which probes the entire user
> buffer for faults at sub-page granularity.
>
> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
> Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: David Sterba <dsterba@suse.com>
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next prev parent reply other threads:[~2021-11-26 16:44 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-24 19:20 [PATCH 0/3] Avoid live-lock in fault-in+uaccess loops with sub-page faults Catalin Marinas
2021-11-24 19:20 ` [PATCH 1/3] mm: Introduce fault_in_exact_writeable() to probe for " Catalin Marinas
2021-11-24 19:20 ` [PATCH 2/3] arm64: Add support for sub-page faults user probing Catalin Marinas
2021-11-24 19:20 ` [PATCH 3/3] btrfs: Avoid live-lock in search_ioctl() on hardware with sub-page faults Catalin Marinas
2021-11-24 20:03 ` Matthew Wilcox
2021-11-24 20:37 ` Catalin Marinas
2021-11-25 22:25 ` Andreas Gruenbacher
2021-11-25 22:42 ` Catalin Marinas
2021-11-26 22:29 ` Andreas Gruenbacher
2021-11-26 22:57 ` Catalin Marinas
2021-11-27 3:52 ` Andreas Gruenbacher
2021-11-27 14:33 ` Catalin Marinas
2021-11-27 12:39 ` Andreas Gruenbacher
2021-11-27 15:21 ` Catalin Marinas
2021-11-27 18:05 ` Andreas Gruenbacher
2021-11-29 12:16 ` Catalin Marinas
2021-11-29 13:33 ` Andreas Gruenbacher
2021-11-29 15:36 ` Catalin Marinas
2021-11-29 18:40 ` Linus Torvalds
2021-11-29 19:31 ` Andreas Gruenbacher
2021-11-29 20:56 ` Catalin Marinas
2021-11-29 21:53 ` Linus Torvalds
2021-11-29 23:12 ` Catalin Marinas
2021-11-29 13:52 ` Catalin Marinas
2021-11-24 23:00 ` Linus Torvalds
2021-11-25 11:10 ` Catalin Marinas
2021-11-25 18:13 ` Linus Torvalds
2021-11-25 20:43 ` Catalin Marinas
2021-11-25 21:02 ` Matthew Wilcox
2021-11-25 21:29 ` Catalin Marinas
2021-11-25 21:40 ` Andreas Gruenbacher
2021-11-26 16:42 ` David Sterba [this message]
2021-11-24 21:36 ` [PATCH 0/3] Avoid live-lock in fault-in+uaccess loops " Andrew Morton
2021-11-24 22:31 ` Catalin Marinas
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