From: Naresh Kamboju <naresh.kamboju@linaro.org>
To: Peter Xu <peterx@redhat.com>
Cc: open list <linux-kernel@vger.kernel.org>,
"open list:KERNEL SELFTEST FRAMEWORK"
<linux-kselftest@vger.kernel.org>, linux-mm <linux-mm@kvack.org>,
lkft-triage@lists.linaro.org, Shuah Khan <shuah@kernel.org>,
Anders Roxell <anders.roxell@linaro.org>,
Christophe Leroy <christophe.leroy@c-s.fr>,
Andrew Morton <akpm@linux-foundation.org>,
Leonardo Bras <leonardo@linux.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Arnd Bergmann <arnd@arndb.de>,
Jules Irenge <jbi.octave@gmail.com>,
"Huang, Ying" <ying.huang@intel.com>,
Pankaj Gupta <pankaj.gupta.linux@gmail.com>,
Rik van Riel <riel@surriel.com>, Hugh Dickins <hughd@google.com>,
Minchan Kim <minchan@kernel.org>, Mel Gorman <mgorman@suse.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Mateusz Nosek <mateusznosek0@gmail.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Kees Cook <keescook@chromium.org>,
Vlastimil Babka <vbabka@suse.cz>, Hillf Danton <hdanton@sina.com>
Subject: Re: i386: selftests: vm: compaction_test: BUG: kernel NULL pointer dereference, address: 00000000
Date: Mon, 13 Apr 2020 16:51:25 +0530 [thread overview]
Message-ID: <CA+G9fYvARTCKjbfHYEbfOjtn_s7desuAToOF4g+Z_fztzZ-myw@mail.gmail.com> (raw)
In-Reply-To: <20200412214150.GB38470@xz-x1>
On Mon, 13 Apr 2020 at 03:12, Peter Xu <peterx@redhat.com> wrote:
> And since this one is very easy to reproduce, I finally noticed that
> we have wrongly enabled uffd-wp on x86_32, which is definely not going
> to work... Because we'll use bit 2 of swap entry assuming that's the
> uffd-wp bit, while that's part of swp offset on 32bit systems.
>
> Naresh, could you try whether below change fixes the issue for you?
>
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 8d078642b4be..7ac524d1316e 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -149,7 +149,7 @@ config X86
> select HAVE_ARCH_TRACEHOOK
> select HAVE_ARCH_TRANSPARENT_HUGEPAGE
> select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
> - select HAVE_ARCH_USERFAULTFD_WP if USERFAULTFD
> + select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD
> select HAVE_ARCH_VMAP_STACK if X86_64
> select HAVE_ARCH_WITHIN_STACK_FRAMES
> select HAVE_ASM_MODVERSIONS
>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
The above patch tested and did not notice the crash.
+ cd /opt/kselftests/default-in-kernel/vm/
+ ./compaction_test
No of huge pages allocated = 297
+ ./compaction_test
[ 46.059785] kauditd_printk_skb: 15 callbacks suppressed
[ 46.059786] audit: type=1334 audit(1586776582.927:25): prog-id=17 op=UNLOAD
[ 46.071997] audit: type=1334 audit(1586776582.927:26): prog-id=16 op=UNLOAD
No of huge pages allocated = 160
Full test log,
https://lkft.validation.linaro.org/scheduler/job/1362495#L1308
Build artifacts.
https://builds.tuxbuild.com/w0ol7cCsGan0wzPp7bNqkg/
- Naresh
next prev parent reply other threads:[~2020-04-13 11:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-12 6:54 Naresh Kamboju
2020-04-12 21:41 ` Peter Xu
2020-04-13 11:21 ` Naresh Kamboju [this message]
2020-04-13 14:14 ` Peter Xu
2020-04-13 17:53 ` Dave Hansen
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