From: Andrea Arcangeli <aarcange@redhat.com>
To: Jiri Kosina <jikos@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
"Schaufler, Casey" <casey.schaufler@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
"Woodhouse, David" <dwmw@amazon.co.uk>,
Oleg Nesterov <oleg@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>
Subject: Re: [PATCH v3 1/3] ptrace: Provide ___ptrace_may_access() that can be applied on arbitrary tasks
Date: Wed, 5 Sep 2018 14:40:18 -0400 [thread overview]
Message-ID: <20180905184018.GC11625@redhat.com> (raw)
In-Reply-To: <nycvar.YFH.7.76.1809052026470.15880@cbobk.fhfr.pm>
On Wed, Sep 05, 2018 at 08:29:07PM +0200, Jiri Kosina wrote:
> (and no, my testing of the patch I sent on current tree didn't produce any
> hangs -- was there a reliable way to trigger it on 3.10?).
Only a very specific libvirt acceptance test found this after a while
and it wasn't a customer it was caught by QA. The reporter said it
wasn't sure about how to reproduce this issue either, it happened once
in a while the backtrace was still enough to fix it for sure and then
it never happened again.
It's not because of virt but probably because of selinux+audit. This
is precisely why I thought once you enter LSM from the scheduler
atomic path the trouble starts as each LSM implementation of those
calls may crash or not crash.
Perhaps you didn't sandbox KVM inside selinux by default?
This is the lockup the patch I posted fixed for 3.10.
[ 1838.621010] Kernel panic - not syncing: Watchdog detected hard LOCKUP on cpu 6
[ 1838.629070] CPU: 6 PID: 0 Comm: swapper/6 Not tainted 3.10.0-327.62.4.el7.x86_64 #1
[ 1838.637610] Hardware name: Dell Inc. PowerEdge R430/0CN7X8, BIOS 2.4.2 01/09/2017
[ 1838.645954] Call Trace:
[ 1838.648680] <NMI> [<ffffffff8163a05d>] dump_stack+0x19/0x1b
[ 1838.655113] [<ffffffff816338d0>] panic+0xd8/0x1e7
[ 1838.660460] [<ffffffff8111e960>] ? restart_watchdog_hrtimer+0x50/0x50
[ 1838.667742] [<ffffffff8111ea22>] watchdog_overflow_callback+0xc2/0xd0
[ 1838.675024] [<ffffffff81162211>] __perf_event_overflow+0xa1/0x250
[ 1838.681920] [<ffffffff81162ce4>] perf_event_overflow+0x14/0x20
[ 1838.688526] [<ffffffff810337c8>] intel_pmu_handle_irq+0x1e8/0x470
[ 1838.695423] [<ffffffff812f83cc>] ? ioremap_page_range+0x24c/0x330
[ 1838.702320] [<ffffffff811a9031>] ? unmap_kernel_range_noflush+0x11/0x20
[ 1838.709797] [<ffffffff813997f4>] ? ghes_copy_tofrom_phys+0x124/0x210
[ 1838.716984] [<ffffffff81399980>] ? ghes_read_estatus+0xa0/0x190
[ 1838.723687] [<ffffffff816444bb>] perf_event_nmi_handler+0x2b/0x50
[ 1838.730582] [<ffffffff81643c09>] nmi_handle.isra.0+0x69/0xb0
[ 1838.736992] [<ffffffff81643db9>] do_nmi+0x169/0x340
[ 1838.742532] [<ffffffff81642ff9>] end_repeat_nmi+0x1e/0x7e
[ 1838.748653] [<ffffffff81641bbd>] ? _raw_spin_lock_irqsave+0x3d/0x60
[ 1838.755742] [<ffffffff81641bbd>] ? _raw_spin_lock_irqsave+0x3d/0x60
[ 1838.762831] [<ffffffff81641bbd>] ? _raw_spin_lock_irqsave+0x3d/0x60
[ 1838.769917] <<EOE>> [<ffffffff816391e5>] avc_compute_av+0x126/0x1b5
[ 1838.777125] [<ffffffff810b842e>] ? walk_tg_tree_from+0xbe/0x110
[ 1838.783828] [<ffffffff8128b9c4>] avc_has_perm_noaudit+0xc4/0x110
[ 1838.790628] [<ffffffff8128f1fb>] cred_has_capability+0x6b/0x120
[ 1838.797331] [<ffffffff810db71c>] ? ktime_get+0x4c/0xd0
[ 1838.803160] [<ffffffff810e167b>] ? clockevents_program_event+0x6b/0xf0
[ 1838.810532] [<ffffffff8128f2de>] selinux_capable+0x2e/0x40
[ 1838.816748] [<ffffffff81288f65>] security_capable_noaudit+0x15/0x20
[ 1838.823829] [<ffffffff8108b975>] has_ns_capability_noaudit+0x15/0x20
[ 1838.831014] [<ffffffff8108bc55>] ptrace_has_cap+0x35/0x40
[ 1838.837126] [<ffffffff8108c717>] ___ptrace_may_access+0xa7/0x1e0
[ 1838.843925] [<ffffffff8163f0ae>] __schedule+0x26e/0xa00
[ 1838.849855] [<ffffffff81640949>] schedule_preempt_disabled+0x29/0x70
[ 1838.857041] [<ffffffff810d9324>] cpu_startup_entry+0x184/0x290
[ 1838.863637] [<ffffffff8104891a>] start_secondary+0x1da/0x250
next prev parent reply other threads:[~2018-09-05 18:40 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-31 20:56 [PATCH] x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation Jiri Kosina
2018-09-03 8:51 ` Jiri Kosina
2018-09-03 12:45 ` [PATCH v2 0/3] Harden spectrev2 userspace-userspace protection Jiri Kosina
2018-09-04 14:23 ` [PATCH v3 " Jiri Kosina
2018-09-04 14:40 ` [PATCH v3 1/3] ptrace: Provide ___ptrace_may_access() that can be applied on arbitrary tasks Jiri Kosina
2018-09-04 16:13 ` Thomas Gleixner
2018-09-04 16:21 ` Thomas Gleixner
2018-09-04 17:26 ` Tim Chen
2018-09-04 17:35 ` Jiri Kosina
2018-09-04 18:10 ` Schaufler, Casey
2018-09-04 18:48 ` Jiri Kosina
2018-09-04 23:26 ` Tim Chen
2018-09-05 6:22 ` Jiri Kosina
2018-09-05 15:58 ` Andi Kleen
2018-09-05 18:04 ` Andrea Arcangeli
2018-09-05 18:29 ` Jiri Kosina
2018-09-05 18:40 ` Andrea Arcangeli [this message]
2018-09-05 18:42 ` Jiri Kosina
2018-09-05 19:03 ` Peter Zijlstra
2018-09-05 19:27 ` Schaufler, Casey
2018-09-05 20:02 ` Jiri Kosina
2018-09-05 18:26 ` Thomas Gleixner
2018-09-05 18:35 ` Jiri Kosina
2018-09-04 23:37 ` Andrea Arcangeli
2018-09-05 1:00 ` Schaufler, Casey
2018-09-05 2:38 ` Andrea Arcangeli
2018-09-05 8:00 ` Peter Zijlstra
2018-09-05 15:37 ` Schaufler, Casey
2018-09-05 7:51 ` Peter Zijlstra
2018-09-04 14:42 ` [PATCH v3 2/3] x86/speculation: apply IBPB more strictly to avoid cross-process data leak Jiri Kosina
2018-09-04 16:18 ` Thomas Gleixner
2018-09-05 7:59 ` Peter Zijlstra
2018-09-05 8:02 ` Jiri Kosina
2018-09-05 9:40 ` Peter Zijlstra
2018-09-05 7:52 ` Peter Zijlstra
2018-09-05 7:55 ` Jiri Kosina
2018-09-04 14:42 ` [PATCH v3 3/3] x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation Jiri Kosina
-- strict thread matches above, loose matches on Subject: below --
2018-09-04 14:24 [PATCH v3 1/3] ptrace: Provide ___ptrace_may_access() that can be applied on arbitrary tasks Jiri Kosina
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180905184018.GC11625@redhat.com \
--to=aarcange@redhat.com \
--cc=ak@linux.intel.com \
--cc=casey.schaufler@intel.com \
--cc=dwmw@amazon.co.uk \
--cc=jikos@kernel.org \
--cc=jpoimboe@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=oleg@redhat.com \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
--cc=tim.c.chen@linux.intel.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox