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From: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: "debian-powerpc@lists.debian.org"
	<debian-powerpc@lists.debian.org>,
	linuxppc-dev@lists.ozlabs.org
Subject: Re: Linux kernel: powerpc: KVM guest can trigger host crash on Power8
Date: Mon, 1 Nov 2021 18:20:49 +0100	[thread overview]
Message-ID: <fd7dbee5-464e-1063-d51c-85f2f2429019@physik.fu-berlin.de> (raw)
In-Reply-To: <8759057e-170c-3972-997f-a63d88b0e94c@physik.fu-berlin.de>

Hi Michael!

On 11/1/21 08:37, John Paul Adrian Glaubitz wrote:
> I made another experiment and upgraded the host to 5.15-rc7 which contains your
> fixes and made the guests build gcc-10. Interestingly, this time, the gcc-10
> build crashed the guest but didn't manage to crash the host. I will update the
> guest to 5.15-rc7 now as well and see how that goes.

OK, so I'm definitely able to crash the 5.15 kernel as well:

[57031.404944] watchdog: BUG: soft lockup - CPU#24 stuck for 14957s! [migration/24:14]
[57035.420898] watchdog: BUG: soft lockup - CPU#48 stuck for 14961s! [CPU 17/KVM:1815]
[57047.456761] watchdog: BUG: soft lockup - CPU#152 stuck for 14841s! [CPU 13/KVM:1811]
[57055.404670] watchdog: BUG: soft lockup - CPU#24 stuck for 14979s! [migration/24:14]
[57059.420624] watchdog: BUG: soft lockup - CPU#48 stuck for 14983s! [CPU 17/KVM:1815]
[57064.064573] rcu: INFO: rcu_sched self-detected stall on CPU
[57064.064584] rcu:     48-....: (3338577 ticks this GP) idle=9f3/1/0x4000000000000002 softirq=77540/77540 fqs=15421 
[57064.064598] rcu: rcu_sched kthread timer wakeup didn't happen for 3988041 jiffies! g125265 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x200
[57064.064606] rcu:     Possible timer handling issue on cpu=136 timer-softirq=313650
[57064.064611] rcu: rcu_sched kthread starved for 3988042 jiffies! g125265 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x200 ->cpu=136
[57064.064618] rcu:     Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior.
[57064.064624] rcu: RCU grace-period kthread stack dump:
[57064.064665] rcu: Stack dump where RCU GP kthread last ran:
[57071.456487] watchdog: BUG: soft lockup - CPU#152 stuck for 14863s! [CPU 13/KVM:1811]
[57079.404396] watchdog: BUG: soft lockup - CPU#24 stuck for 15002s! [migration/24:14]

And the gcc-10 testsuite is able to trigger the crash very reliably.

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz@debian.org
`. `'   Freie Universitaet Berlin - glaubitz@physik.fu-berlin.de
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913


  reply	other threads:[~2021-11-01 17:21 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-25 11:18 Linux kernel: powerpc: KVM guest can trigger host crash on Power8 Michael Ellerman
2021-10-26  8:48 ` John Paul Adrian Glaubitz
2021-10-27  5:29   ` Nicholas Piggin
2021-10-27  5:30   ` Michael Ellerman
2021-10-27 10:03     ` John Paul Adrian Glaubitz
2021-10-27 11:06       ` Michael Ellerman
2021-10-27 11:09         ` John Paul Adrian Glaubitz
2021-10-28  6:39           ` Michael Ellerman
2021-10-28 11:20             ` John Paul Adrian Glaubitz
2021-10-28 14:05               ` John Paul Adrian Glaubitz
2021-10-28 14:15                 ` John Paul Adrian Glaubitz
2021-11-01 17:36                   ` Michal Suchánek
2021-10-29  0:41                 ` Nicholas Piggin
2021-10-29 12:33                   ` John Paul Adrian Glaubitz
2021-11-01 17:43                     ` Michal Suchánek
2021-10-30  7:19             ` John Paul Adrian Glaubitz
2021-11-01  6:53               ` Michael Ellerman
2021-11-01  7:37                 ` John Paul Adrian Glaubitz
2021-11-01 17:20                   ` John Paul Adrian Glaubitz [this message]
2022-01-04 13:00                 ` John Paul Adrian Glaubitz
2022-01-06 10:58                   ` Michael Ellerman
2022-01-07 11:20                     ` John Paul Adrian Glaubitz
2022-01-09 22:17                       ` John Paul Adrian Glaubitz
2022-01-13  0:17                         ` John Paul Adrian Glaubitz
2022-01-26 20:21                           ` John Paul Adrian Glaubitz
2022-01-27 15:50                             ` Mike
2021-10-28 13:52   ` John Paul Adrian Glaubitz
2021-10-28 14:00     ` John Paul Adrian Glaubitz
2021-10-28  3:58 ` [oss-security] " Salvatore Bonaccorso

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