From: Johan Hovold <johan@kernel.org>
To: kernel test robot <oliver.sang@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Joel Stanley <joel@jms.id.au>, Andrew Jeffery <andrew@aj.id.au>,
Andy Gross <agross@kernel.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
LKML <linux-kernel@vger.kernel.org>,
lkp@lists.01.org, lkp@intel.com
Subject: Re: [serial] 75f4e830fa: WARNING:inconsistent_lock_state
Date: Mon, 12 Jul 2021 16:39:37 +0200 [thread overview]
Message-ID: <YOxUKTHlLa8ViPUh@hovoldconsulting.com> (raw)
In-Reply-To: <20210712143414.GB13620@xsang-OptiPlex-9020>
On Mon, Jul 12, 2021 at 10:34:14PM +0800, kernel test robot wrote:
> Greeting,
>
> FYI, we noticed the following commit (built with clang-13):
>
> commit: 75f4e830fa9c47637054a3b7201765f2a314bda2 ("serial: do not restore interrupt state in sysrq helper")
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
> [ 208.007748] Possible unsafe locking scenario:
> [ 208.007748]
> [ 208.008411] CPU0
> [ 208.008682] ----
> [ 208.008955] lock(&port_lock_key);
> [ 208.009398] <Interrupt>
> [ 208.009703] lock(&port_lock_key);
> [ 208.010122]
> [ 208.010122] *** DEADLOCK ***
> [ 208.010122]
> [ 208.010790] 1 lock held by rngd/341:
> [ 208.011190] #0: ffff9e8ec0e6fd80 ((&up->timer)){+.-.}-{0:0}, at: call_timer_fn+0x48/0x2eb
> [ 208.012101]
> [ 208.012101] stack backtrace:
> [ 208.012579] CPU: 1 PID: 341 Comm: rngd Not tainted 5.12.0-rc6+ #1
> [ 208.013253] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
> [ 208.014128] Call Trace:
> [ 208.014406] dump_stack+0x8b/0xdc
> [ 208.014776] mark_lock_irq+0x5b9/0x6f3
> [ 208.015175] ? stack_trace_save+0x50/0x6e
> [ 208.015615] ? save_trace+0x4d/0x30d
> [ 208.016001] mark_lock+0x121/0x1a3
> [ 208.016378] __lock_acquire+0x645/0x2ca8
> [ 208.016807] ? lockdep_unlock+0x8f/0x113
> [ 208.017256] ? __lock_acquire+0x133e/0x2ca8
> [ 208.017707] ? lock_is_held_type+0x102/0x15d
> [ 208.018175] lock_acquire+0x1a1/0x2ab
> [ 208.018590] ? serial8250_handle_irq+0x1a/0xdb
> [ 208.019072] ? serial8250_handle_irq+0x1a/0xdb
> [ 208.019560] _raw_spin_lock+0x34/0x67
> [ 208.019956] ? serial8250_handle_irq+0x1a/0xdb
> [ 208.020444] ? univ8250_console_match+0x130/0x130
> [ 208.020951] serial8250_handle_irq+0x1a/0xdb
> [ 208.021444] ? univ8250_console_match+0x130/0x130
> [ 208.021950] serial8250_default_handle_irq+0x3b/0x4a
Bah, the interrupt handler can end up being called by a timer callback
in some setups.
I'll prepare a patch.
> [ 208.022492] serial8250_timeout+0x17/0x42
> [ 208.022933] call_timer_fn+0x145/0x2eb
> [ 208.023349] ? univ8250_console_match+0x130/0x130
> [ 208.023854] run_timer_softirq+0x281/0x33e
> [ 208.024308] __do_softirq+0x28f/0x50b
> [ 208.024716] ? asm_sysvec_apic_timer_interrupt+0xa/0x20
> [ 208.025389] __irq_exit_rcu+0xb7/0xbe
> [ 208.025817] irq_exit_rcu+0x5/0x19
> [ 208.026211] sysvec_apic_timer_interrupt+0x3e/0xa3
> [ 208.026781] asm_sysvec_apic_timer_interrupt+0x12/0x20
Thanks for the report.
Johan
prev parent reply other threads:[~2021-07-12 14:39 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-12 14:34 kernel test robot
2021-07-12 14:39 ` Johan Hovold [this message]
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