From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Rocco Yue <rocco.yue@mediatek.com>
Cc: "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Matthias Brugger <matthias.bgg@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Masahiro Yamada <masahiroy@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
Peter Enderborg <peter.enderborg@sony.com>,
Thomas Gleixner <tglx@linutronix.de>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Vitor Massaru Iha <vitor@massaru.org>,
Sedat Dilek <sedat.dilek@gmail.com>,
Wei Yang <richard.weiyang@gmail.com>,
Cong Wang <cong.wang@bytedance.com>, Di Zhu <zhudi21@huawei.com>,
Stephen Hemminger <stephen@networkplumber.org>,
Francis Laniel <laniel_francis@privacyrequired.com>,
Roopa Prabhu <roopa@cumulusnetworks.com>,
Andrii Nakryiko <andrii@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
netdev <netdev@vger.kernel.org>,
linux-arm Mailing List <linux-arm-kernel@lists.infradead.org>,
"moderated list:ARM/Mediatek SoC support"
<linux-mediatek@lists.infradead.org>,
wsd_upsream@mediatek.com
Subject: Re: [PATCH][v2] rtnetlink: add rtnl_lock debug log
Date: Sun, 9 May 2021 12:42:08 +0300 [thread overview]
Message-ID: <CAHp75VftbW7pgkfrSB6teKZO4EfGH9UWkhy1SAtijCLvKz8HTQ@mail.gmail.com> (raw)
In-Reply-To: <20210508085738.6296-1-rocco.yue@mediatek.com>
On Sat, May 8, 2021 at 12:11 PM Rocco Yue <rocco.yue@mediatek.com> wrote:
>
> We often encounter system hangs caused by certain process
> holding rtnl_lock for a long time. Even if there is a lock
> detection mechanism in Linux, it is a bit troublesome and
> affects the system performance. We hope to add a lightweight
> debugging mechanism for detecting rtnl_lock.
>
> Up to now, we have discovered and solved some potential bugs
> through this lightweight rtnl_lock debugging mechanism, which
> is helpful for us.
>
> When you say Y for RTNL_LOCK_DEBUG, then the kernel will detect
> if any function hold rtnl_lock too long and some key information
> will be printed out to help locate the problem.
>
> i.e: from the following logs, we can clearly know that the pid=2206
> RfxSender_4 process holds rtnl_lock for a long time, causing the
> system to hang. And we can also speculate that the delay operation
> may be performed in devinet_ioctl(), resulting in rtnl_lock was
> not released in time.
>
> <6>[ 40.191481][ C6] rtnetlink: -- rtnl_print_btrace start --
You don't seem to get it. It's a quite long trace for the commit
message. Do you need all those lines below? Why?
> <6>[ 40.191494][ C6] rtnetlink: RfxSender_4[2206][R] hold rtnl_lock
> more than 2 sec, start time: 38181400013
> <4>[ 40.191510][ C6] devinet_ioctl+0x1fc/0x75c
> <4>[ 40.191517][ C6] inet_ioctl+0xb8/0x1f8
> <4>[ 40.191527][ C6] sock_do_ioctl+0x70/0x2ac
> <4>[ 40.191533][ C6] sock_ioctl+0x5dc/0xa74
> <4>[ 40.191541][ C6] __arm64_sys_ioctl+0x178/0x1fc
> <4>[ 40.191548][ C6] el0_svc_common+0xc0/0x24c
> <4>[ 40.191555][ C6] el0_svc+0x28/0x88
> <4>[ 40.191560][ C6] el0_sync_handler+0x8c/0xf0
> <4>[ 40.191566][ C6] el0_sync+0x198/0x1c0
> <6>[ 40.191571][ C6] Call trace:
> <6>[ 40.191586][ C6] rtnl_print_btrace+0xf0/0x124
> <6>[ 40.191595][ C6] call_timer_fn+0x5c/0x3b4
> <6>[ 40.191602][ C6] expire_timers+0xe0/0x49c
> <6>[ 40.191609][ C6] __run_timers+0x34c/0x48c
> <6>[ 40.191616][ C6] run_timer_softirq+0x28/0x58
> <6>[ 40.191621][ C6] efi_header_end+0x168/0x690
> <6>[ 40.191628][ C6] __irq_exit_rcu+0x108/0x124
> <6>[ 40.191635][ C6] __handle_domain_irq+0x130/0x1b4
> <6>[ 40.191643][ C6] gic_handle_irq.29882+0x6c/0x2d8
> <6>[ 40.191648][ C6] el1_irq+0xdc/0x1c0
> <6>[ 40.191656][ C6] __delay+0xc0/0x180
> <6>[ 40.191663][ C6] devinet_ioctl+0x21c/0x75c
> <6>[ 40.191668][ C6] inet_ioctl+0xb8/0x1f8
> <6>[ 40.191675][ C6] sock_do_ioctl+0x70/0x2ac
> <6>[ 40.191682][ C6] sock_ioctl+0x5dc/0xa74
> <6>[ 40.191688][ C6] __arm64_sys_ioctl+0x178/0x1fc
> <6>[ 40.191694][ C6] el0_svc_common+0xc0/0x24c
> <6>[ 40.191699][ C6] el0_svc+0x28/0x88
> <6>[ 40.191705][ C6] el0_sync_handler+0x8c/0xf0
> <6>[ 40.191710][ C6] el0_sync+0x198/0x1c0
> <6>[ 40.191715][ C6] rtnetlink: -- rtnl_print_btrace end --
>
> <6>[ 42.181879][ T2206] rtnetlink: rtnl_lock is held by [2206] from
> [38181400013] to [42181875177]
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2021-05-09 9:42 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-08 8:57 [PATCH][v2] rtnetlink: add rtnl_lock debug log Rocco Yue
2021-05-09 9:42 ` Andy Shevchenko [this message]
[not found] ` <1620631421.29475.106.camel@mbjsdccf07>
2021-05-10 12:19 ` Andy Shevchenko
2021-05-11 18:54 ` Aw: " Frank Wunderlich
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