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From: Christian Brauner <brauner@kernel.org>
To: Ming Lei <ming.lei@redhat.com>
Cc: linux-fsdevel@vger.kernel.org,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
	Changhui Zhong <czhong@redhat.com>
Subject: Re: [czhong@redhat.com: [bug report] WARNING: CPU: 121 PID: 93233 at fs/dcache.c:365 __dentry_kill+0x214/0x278]
Date: Wed, 23 Aug 2023 10:47:27 +0200	[thread overview]
Message-ID: <20230823-kuppe-lassen-bc81a20dd831@brauner> (raw)
In-Reply-To: <ZOWFtqA2om0w5Vmz@fedora>

On Wed, Aug 23, 2023 at 12:06:14PM +0800, Ming Lei wrote:
> 
> Looks the issue is more related with vfs, so forward to vfs list.
> 
> ----- Forwarded message from Changhui Zhong <czhong@redhat.com> -----
> 
> Date: Wed, 23 Aug 2023 11:17:55 +0800
> From: Changhui Zhong <czhong@redhat.com>
> To: linux-scsi@vger.kernel.org
> Cc: Ming Lei <ming.lei@redhat.com>
> Subject: [bug report] WARNING: CPU: 121 PID: 93233 at fs/dcache.c:365 __dentry_kill+0x214/0x278
> 
> Hello,
> 
> triggered below warning issue with branch
> "
> Tree: mainline.kernel.org-clang
> Repository: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> @ master
> Commit Hash: 89bf6209cad66214d3774dac86b6bbf2aec6a30d
> Commit Name: v6.5-rc7-18-g89bf6209cad6
> Kernel information:
> Commit message: Merge tag 'devicetree-fixes-for-6.5-2' of
> git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux
> "
> for more detail,please check
> https://datawarehouse.cki-project.org/kcidb/tests/9232643
> 
> #modprobe scsi_debug virtual_gb=128
> #echo none > /sys/block/sdb/queue/scheduler
> #fio --bs=4k --ioengine=libaio --iodepth=1 --numjobs=4 --rw=randrw
> --name=sdb-libaio-randrw-4k --filename=/dev/sdb --direct=1 --size=60G
> --runtime=60

Looking at this issue it seems unlikely that this is a vfs bug.
We should see this all over the place and specifically not just on arm64.

The sequence here seems to be:

echo 4 > /proc/sys/vm/drop_caches
rmmod scsi_debug > /dev/null 3>&1

[ 3117.059778] WARNING: CPU: 121 PID: 93233 at fs/dcache.c:365 __dentry_kill+0x214/0x278 
[ 3117.067601] Modules linked in: scsi_debug nvme nvme_core nvme_common null_blk pktcdvd ipmi_watchdog ipmi_poweroff rfkill sunrpc vfat fat acpi_ipmi ipmi_ssif arm_spe_pmu igb ipmi_devintf ipmi_msghandler arm_cmn arm_dmc620_pmu cppc_cpufreq arm_dsu_pmu acpi_tad loop fuse zram xfs crct10dif_ce polyval_ce polyval_generic ghash_ce sbsa_gwdt ast onboard_usb_hub i2c_algo_bit xgene_hwmon [last unloaded: scsi_debug]

So my money is on some device that gets removed still having an
increased refcount and pinning the dentry. Immediate suspects would be:

7882541ca06d ("of/platform: increase refcount of fwnode")

but that part is complete speculation on my part.

  reply	other threads:[~2023-08-23  8:50 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-23  4:06 [czhong@redhat.com: [bug report] WARNING: CPU: 121 PID: 93233 at fs/dcache.c:365 __dentry_kill+0x214/0x278] Ming Lei
2023-08-23  8:47 ` Christian Brauner [this message]
2023-08-28 10:43   ` Ming Lei
2023-09-13  8:59     ` Yi Zhang
2023-09-16  6:55       ` Baokun Li
2023-09-17  9:10         ` Peter Zijlstra
2023-09-17  9:26           ` Peter Zijlstra
2023-09-18  1:52             ` Baokun Li
2023-09-18 18:42               ` Darrick J. Wong
2023-09-18  1:10           ` Baokun Li
2023-09-18 10:20             ` Yi Zhang
2023-09-19 15:10         ` Mark Rutland
2023-09-17  0:35       ` Bagas Sanjaya
2023-09-29 13:24         ` Linux regression tracking #update (Thorsten Leemhuis)

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