From: Jia-Ju Bai <baijiaju1990@gmail.com>
To: hao.wu@intel.com, trix@redhat.com, mdf@kernel.org
Cc: linux-fpga@vger.kernel.org, linux-kernel <linux-kernel@vger.kernel.org>
Subject: [BUG] fpga: dfl: possible ABBA deadlock in dfl_fpga_cdev_assign_port() and fme_pr()
Date: Tue, 23 Nov 2021 15:55:16 +0800 [thread overview]
Message-ID: <9460c1ba-addd-9757-fe55-ceeeae596ac1@gmail.com> (raw)
Hello,
My static analysis tool reports a possible ABBA deadlock in the dfl
driver in Linux 5.10:
dfl_fpga_cdev_assign_port()
mutex_lock(&cdev->lock); --> Line 1067 (Lock A)
mutex_lock(&pdata->lock); --> Line 1624 (Lock B)
fme_pr()
mutex_lock(&pdata->lock); --> Line 126 (Lock B)
fpga_region_program_fpga()
fpga_bridges_enable()
fpga_bridge_enable()
fme_bridge_enable_set() --> function pointer via
"bridge->br_ops->enable_set()"
dfl_fpga_cdev_find_port()
mutex_lock(&cdev->lock); --> Line 499 (LockA)
When dfl_fpga_cdev_assign_port() and fme_pr() are concurrently executed,
the deadlock can occur.
I am not quite sure whether this possible deadlock is real and how to
fix it if it is real.
Any feedback would be appreciated, thanks
Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Best wishes,
Jia-Ju Bai
next reply other threads:[~2021-11-23 7:55 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-23 7:55 Jia-Ju Bai [this message]
2021-11-24 15:59 ` [BUG] fpga: dfl: possible ABBA deadlock in dfl_fpga_cdev_assign_port() and fme_pr() Wu, Hao
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