Fork of alistair23 Linux kernel for reMarkable from https://github.com/alistair23/linux
5cc35c224a
There is a spinlock lockup as part of composite_disconnect when it tries to acquire cdev->lock as part of usb_gadget_deactivate. This is because the usb_gadget_deactivate is called from usb_function_deactivate with the same spinlock held. This would result in the below call stack and leads to stall. rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 3-...0: (1 GPs behind) idle=162/1/0x4000000000000000 softirq=10819/10819 fqs=2356 (detected by 2, t=5252 jiffies, g=20129, q=3770) Task dump for CPU 3: task:uvc-gadget_wlhe state:R running task stack: 0 pid: 674 ppid: 636 flags:0x00000202 Call trace: __switch_to+0xc0/0x170 _raw_spin_lock_irqsave+0x84/0xb0 composite_disconnect+0x28/0x78 configfs_composite_disconnect+0x68/0x70 usb_gadget_disconnect+0x10c/0x128 usb_gadget_deactivate+0xd4/0x108 usb_function_deactivate+0x6c/0x80 uvc_function_disconnect+0x20/0x58 uvc_v4l2_release+0x30/0x88 v4l2_release+0xbc/0xf0 __fput+0x7c/0x230 ____fput+0x14/0x20 task_work_run+0x88/0x140 do_notify_resume+0x240/0x6f0 work_pending+0x8/0x200 Fix this by doing an unlock on cdev->lock before the usb_gadget_deactivate call from usb_function_deactivate. The same lockup can happen in the usb_gadget_activate path. Fix that path as well. Reported-by: Peter Chen <peter.chen@nxp.com> Link: https://lore.kernel.org/linux-usb/20201102094936.GA29581@b29397-desktop/ Tested-by: Peter Chen <peter.chen@nxp.com> Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org> Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20201202130220.24926-1-sallenki@codeaurora.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.