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[ Upstream commit56c6be35fc] As &hc->lock is acquired by both timer _hfcpci_softirq() and hardirq hfcpci_int(), the timer should disable irq before lock acquisition otherwise deadlock could happen if the timmer is preemtped by the hadr irq. Possible deadlock scenario: hfcpci_softirq() (timer) -> _hfcpci_softirq() -> spin_lock(&hc->lock); <irq interruption> -> hfcpci_int() -> spin_lock(&hc->lock); (deadlock here) This flaw was found by an experimental static analysis tool I am developing for irq-related deadlock. The tentative patch fixes the potential deadlock by spin_lock_irq() in timer. Fixes:b36b654a7e("mISDN: Create /sys/class/mISDN") Signed-off-by: Chengfeng Ye <dg573847474@gmail.com> Link: https://lore.kernel.org/r/20230727085619.7419-1-dg573847474@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
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.