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commit81b1e6e6a8upstream. Since the addition of platform MSI support, there were two helpers supposed to allocate/free IRQs for a device: platform_msi_domain_alloc_irqs() platform_msi_domain_free_irqs() In these helpers, IRQ descriptors are allocated in the "alloc" routine while they are freed in the "free" one. Later, two other helpers have been added to handle IRQ domains on top of MSI domains: platform_msi_domain_alloc() platform_msi_domain_free() Seen from the outside, the logic is pretty close with the former helpers and people used it with the same logic as before: a platform_msi_domain_alloc() call should be balanced with a platform_msi_domain_free() call. While this is probably what was intended to do, the platform_msi_domain_free() does not remove/free the IRQ descriptor(s) created/inserted in platform_msi_domain_alloc(). One effect of such situation is that removing a module that requested an IRQ will let one orphaned IRQ descriptor (with an allocated MSI entry) in the device descriptors list. Next time the module will be inserted back, one will observe that the allocation will happen twice in the MSI domain, one time for the remaining descriptor, one time for the new one. It also has the side effect to quickly overshoot the maximum number of allocated MSI and then prevent any module requesting an interrupt in the same domain to be inserted anymore. This situation has been met with loops of insertion/removal of the mvpp2.ko module (requesting 15 MSIs each time). Fixes:552c494a76("platform-msi: Allow creation of a MSI-based stacked irq domain") Cc: stable@vger.kernel.org Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.