linux-kernel - Re: [PATCH v2 1/2] PCI: plda: Remove unused IRQ handler and simplify IRQ request logic

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Message-ID: <dmzf2lup7iiqcqhq773rtrikb7sleoq743q7nbakrcpvcbzuf4@54qbngfpw2bc>
Date: Sat, 19 Apr 2025 15:55:23 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To: Anand Moon <linux.amoon@...il.com>
Cc: Daire McNamara <daire.mcnamara@...rochip.com>, 
	Lorenzo Pieralisi <lpieralisi@...nel.org>, Krzysztof Wilczyński <kw@...ux.com>, 
	Rob Herring <robh@...nel.org>, Bjorn Helgaas <bhelgaas@...gle.com>, 
	Kevin Xie <kevin.xie@...rfivetech.com>, Minda Chen <minda.chen@...rfivetech.com>, 
	Conor Dooley <conor.dooley@...rochip.com>, Mason Huo <mason.huo@...rfivetech.com>, 
	"open list:PCI DRIVER FOR PLDA PCIE IP" <linux-pci@...r.kernel.org>, open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 1/2] PCI: plda: Remove unused IRQ handler and simplify
 IRQ request logic

On Sun, Mar 16, 2025 at 10:42:45PM +0530, Anand Moon wrote:
> The plda_event_handler() function has been removed since it only returned
> IRQ_HANDLED without performing any processing. Additionally, the IRQ
> request logic in plda_init_interrupts() has been streamlined by removing
> the redundant devm_request_irq() call when the request_event_irq()
> callback is not defined.
> 
> Change ensures that interrupts are requested exclusively through the
> request_event_irq() callback when available, enhancing code clarity
> and maintainability.
> 

Could you please reword the description in the imperative form? I have
mentioned this a couple of times in the past, but you are still not following it
:(

> Changes help fix kmemleak reported following debug log.
> 

But you didn't say 'how'. In your last version you mentioned that it could be
due to passing NULL as the 'devname' to devm_request_irq(). Can you verify that
by passing an arbitrary name and see if the leak is disappearing?

> $ sudo cat /sys/kernel/debug/kmemleak
> unreferenced object 0xffffffd6c47c2600 (size 128):
>   comm "kworker/u16:2", pid 38, jiffies 4294942263
>   hex dump (first 32 bytes):
>     cc 7c 5a 8d ff ff ff ff 40 b0 47 c8 d6 ff ff ff  .|Z.....@.......
>     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>   backtrace (crc 4f07ff07):
>     __create_object+0x2a/0xfc
>     kmemleak_alloc+0x38/0x98
>     __kmalloc_cache_noprof+0x296/0x444
>     request_threaded_irq+0x168/0x284
>     devm_request_threaded_irq+0xa8/0x13c
>     plda_init_interrupts+0x46e/0x858
>     plda_pcie_host_init+0x356/0x468
>     starfive_pcie_probe+0x2f6/0x398
>     platform_probe+0x106/0x150
>     really_probe+0x30e/0x746
>     __driver_probe_device+0x11c/0x2c2
>     driver_probe_device+0x5e/0x316
>     __device_attach_driver+0x296/0x3a4
>     bus_for_each_drv+0x1d0/0x260
>     __device_attach+0x1fa/0x2d6
>     device_initial_probe+0x14/0x28
> unreferenced object 0xffffffd6c47c2900 (size 128):
>   comm "kworker/u16:2", pid 38, jiffies 4294942281
> 
> Fixes: 4602c370bdf6 ("PCI: microchip: Move IRQ functions to pcie-plda-host.c")

This tag is not the one introduced the bug. It just moves the core around.

- Mani

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