linux-kernel - Re: [PATCH v2] PCI: cadence: Fix runtime atomic count underflow.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <pjacxodfaywqxabqeftguqcrz2eoib5l5l32oevy5j5rrwl5s6@hhglbkyrmnzg>
Date: Sat, 19 Apr 2025 22:21:53 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To: Hans Zhang <18255117159@....com>
Cc: lpieralisi@...nel.org, kw@...ux.com, robh@...nel.org, 
	bhelgaas@...gle.com, s-vadapalli@...com, thomas.richard@...tlin.com, 
	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org, rockswang7@...il.com
Subject: Re: [PATCH v2] PCI: cadence: Fix runtime atomic count underflow.

On Sat, Apr 19, 2025 at 09:30:58PM +0800, Hans Zhang wrote:
> If the call to pci_host_probe() in cdns_pcie_host_setup()
> fails, PM runtime count is decremented in the error path using
> pm_runtime_put_sync().But the runtime count is not incremented by this
> driver, but only by the callers (cdns_plat_pcie_probe/j721e_pcie_probe).
> And the callers also decrement theruntime PM count in their error path.
> So this leads to the below warning from the PM core:
> 
> runtime PM usage count underflow!
> 
> So fix it by getting rid of pm_runtime_put_sync() in the error path and
> directly return the errno.
> 
> Fixes: 1b79c5284439 ("PCI: cadence: Add host driver for Cadence PCIe controller")
> 

This is not the correct Fixes commit. In fact it took me a while to find the
correct one. This exact same issue was already fixed by commit, 19abcd790b51
("PCI: cadence: Fix cdns_pcie_{host|ep}_setup() error path").

But then, this bug got reintroduced while fixing the merge conflict in:
49e427e6bdd1 ("Merge branch 'pci/host-probe-refactor'")

I will change the tag while applying.

- Mani

> Signed-off-by: Hans Zhang <18255117159@....com>
> ---
>  drivers/pci/controller/cadence/pcie-cadence-host.c | 11 +----------
>  1 file changed, 1 insertion(+), 10 deletions(-)
> 
> diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c b/drivers/pci/controller/cadence/pcie-cadence-host.c
> index 8af95e9da7ce..741e10a575ec 100644
> --- a/drivers/pci/controller/cadence/pcie-cadence-host.c
> +++ b/drivers/pci/controller/cadence/pcie-cadence-host.c
> @@ -570,14 +570,5 @@ int cdns_pcie_host_setup(struct cdns_pcie_rc *rc)
>  	if (!bridge->ops)
>  		bridge->ops = &cdns_pcie_host_ops;
>  
> -	ret = pci_host_probe(bridge);
> -	if (ret < 0)
> -		goto err_init;
> -
> -	return 0;
> -
> - err_init:
> -	pm_runtime_put_sync(dev);
> -
> -	return ret;
> +	return pci_host_probe(bridge);
>  }
> 
> base-commit: a24588245776dafc227243a01bfbeb8a59bafba9
> -- 
> 2.25.1
> 

-- 
மணிவண்ணன் சதாசிவம்