linux-kernel - RE: [PATCH v7 3/5] Add debugfs based silicon debug support in DWC

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: <075401db8f44$88861bc0$99925340$@samsung.com>
Date: Fri, 7 Mar 2025 15:07:20 +0530
From: "Shradha Todi" <shradha.t@...sung.com>
To: 'Krzysztof Wilczyński' <kw@...ux.com>, "'Geert
 Uytterhoeven'" <geert@...ux-m68k.org>
Cc: "'Manivannan Sadhasivam'" <manivannan.sadhasivam@...aro.org>, "'Bjorn
 Helgaas'" <helgaas@...nel.org>, "'Fan Ni'" <nifan.cxl@...il.com>,
	<linux-kernel@...r.kernel.org>, <linux-pci@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>, <linux-perf-users@...r.kernel.org>,
	<lpieralisi@...nel.org>, <robh@...nel.org>, <bhelgaas@...gle.com>,
	<jingoohan1@...il.com>, <Jonathan.Cameron@...wei.com>,
	<a.manzanares@...sung.com>, <pankaj.dubey@...sung.com>, <cassel@...nel.org>,
	<18255117159@....com>, <xueshuai@...ux.alibaba.com>,
	<renyu.zj@...ux.alibaba.com>, <will@...nel.org>, <mark.rutland@....com>,
	"'Yoshihiro Shimoda'" <yoshihiro.shimoda.uh@...esas.com>, "'Linux-Renesas'"
	<linux-renesas-soc@...r.kernel.org>
Subject: RE: [PATCH v7 3/5] Add debugfs based silicon debug support in DWC



> -----Original Message-----
> From: Krzysztof Wilczyński <kw@...ux.com>
> Sent: 06 March 2025 14:33
> To: Geert Uytterhoeven <geert@...ux-m68k.org>
> Cc: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>; Bjorn Helgaas <helgaas@...nel.org>; Fan Ni
> <nifan.cxl@...il.com>; Shradha Todi <shradha.t@...sung.com>; linux-kernel@...r.kernel.org; linux-pci@...r.kernel.org; linux-
> arm-kernel@...ts.infradead.org; linux-perf-users@...r.kernel.org; lpieralisi@...nel.org; robh@...nel.org; bhelgaas@...gle.com;
> jingoohan1@...il.com; Jonathan.Cameron@...wei.com; a.manzanares@...sung.com; pankaj.dubey@...sung.com;
> cassel@...nel.org; 18255117159@....com; xueshuai@...ux.alibaba.com; renyu.zj@...ux.alibaba.com; will@...nel.org;
> mark.rutland@....com; Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>; Linux-Renesas <linux-renesas-
> soc@...r.kernel.org>
> Subject: Re: [PATCH v7 3/5] Add debugfs based silicon debug support in DWC
> 
> Hello,
> 
> [...]
> > Another issue is that the caller does not handle failures correctly,
> > given (A) the irqdomain WARNING I got, and (B) the half-registered PCI
> > bus, oopsing on "lspci"...
> 
> This is something we will look into.  A more robust DesignWare core is something we would definitely want to have.
> 

The issue here was that " pci_host_probe(bridge)" was being called right before doing the debugfs init.
So upon failure, the cleanup path should have included:
        pci_stop_root_bus(pp->bridge->bus);
        pci_remove_root_bus(pp->bridge->bus);

I missed that, which was probably causing the half-registered PCI bus. Since we are going with no error
propagation now, there is no issue anymore. Sorry for missing that.

> Sorry about the issues with this...
> 
> [...]
> > > -int dwc_pcie_debugfs_init(struct dw_pcie *pci)
> > > +void dwc_pcie_debugfs_init(struct dw_pcie *pci)
> > >  {
> > >         char dirname[DWC_DEBUGFS_BUF_MAX];
> > >         struct device *dev = pci->dev; @@ -174,17 +174,15 @@ int
> > > dwc_pcie_debugfs_init(struct dw_pcie *pci)
> > >         snprintf(dirname, DWC_DEBUGFS_BUF_MAX, "dwc_pcie_%s", dev_name(dev));
> > >         dir = debugfs_create_dir(dirname, NULL);
> > >         debugfs = devm_kzalloc(dev, sizeof(*debugfs), GFP_KERNEL);
> > > -       if (!debugfs)
> > > -               return -ENOMEM;
> > > +       if (!debugfs) {
> > > +               dev_err(dev, "failed to allocate memory for
> > > + debugfs\n");
> >
> > There is no need to print an error message when a memory allocation
> > fails, as the memory allocation core already takes care of that.
> > So please drop the dev_err() call.
> 
> Done.  Thank you!
> 
> 	Krzysztof