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Message-ID: <20251002143627.GA267439@bhelgaas>
Date: Thu, 2 Oct 2025 09:36:27 -0500
From: Bjorn Helgaas <helgaas@...nel.org>
To: Siddharth Vadapalli <s-vadapalli@...com>
Cc: lpieralisi@...nel.org, kwilczynski@...nel.org, mani@...nel.org,
robh@...nel.org, bhelgaas@...gle.com, cassel@...nel.org,
kishon@...nel.org, sergio.paracuellos@...il.com,
18255117159@....com, jirislaby@...nel.org, m-karicheri2@...com,
santosh.shilimkar@...com, stable@...r.kernel.org,
linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, srk@...com
Subject: Re: [PATCH 2/2] PCI: keystone: Remove the __init macro for the
ks_pcie_host_init() callback
On Fri, Sep 12, 2025 at 03:37:59PM +0530, Siddharth Vadapalli wrote:
> The ks_pcie_host_init() callback registered by the driver is invoked by
> dw_pcie_host_init(). Since the driver probe is not guaranteed to finish
> before the kernel initialization phase, the memory associated with
> ks_pcie_host_init() may already be freed by free_initmem().
>
> It is observed in practice that the print associated with free_initmem()
> which is:
> "Freeing unused kernel memory: ..."
> is displayed before the driver is probed, following which an exception is
> triggered when ks_pcie_host_init() is invoked which looks like:
>
> Unable to handle kernel paging request at virtual address ...
> Mem abort info:
> ...
> pc : ks_pcie_host_init+0x0/0x540
> lr : dw_pcie_host_init+0x170/0x498
> ...
> ks_pcie_host_init+0x0/0x540 (P)
> ks_pcie_probe+0x728/0x84c
> platform_probe+0x5c/0x98
> really_probe+0xbc/0x29c
> __driver_probe_device+0x78/0x12c
> driver_probe_device+0xd8/0x15c
> ...
>
> Fix this by removing the "__init" macro associated with the
> ks_pcie_host_init() callback and the ks_pcie_init_id() function that it
> internally invokes.
>
> Fixes: 0c4ffcfe1fbc ("PCI: keystone: Add TI Keystone PCIe driver")
> Cc: <stable@...r.kernel.org>
> Signed-off-by: Siddharth Vadapalli <s-vadapalli@...com>
I dropped this from pci/controller/keystone because of the resulting
section mismatch:
https://lore.kernel.org/r/202510010726.GPljD7FR-lkp@intel.com
ks_pcie_host_init() calls hook_fault_code(), which is __init, so we
can't make ks_pcie_host_init() non-__init.
Both are bad problems, but there's no point in just swapping one
problem for a different one.
> ---
> drivers/pci/controller/dwc/pci-keystone.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c
> index 21808a9e5158..c6e082dcb3bc 100644
> --- a/drivers/pci/controller/dwc/pci-keystone.c
> +++ b/drivers/pci/controller/dwc/pci-keystone.c
> @@ -799,7 +799,7 @@ static int ks_pcie_fault(unsigned long addr, unsigned int fsr,
> }
> #endif
>
> -static int __init ks_pcie_init_id(struct keystone_pcie *ks_pcie)
> +static int ks_pcie_init_id(struct keystone_pcie *ks_pcie)
> {
> int ret;
> unsigned int id;
> @@ -831,7 +831,7 @@ static int __init ks_pcie_init_id(struct keystone_pcie *ks_pcie)
> return 0;
> }
>
> -static int __init ks_pcie_host_init(struct dw_pcie_rp *pp)
> +static int ks_pcie_host_init(struct dw_pcie_rp *pp)
> {
> struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> struct keystone_pcie *ks_pcie = to_keystone_pcie(pci);
> --
> 2.43.0
>
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