* [PATCH 1/1] PCI: Do not size non-existing prefetchable window
@ 2025-10-27 13:24 Ilpo Järvinen
2025-10-27 17:45 ` Klaus Kudielka
2025-10-27 23:12 ` Bjorn Helgaas
0 siblings, 2 replies; 5+ messages in thread
From: Ilpo Järvinen @ 2025-10-27 13:24 UTC (permalink / raw)
To: Klaus Kudielka, Bjorn Helgaas, Ilpo Järvinen, linux-pci,
linux-kernel
pbus_size_mem() should only be called for bridge windows that exist but
__pci_bus_size_bridges() may point 'pref' to a resource that does not
exist (has zero flags) in case of non-root buses.
When prefetchable bridge window does not exist, the same
non-prefetchable bridge window is sized more than once which may result
in duplicating entries into the realloc_head list. Duplicated entries
are shown in this log and trigger a WARN_ON() because realloc_head had
residual entries after the resource assignment algorithm:
pci 0000:00:03.0: [11ab:6820] type 01 class 0x060400 PCIe Root Port
pci 0000:00:03.0: PCI bridge to [bus 00]
pci 0000:00:03.0: bridge window [io 0x0000-0x0fff]
pci 0000:00:03.0: bridge window [mem 0x00000000-0x000fffff]
pci 0000:00:03.0: bridge window [mem 0x00200000-0x003fffff] to [bus 02] add_size 200000 add_align 200000
pci 0000:00:03.0: bridge window [mem 0x00200000-0x003fffff] to [bus 02] add_size 200000 add_align 200000
pci 0000:00:03.0: bridge window [mem 0xe0000000-0xe03fffff]: assigned
pci 0000:00:03.0: PCI bridge to [bus 02]
pci 0000:00:03.0: bridge window [mem 0xe0000000-0xe03fffff]
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at drivers/pci/setup-bus.c:2373 pci_assign_unassigned_root_bus_resources+0x1bc/0x234
Check resource flags of 'pref' and only size the prefetchable window if
the resource has the IORESOURCE_PREFETCH flag.
Fixes: ae88d0b9c57f ("PCI: Use pbus_select_window_for_type() during mem window sizing")
Link: https://lore.kernel.org/linux-pci/51e8cf1c62b8318882257d6b5a9de7fdaaecc343.camel@gmail.com/
Reported-by: Klaus Kudielka <klaus.kudielka@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
drivers/pci/setup-bus.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 362ad108794d..7cb6071cff7a 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1604,7 +1604,7 @@ void __pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head)
pbus_size_io(bus, realloc_head ? 0 : additional_io_size,
additional_io_size, realloc_head);
- if (pref) {
+ if (pref && (pref->flags & IORESOURCE_PREFETCH)) {
pbus_size_mem(bus,
IORESOURCE_MEM | IORESOURCE_PREFETCH |
(pref->flags & IORESOURCE_MEM_64),
base-commit: 2f2c7254931f41b5736e3ba12aaa9ac1bbeeeb92
--
2.39.5
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH 1/1] PCI: Do not size non-existing prefetchable window
2025-10-27 13:24 [PATCH 1/1] PCI: Do not size non-existing prefetchable window Ilpo Järvinen
@ 2025-10-27 17:45 ` Klaus Kudielka
2025-10-27 17:55 ` Ilpo Järvinen
2025-10-27 23:12 ` Bjorn Helgaas
1 sibling, 1 reply; 5+ messages in thread
From: Klaus Kudielka @ 2025-10-27 17:45 UTC (permalink / raw)
To: Ilpo Järvinen, Bjorn Helgaas, linux-pci, linux-kernel
On Mon, 2025-10-27 at 15:24 +0200, Ilpo Järvinen wrote:
> pbus_size_mem() should only be called for bridge windows that exist but
> __pci_bus_size_bridges() may point 'pref' to a resource that does not
> exist (has zero flags) in case of non-root buses.
>
> When prefetchable bridge window does not exist, the same
> non-prefetchable bridge window is sized more than once which may result
> in duplicating entries into the realloc_head list. Duplicated entries
> are shown in this log and trigger a WARN_ON() because realloc_head had
> residual entries after the resource assignment algorithm:
>
> pci 0000:00:03.0: [11ab:6820] type 01 class 0x060400 PCIe Root Port
> pci 0000:00:03.0: PCI bridge to [bus 00]
> pci 0000:00:03.0: bridge window [io 0x0000-0x0fff]
> pci 0000:00:03.0: bridge window [mem 0x00000000-0x000fffff]
> pci 0000:00:03.0: bridge window [mem 0x00200000-0x003fffff] to [bus 02] add_size 200000 add_align 200000
> pci 0000:00:03.0: bridge window [mem 0x00200000-0x003fffff] to [bus 02] add_size 200000 add_align 200000
> pci 0000:00:03.0: bridge window [mem 0xe0000000-0xe03fffff]: assigned
> pci 0000:00:03.0: PCI bridge to [bus 02]
> pci 0000:00:03.0: bridge window [mem 0xe0000000-0xe03fffff]
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 1 at drivers/pci/setup-bus.c:2373 pci_assign_unassigned_root_bus_resources+0x1bc/0x234
With this patch on top of v6.18-rc3, the boot log looks clean again:
pci 0000:00:03.0: [11ab:6820] type 01 class 0x060400 PCIe Root Port
pci 0000:00:03.0: PCI bridge to [bus 00]
pci 0000:00:03.0: bridge window [io 0x0000-0x0fff]
pci 0000:00:03.0: bridge window [mem 0x00000000-0x000fffff]
pci 0000:00:03.0: bridge configuration invalid ([bus 00-00]), reconfiguring
pci 0000:00:03.0: bridge window [mem 0x00200000-0x003fffff] to [bus 02] add_size 200000 add_align 200000
pci 0000:00:03.0: bridge window [mem 0xe0000000-0xe03fffff]: assigned
pci 0000:00:03.0: PCI bridge to [bus 02]
pci 0000:00:03.0: bridge window [mem 0xe0000000-0xe03fffff]
(and no WARNING thereafter)
Thanks a lot!
Tested-by: Klaus Kudielka <klaus.kudielka@gmail.com>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 1/1] PCI: Do not size non-existing prefetchable window
2025-10-27 17:45 ` Klaus Kudielka
@ 2025-10-27 17:55 ` Ilpo Järvinen
0 siblings, 0 replies; 5+ messages in thread
From: Ilpo Järvinen @ 2025-10-27 17:55 UTC (permalink / raw)
To: Klaus Kudielka; +Cc: Bjorn Helgaas, linux-pci, LKML
[-- Attachment #1: Type: text/plain, Size: 2326 bytes --]
On Mon, 27 Oct 2025, Klaus Kudielka wrote:
> On Mon, 2025-10-27 at 15:24 +0200, Ilpo Järvinen wrote:
> > pbus_size_mem() should only be called for bridge windows that exist but
> > __pci_bus_size_bridges() may point 'pref' to a resource that does not
> > exist (has zero flags) in case of non-root buses.
> >
> > When prefetchable bridge window does not exist, the same
> > non-prefetchable bridge window is sized more than once which may result
> > in duplicating entries into the realloc_head list. Duplicated entries
> > are shown in this log and trigger a WARN_ON() because realloc_head had
> > residual entries after the resource assignment algorithm:
> >
> > pci 0000:00:03.0: [11ab:6820] type 01 class 0x060400 PCIe Root Port
> > pci 0000:00:03.0: PCI bridge to [bus 00]
> > pci 0000:00:03.0: bridge window [io 0x0000-0x0fff]
> > pci 0000:00:03.0: bridge window [mem 0x00000000-0x000fffff]
> > pci 0000:00:03.0: bridge window [mem 0x00200000-0x003fffff] to [bus 02] add_size 200000 add_align 200000
> > pci 0000:00:03.0: bridge window [mem 0x00200000-0x003fffff] to [bus 02] add_size 200000 add_align 200000
> > pci 0000:00:03.0: bridge window [mem 0xe0000000-0xe03fffff]: assigned
> > pci 0000:00:03.0: PCI bridge to [bus 02]
> > pci 0000:00:03.0: bridge window [mem 0xe0000000-0xe03fffff]
> > ------------[ cut here ]------------
> > WARNING: CPU: 0 PID: 1 at drivers/pci/setup-bus.c:2373 pci_assign_unassigned_root_bus_resources+0x1bc/0x234
>
> With this patch on top of v6.18-rc3, the boot log looks clean again:
>
> pci 0000:00:03.0: [11ab:6820] type 01 class 0x060400 PCIe Root Port
> pci 0000:00:03.0: PCI bridge to [bus 00]
> pci 0000:00:03.0: bridge window [io 0x0000-0x0fff]
> pci 0000:00:03.0: bridge window [mem 0x00000000-0x000fffff]
> pci 0000:00:03.0: bridge configuration invalid ([bus 00-00]), reconfiguring
> pci 0000:00:03.0: bridge window [mem 0x00200000-0x003fffff] to [bus 02] add_size 200000 add_align 200000
> pci 0000:00:03.0: bridge window [mem 0xe0000000-0xe03fffff]: assigned
> pci 0000:00:03.0: PCI bridge to [bus 02]
> pci 0000:00:03.0: bridge window [mem 0xe0000000-0xe03fffff]
>
> (and no WARNING thereafter)
> Thanks a lot!
>
> Tested-by: Klaus Kudielka <klaus.kudielka@gmail.com>
Thanks for testing.
--
i.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 1/1] PCI: Do not size non-existing prefetchable window
2025-10-27 13:24 [PATCH 1/1] PCI: Do not size non-existing prefetchable window Ilpo Järvinen
2025-10-27 17:45 ` Klaus Kudielka
@ 2025-10-27 23:12 ` Bjorn Helgaas
2025-10-27 23:15 ` Ilpo Järvinen
1 sibling, 1 reply; 5+ messages in thread
From: Bjorn Helgaas @ 2025-10-27 23:12 UTC (permalink / raw)
To: Ilpo Järvinen; +Cc: Klaus Kudielka, Bjorn Helgaas, linux-pci, linux-kernel
On Mon, Oct 27, 2025 at 03:24:23PM +0200, Ilpo Järvinen wrote:
> pbus_size_mem() should only be called for bridge windows that exist but
> __pci_bus_size_bridges() may point 'pref' to a resource that does not
> exist (has zero flags) in case of non-root buses.
>
> When prefetchable bridge window does not exist, the same
> non-prefetchable bridge window is sized more than once which may result
> in duplicating entries into the realloc_head list. Duplicated entries
> are shown in this log and trigger a WARN_ON() because realloc_head had
> residual entries after the resource assignment algorithm:
>
> pci 0000:00:03.0: [11ab:6820] type 01 class 0x060400 PCIe Root Port
> pci 0000:00:03.0: PCI bridge to [bus 00]
> pci 0000:00:03.0: bridge window [io 0x0000-0x0fff]
> pci 0000:00:03.0: bridge window [mem 0x00000000-0x000fffff]
> pci 0000:00:03.0: bridge window [mem 0x00200000-0x003fffff] to [bus 02] add_size 200000 add_align 200000
> pci 0000:00:03.0: bridge window [mem 0x00200000-0x003fffff] to [bus 02] add_size 200000 add_align 200000
> pci 0000:00:03.0: bridge window [mem 0xe0000000-0xe03fffff]: assigned
> pci 0000:00:03.0: PCI bridge to [bus 02]
> pci 0000:00:03.0: bridge window [mem 0xe0000000-0xe03fffff]
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 1 at drivers/pci/setup-bus.c:2373 pci_assign_unassigned_root_bus_resources+0x1bc/0x234
>
> Check resource flags of 'pref' and only size the prefetchable window if
> the resource has the IORESOURCE_PREFETCH flag.
>
> Fixes: ae88d0b9c57f ("PCI: Use pbus_select_window_for_type() during mem window sizing")
> Link: https://lore.kernel.org/linux-pci/51e8cf1c62b8318882257d6b5a9de7fdaaecc343.camel@gmail.com/
> Reported-by: Klaus Kudielka <klaus.kudielka@gmail.com>
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Since ae88d0b9c57f appeared in v6.18-rc1, this looks like v6.18
material, right?
Applied to pci/for-linus for v6.18 on that assumption, thanks!
> ---
> drivers/pci/setup-bus.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index 362ad108794d..7cb6071cff7a 100644
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c
> @@ -1604,7 +1604,7 @@ void __pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head)
> pbus_size_io(bus, realloc_head ? 0 : additional_io_size,
> additional_io_size, realloc_head);
>
> - if (pref) {
> + if (pref && (pref->flags & IORESOURCE_PREFETCH)) {
> pbus_size_mem(bus,
> IORESOURCE_MEM | IORESOURCE_PREFETCH |
> (pref->flags & IORESOURCE_MEM_64),
>
> base-commit: 2f2c7254931f41b5736e3ba12aaa9ac1bbeeeb92
> --
> 2.39.5
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 1/1] PCI: Do not size non-existing prefetchable window
2025-10-27 23:12 ` Bjorn Helgaas
@ 2025-10-27 23:15 ` Ilpo Järvinen
0 siblings, 0 replies; 5+ messages in thread
From: Ilpo Järvinen @ 2025-10-27 23:15 UTC (permalink / raw)
To: Bjorn Helgaas; +Cc: Klaus Kudielka, Bjorn Helgaas, linux-pci, LKML
[-- Attachment #1: Type: text/plain, Size: 2977 bytes --]
On Mon, 27 Oct 2025, Bjorn Helgaas wrote:
> On Mon, Oct 27, 2025 at 03:24:23PM +0200, Ilpo Järvinen wrote:
> > pbus_size_mem() should only be called for bridge windows that exist but
> > __pci_bus_size_bridges() may point 'pref' to a resource that does not
> > exist (has zero flags) in case of non-root buses.
> >
> > When prefetchable bridge window does not exist, the same
> > non-prefetchable bridge window is sized more than once which may result
> > in duplicating entries into the realloc_head list. Duplicated entries
> > are shown in this log and trigger a WARN_ON() because realloc_head had
> > residual entries after the resource assignment algorithm:
> >
> > pci 0000:00:03.0: [11ab:6820] type 01 class 0x060400 PCIe Root Port
> > pci 0000:00:03.0: PCI bridge to [bus 00]
> > pci 0000:00:03.0: bridge window [io 0x0000-0x0fff]
> > pci 0000:00:03.0: bridge window [mem 0x00000000-0x000fffff]
> > pci 0000:00:03.0: bridge window [mem 0x00200000-0x003fffff] to [bus 02] add_size 200000 add_align 200000
> > pci 0000:00:03.0: bridge window [mem 0x00200000-0x003fffff] to [bus 02] add_size 200000 add_align 200000
> > pci 0000:00:03.0: bridge window [mem 0xe0000000-0xe03fffff]: assigned
> > pci 0000:00:03.0: PCI bridge to [bus 02]
> > pci 0000:00:03.0: bridge window [mem 0xe0000000-0xe03fffff]
> > ------------[ cut here ]------------
> > WARNING: CPU: 0 PID: 1 at drivers/pci/setup-bus.c:2373 pci_assign_unassigned_root_bus_resources+0x1bc/0x234
> >
> > Check resource flags of 'pref' and only size the prefetchable window if
> > the resource has the IORESOURCE_PREFETCH flag.
> >
> > Fixes: ae88d0b9c57f ("PCI: Use pbus_select_window_for_type() during mem window sizing")
> > Link: https://lore.kernel.org/linux-pci/51e8cf1c62b8318882257d6b5a9de7fdaaecc343.camel@gmail.com/
> > Reported-by: Klaus Kudielka <klaus.kudielka@gmail.com>
> > Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
>
> Since ae88d0b9c57f appeared in v6.18-rc1, this looks like v6.18
> material, right?
>
> Applied to pci/for-linus for v6.18 on that assumption, thanks!
Yes, it's for-linus material.
--
i.
> > drivers/pci/setup-bus.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> > index 362ad108794d..7cb6071cff7a 100644
> > --- a/drivers/pci/setup-bus.c
> > +++ b/drivers/pci/setup-bus.c
> > @@ -1604,7 +1604,7 @@ void __pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head)
> > pbus_size_io(bus, realloc_head ? 0 : additional_io_size,
> > additional_io_size, realloc_head);
> >
> > - if (pref) {
> > + if (pref && (pref->flags & IORESOURCE_PREFETCH)) {
> > pbus_size_mem(bus,
> > IORESOURCE_MEM | IORESOURCE_PREFETCH |
> > (pref->flags & IORESOURCE_MEM_64),
> >
> > base-commit: 2f2c7254931f41b5736e3ba12aaa9ac1bbeeeb92
> > --
> > 2.39.5
> >
>
^ permalink raw reply [flat|nested] 5+ messages in thread
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Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2025-10-27 13:24 [PATCH 1/1] PCI: Do not size non-existing prefetchable window Ilpo Järvinen
2025-10-27 17:45 ` Klaus Kudielka
2025-10-27 17:55 ` Ilpo Järvinen
2025-10-27 23:12 ` Bjorn Helgaas
2025-10-27 23:15 ` Ilpo Järvinen
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