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Commit 18126f35 authored by Linas Vepstas's avatar Linas Vepstas Committed by Paul Mackerras
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[PATCH] ppc64: bugfix: crash on PCI hotplug 



09-hotplug-bugfix.patch

In the current 2.6.14-rc2-git6 kernel, performing a Dynamic LPAR Add
of a hotplug slot will crash the system, with the following (abbreviated)
stack trace:

cpu 0x3: Vector: 700 (Program Check) at [c000000053dff7f0]
    pc: c0000000004f5974: .__alloc_bootmem+0x0/0xb0
    lr: c0000000000258a0: .update_dn_pci_info+0x108/0x118
        c0000000000257c8 .update_dn_pci_info+0x30/0x118 (unreliable)
        c0000000000258fc .pci_dn_reconfig_notifier+0x4c/0x64
        c000000000060754 .notifier_call_chain+0x68/0x9c

The root cause was that __init __alloc_bootmem() was called long after
boot had finished, resulting in a crash because this routine is undefined
after boot time.  The patch below fixes this crash, and adds some docs to
clarify the code.

Signed-off-by: default avatarLinas Vepstas <linas@austin.ibm.com>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent 5c1344e9

arch/ppc64/kernel/pci_dn.c

+17 −4
Original line number Diff line number Diff line
@@ -43,7 +43,7 @@ static void * __devinit update_dn_pci_info(struct device_node *dn, void *data) 
	u32 *regs;

	struct pci_dn *pdn;



	if (phb->is_dynamic)

	if (mem_init_done)

		pdn = kmalloc(sizeof(*pdn), GFP_KERNEL);

	else

		pdn = alloc_bootmem(sizeof(*pdn));
@@ -120,6 +120,14 @@ void *traverse_pci_devices(struct device_node *start, traverse_func pre, 
	return NULL;

}



/** 

 * pci_devs_phb_init_dynamic - setup pci devices under this PHB

 * phb: pci-to-host bridge (top-level bridge connecting to cpu)

 *

 * This routine is called both during boot, (before the memory

 * subsystem is set up, before kmalloc is valid) and during the 

 * dynamic lpar operation of adding a PHB to a running system.

 */

void __devinit pci_devs_phb_init_dynamic(struct pci_controller *phb)

{

	struct device_node * dn = (struct device_node *) phb->arch_data;
@@ -201,9 +209,14 @@ static struct notifier_block pci_dn_reconfig_nb = { 
	.notifier_call = pci_dn_reconfig_notifier,

};



/*

 * Actually initialize the phbs.

 * The buswalk on this phb has not happened yet.

/** 

 * pci_devs_phb_init - Initialize phbs and pci devs under them.

 * 

 * This routine walks over all phb's (pci-host bridges) on the

 * system, and sets up assorted pci-related structures 

 * (including pci info in the device node structs) for each

 * pci device found underneath.  This routine runs once,

 * early in the boot sequence.

 */

void __init pci_devs_phb_init(void)

{