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openSUSE:12.2
xen
24690-x86-PCI-SERR-no-deadlock.patch
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File 24690-x86-PCI-SERR-no-deadlock.patch of Package xen
# HG changeset patch # User David Vrabel <david.vrabel@citrix.com> # Date 1328196538 0 # Node ID dcc6d57e4c07728693c685a2cfa7f094ef726267 # Parent 7091b2e4cc2cff07ad1bf24ba7b9506bae071fa8 x86: avoid deadlock after a PCI SERR NMI If a PCI System Error (SERR) is asserted it causes an NMI. If this NMI occurs while the CPU is in printk() then Xen may deadlock as pci_serr_error() calls console_force_unlock() which screws up the console lock. printk() isn't safe to call from NMI context so defer the diagnostic message to a softirq. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Tested-by: George Dunlap <george.dunlap@eu.citrix.com> Committed-by: Keir Fraser <keir@xen.org> --- a/xen/arch/x86/traps.c +++ b/xen/arch/x86/traps.c @@ -3137,6 +3137,11 @@ static void nmi_mce_softirq(void) st->vcpu = NULL; } +static void pci_serr_softirq(void) +{ + printk("\n\nNMI - PCI system error (SERR)\n"); +} + void async_exception_cleanup(struct vcpu *curr) { int trap; @@ -3223,10 +3228,11 @@ static void nmi_dom0_report(unsigned int static void pci_serr_error(struct cpu_user_regs *regs) { - console_force_unlock(); - printk("\n\nNMI - PCI system error (SERR)\n"); - outb((inb(0x61) & 0x0f) | 0x04, 0x61); /* clear-and-disable the PCI SERR error line. */ + + /* Would like to print a diagnostic here but can't call printk() + from NMI context -- raise a softirq instead. */ + raise_softirq(PCI_SERR_SOFTIRQ); } static void io_check_error(struct cpu_user_regs *regs) @@ -3529,6 +3535,7 @@ void __init trap_init(void) cpu_init(); open_softirq(NMI_MCE_SOFTIRQ, nmi_mce_softirq); + open_softirq(PCI_SERR_SOFTIRQ, pci_serr_softirq); } long register_guest_nmi_callback(unsigned long address) --- a/xen/include/asm-x86/softirq.h +++ b/xen/include/asm-x86/softirq.h @@ -6,6 +6,7 @@ #define VCPU_KICK_SOFTIRQ (NR_COMMON_SOFTIRQS + 2) #define MACHINE_CHECK_SOFTIRQ (NR_COMMON_SOFTIRQS + 3) -#define NR_ARCH_SOFTIRQS 4 +#define PCI_SERR_SOFTIRQ (NR_COMMON_SOFTIRQS + 4) +#define NR_ARCH_SOFTIRQS 5 #endif /* __ASM_SOFTIRQ_H__ */
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