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4ea9b9aca9
On x2apic enabled pvm, doing sysrq+l, got NULL pointer dereference as below.
SysRq : Show backtrace of all active CPUs
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffff8125e3cb>] memcpy+0xb/0x120
Call Trace:
[<ffffffff81039633>] ? __x2apic_send_IPI_mask+0x73/0x160
[<ffffffff8103973e>] x2apic_send_IPI_all+0x1e/0x20
[<ffffffff8103498c>] arch_trigger_all_cpu_backtrace+0x6c/0xb0
[<ffffffff81501be4>] ? _raw_spin_lock_irqsave+0x34/0x50
[<ffffffff8131654e>] sysrq_handle_showallcpus+0xe/0x10
[<ffffffff8131616d>] __handle_sysrq+0x7d/0x140
[<ffffffff81316230>] ? __handle_sysrq+0x140/0x140
[<ffffffff81316287>] write_sysrq_trigger+0x57/0x60
[<ffffffff811ca996>] proc_reg_write+0x86/0xc0
[<ffffffff8116dd8e>] vfs_write+0xce/0x190
[<ffffffff8116e3e5>] sys_write+0x55/0x90
[<ffffffff8150a242>] system_call_fastpath+0x16/0x1b
That's because apic points to apic_x2apic_cluster or apic_x2apic_phys
but the basic element like cpumask isn't initialized.
Mask x2APIC feature in pvm to avoid overwrite of apic pointer,
update commit message per Konrad's suggestion.
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Tested-by: Tamon Shiose <tamon.shiose@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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|---|---|---|
| .. | ||
| apic.c | ||
| debugfs.c | ||
| debugfs.h | ||
| enlighten.c | ||
| grant-table.c | ||
| irq.c | ||
| Kconfig | ||
| Makefile | ||
| mmu.c | ||
| mmu.h | ||
| multicalls.c | ||
| multicalls.h | ||
| p2m.c | ||
| pci-swiotlb-xen.c | ||
| platform-pci-unplug.c | ||
| setup.c | ||
| smp.c | ||
| smp.h | ||
| spinlock.c | ||
| suspend.c | ||
| time.c | ||
| trace.c | ||
| vdso.h | ||
| vga.c | ||
| xen-asm_32.S | ||
| xen-asm_64.S | ||
| xen-asm.h | ||
| xen-asm.S | ||
| xen-head.S | ||
| xen-ops.h | ||