linux/drivers/xen
Julien Grall 22f12f0df8 xen/events: events_fifo: Don't use {get,put}_cpu() in xen_evtchn_fifo_init()
When booting Linux as Xen guest with CONFIG_DEBUG_ATOMIC, the following
splat appears:

[    0.002323] Mountpoint-cache hash table entries: 1024 (order: 1, 8192 bytes)
[    0.019717] ASID allocator initialised with 65536 entries
[    0.020019] xen:grant_table: Grant tables using version 1 layout
[    0.020051] Grant table initialized
[    0.020069] BUG: sleeping function called from invalid context at /data/src/linux/mm/page_alloc.c:4046
[    0.020100] in_atomic(): 1, irqs_disabled(): 0, pid: 1, name: swapper/0
[    0.020123] no locks held by swapper/0/1.
[    0.020143] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.13.0-rc5 #598
[    0.020166] Hardware name: FVP Base (DT)
[    0.020182] Call trace:
[    0.020199] [<ffff00000808a5c0>] dump_backtrace+0x0/0x270
[    0.020222] [<ffff00000808a95c>] show_stack+0x24/0x30
[    0.020244] [<ffff000008c1ef20>] dump_stack+0xb8/0xf0
[    0.020267] [<ffff0000081128c0>] ___might_sleep+0x1c8/0x1f8
[    0.020291] [<ffff000008112948>] __might_sleep+0x58/0x90
[    0.020313] [<ffff0000082171b8>] __alloc_pages_nodemask+0x1c0/0x12e8
[    0.020338] [<ffff00000827a110>] alloc_page_interleave+0x38/0x88
[    0.020363] [<ffff00000827a904>] alloc_pages_current+0xdc/0xf0
[    0.020387] [<ffff000008211f38>] __get_free_pages+0x28/0x50
[    0.020411] [<ffff0000086566a4>] evtchn_fifo_alloc_control_block+0x2c/0xa0
[    0.020437] [<ffff0000091747b0>] xen_evtchn_fifo_init+0x38/0xb4
[    0.020461] [<ffff0000091746c0>] xen_init_IRQ+0x44/0xc8
[    0.020484] [<ffff000009128adc>] xen_guest_init+0x250/0x300
[    0.020507] [<ffff000008083974>] do_one_initcall+0x44/0x130
[    0.020531] [<ffff000009120df8>] kernel_init_freeable+0x120/0x288
[    0.020556] [<ffff000008c31ca8>] kernel_init+0x18/0x110
[    0.020578] [<ffff000008083710>] ret_from_fork+0x10/0x40
[    0.020606] xen:events: Using FIFO-based ABI
[    0.020658] Xen: initializing cpu0
[    0.027727] Hierarchical SRCU implementation.
[    0.036235] EFI services will not be available.
[    0.043810] smp: Bringing up secondary CPUs ...

This is because get_cpu() in xen_evtchn_fifo_init() will disable
preemption, but __get_free_page() might sleep (GFP_ATOMIC is not set).

xen_evtchn_fifo_init() will always be called before SMP is initialized,
so {get,put}_cpu() could be replaced by a simple smp_processor_id().

This also avoid to modify evtchn_fifo_alloc_control_block that will be
called in other context.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Reported-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Fixes: 1fe565517b ("xen/events: use the FIFO-based ABI if available")
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-08-31 09:45:55 -04:00
..
events xen/events: events_fifo: Don't use {get,put}_cpu() in xen_evtchn_fifo_init() 2017-08-31 09:45:55 -04:00
xen-pciback xen: modify xenstore watch event interface 2017-02-09 11:26:49 -05:00
xenbus xen: avoid deadlock in xenbus 2017-08-11 16:45:56 +02:00
xenfs xen: Drop un-informative message during boot 2017-07-27 19:55:34 +02:00
acpi.c xen: rename dom0_op to platform_op 2015-12-21 14:40:55 +00:00
arm-device.c Xen: ARM: Zero reserved fields of xatp before making hypervisor call 2017-01-03 10:06:13 -08:00
balloon.c xen/balloon: don't online new memory initially 2017-07-23 08:13:18 +02:00
biomerge.c xen/biomerge: Don't allow biovec's to be merged when Linux is not using 4KB pages 2015-10-23 14:20:36 +01:00
cpu_hotplug.c xen: modify xenstore watch event interface 2017-02-09 11:26:49 -05:00
dbgp.c xen: Use dev_is_pci() to check whether it is pci device 2014-01-07 09:53:33 -05:00
efi.c xen: Implement EFI reset_system callback 2017-05-02 12:06:50 +02:00
evtchn.c xen-evtchn: Bind dyn evtchn:qemu-dm interrupt to next online VCPU 2017-06-13 15:30:27 +02:00
fallback.c
features.c xen: audit usages of module.h ; remove unnecessary instances 2016-03-21 15:13:32 +00:00
gntalloc.c xen: set error code on failures 2016-12-08 07:53:50 +01:00
gntdev.c drivers, xen: convert grant_map.users from atomic_t to refcount_t 2017-03-13 12:45:18 -04:00
grant-table.c xen/grant-table: log the lack of grants 2017-07-23 08:09:43 +02:00
Kconfig xen: introduce a Kconfig option to enable the pvcalls backend 2017-08-31 09:45:55 -04:00
Makefile xen: introduce a Kconfig option to enable the pvcalls backend 2017-08-31 09:45:55 -04:00
manage.c xen: features and fixes for 4.13-rc1 2017-07-06 19:11:24 -07:00
mcelog.c x86/MCE, xen/mcelog: Make /dev/mcelog registration messages more precise 2017-06-20 23:25:19 +02:00
pci.c xen/pci: Try harder to get PXM information for Xen 2015-04-15 10:57:28 +01:00
pcpu.c xen: rename dom0_op to platform_op 2015-12-21 14:40:55 +00:00
platform-pci.c xen-platform: constify pci_device_id. 2017-08-31 09:45:55 -04:00
preempt.c xen/preempt: use need_resched() instead of should_resched() 2015-08-20 12:24:14 +01:00
privcmd.c xen/privcmd: Support correctly 64KB page granularity when mapping memory 2017-06-07 11:23:14 +02:00
privcmd.h
pvcalls-back.c xen/pvcalls: use WARN_ON(1) instead of __WARN() 2017-08-31 09:45:55 -04:00
swiotlb-xen.c xen-swiotlb: remove xen_swiotlb_set_dma_mask 2017-06-28 06:54:50 -07:00
sys-hypervisor.c xen: add sysfs node for hypervisor build id 2017-06-15 08:50:37 +02:00
time.c xen: add static initialization of steal_clock op to xen_time_ops 2016-07-26 14:07:06 +01:00
tmem.c fs: switch ->s_uuid to uuid_t 2017-06-05 16:59:12 +02:00
xen-acpi-cpuhotplug.c xen: rename dom0_op to platform_op 2015-12-21 14:40:55 +00:00
xen-acpi-memhotplug.c ACPICA: Resources: Provide common part for struct acpi_resource_address structures. 2015-01-26 16:09:56 +01:00
xen-acpi-pad.c xen: rename dom0_op to platform_op 2015-12-21 14:40:55 +00:00
xen-acpi-processor.c xen/acpi: upload PM state from init-domain to Xen 2017-03-23 12:00:02 -04:00
xen-balloon.c xen/balloon: don't online new memory initially 2017-07-23 08:13:18 +02:00
xen-scsiback.c xen/scsiback: Make TMF processing slightly faster 2017-07-06 22:58:03 -07:00
xen-selfballoon.c xen: selfballoon: remove unnecessary static in frontswap_selfshrink() 2017-07-27 19:55:41 +02:00
xen-stub.c
xlate_mmu.c Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn 2016-07-06 10:34:42 +01:00