diff options
| author | Julien Grall | 2017-08-17 17:14:52 +0100 |
|---|---|---|
| committer | Boris Ostrovsky | 2017-08-31 09:45:55 -0400 |
| commit | 22f12f0df802cea865672d8f39fbebdc03981050 (patch) | |
| tree | 55272efd5acb862b225ce0d1e181395d73974cd6 | |
| parent | fefcfb9935be0208ff522563239f11a04f98c27d (diff) | |
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: 1fe565517b57 ("xen/events: use the FIFO-based ABI if available")
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
| -rw-r--r-- | drivers/xen/events/events_fifo.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c index 3c41470c7fc4..76b318e88382 100644 --- a/drivers/xen/events/events_fifo.c +++ b/drivers/xen/events/events_fifo.c @@ -432,12 +432,12 @@ static int xen_evtchn_cpu_dead(unsigned int cpu) int __init xen_evtchn_fifo_init(void) { - int cpu = get_cpu(); + int cpu = smp_processor_id(); int ret; ret = evtchn_fifo_alloc_control_block(cpu); if (ret < 0) - goto out; + return ret; pr_info("Using FIFO-based ABI\n"); @@ -446,7 +446,6 @@ int __init xen_evtchn_fifo_init(void) cpuhp_setup_state_nocalls(CPUHP_XEN_EVTCHN_PREPARE, "xen/evtchn:prepare", xen_evtchn_cpu_prepare, xen_evtchn_cpu_dead); -out: - put_cpu(); + return ret; } |