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| author | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2013-03-19 14:35:30 -0400 |
|---|---|---|
| committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2013-03-22 08:23:11 -0400 |
| commit | 949dd8c14fb2b20b4b815817e66120b22cf531d4 (patch) | |
| tree | 3798bf25cfa052a89c95a732ce7c74face381182 /drivers/xen | |
| parent | d2e0bca377dc0f85acd19df465122f361a6c9e99 (diff) | |
| download | linux-949dd8c14fb2b20b4b815817e66120b22cf531d4.tar.bz2 | |
xen/acpi-processor: Don't dereference struct acpi_processor on all CPUs.
With git commit c705c78c0d0835a4aa5d0d9a3422e3218462030c
"acpi: Export the acpi_processor_get_performance_info" we are now
using a different mechanism to access the P-states.
The acpi_processor per-cpu structure is set and filtered by the
core ACPI code which shrinks the per_cpu contents to only online CPUs.
In the past we would call acpi_processor_register_performance()
which would have not tried to dereference offline cpus.
With the new patch and the fact that the loop we take is for
for_all_possible_cpus we end up crashing on some machines.
We could modify the loop to be for online_cpus - but all the other
loops in the code use possible_cpus (for a good reason) - so lets
leave it as so and just check if per_cpu(processor) is NULL.
With this patch we will bypass the !online but possible CPUs.
This fixes:
IP: [<ffffffffa00d13b5>] xen_acpi_processor_init+0x1b6/0xe01 [xen_acpi_processor]
PGD 4126e6067 PUD 4126e3067 PMD 0
Oops: 0002 [#1] SMP
Pid: 432, comm: modprobe Not tainted 3.9.0-rc3+ #28 To be filled by O.E.M. To be filled by O.E.M./M5A97
RIP: e030:[<ffffffffa00d13b5>] [<ffffffffa00d13b5>] xen_acpi_processor_init+0x1b6/0xe01 [xen_acpi_processor]
RSP: e02b:ffff88040c8a3ce8 EFLAGS: 00010282
.. snip..
Call Trace:
[<ffffffffa00d11ff>] ? read_acpi_id+0x12b/0x12b [xen_acpi_processor]
[<ffffffff8100215a>] do_one_initcall+0x12a/0x180
[<ffffffff810c42c3>] load_module+0x1cd3/0x2870
[<ffffffff81319b70>] ? ddebug_proc_open+0xc0/0xc0
[<ffffffff810c4f37>] sys_init_module+0xd7/0x120
[<ffffffff8166ce19>] system_call_fastpath+0x16/0x1b
on some machines.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers/xen')
| -rw-r--r-- | drivers/xen/xen-acpi-processor.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/xen/xen-acpi-processor.c b/drivers/xen/xen-acpi-processor.c index f3278a6603ca..90e34ac7e522 100644 --- a/drivers/xen/xen-acpi-processor.c +++ b/drivers/xen/xen-acpi-processor.c @@ -505,6 +505,9 @@ static int __init xen_acpi_processor_init(void) pr = per_cpu(processors, i); perf = per_cpu_ptr(acpi_perf_data, i); + if (!pr) + continue; + pr->performance = perf; rc = acpi_processor_get_performance_info(pr); if (rc) |