diff options
| author | Ross Lagerwall <ross.lagerwall@citrix.com> | 2016-03-17 16:52:00 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-05-11 11:21:15 +0200 |
| commit | 58d378b24b7f615b779ec20e7b7eebed8a3d8011 (patch) | |
| tree | 36f0f2936791cc14529278d64cf20277a5fce986 /drivers/xen | |
| parent | 0f7ea0699ac02fb7c5d67e8eac8f8581912f4988 (diff) | |
xen/balloon: Fix crash when ballooning on x86 32 bit PAE
commit dfd74a1edfaba5864276a2859190a8d242d18952 upstream.
Commit 55b3da98a40dbb3776f7454daf0d95dde25c33d2 (xen/balloon: find
non-conflicting regions to place hotplugged memory) caused a
regression in 4.4.
When ballooning on an x86 32 bit PAE system with close to 64 GiB of
memory, the address returned by allocate_resource may be above 64 GiB.
When using CONFIG_SPARSEMEM, this setup is limited to using physical
addresses < 64 GiB. When adding memory at this address, it runs off
the end of the mem_section array and causes a crash. Instead, fail
the ballooning request.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/xen')
| -rw-r--r-- | drivers/xen/balloon.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index 12eab503efd1..364bc44610c1 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -152,6 +152,8 @@ static DECLARE_WAIT_QUEUE_HEAD(balloon_wq); static void balloon_process(struct work_struct *work); static DECLARE_DELAYED_WORK(balloon_worker, balloon_process); +static void release_memory_resource(struct resource *resource); + /* When ballooning out (allocating memory to return to Xen) we don't really want the kernel to try too hard since that can trigger the oom killer. */ #define GFP_BALLOON \ @@ -268,6 +270,20 @@ static struct resource *additional_memory_resource(phys_addr_t size) return NULL; } +#ifdef CONFIG_SPARSEMEM + { + unsigned long limit = 1UL << (MAX_PHYSMEM_BITS - PAGE_SHIFT); + unsigned long pfn = res->start >> PAGE_SHIFT; + + if (pfn > limit) { + pr_err("New System RAM resource outside addressable RAM (%lu > %lu)\n", + pfn, limit); + release_memory_resource(res); + return NULL; + } + } +#endif + return res; } |