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authorChristian Borntraeger <borntraeger@de.ibm.com>2011-12-27 11:25:47 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2011-12-27 11:25:48 +0100
commitc86cce2a20207cbf2b3dfe97c985a1f5aa5d3798 (patch)
treeccfd31096b52184cf393a3da8813b7b728157c81 /arch/s390/mm
parent1fb810576f0e92451a5d46774bbd593946ca3526 (diff)
downloadlinux-linaro-stable-c86cce2a20207cbf2b3dfe97c985a1f5aa5d3798.tar.gz
[S390] kvm: fix sleeping function ... at mm/page_alloc.c:2260
commit cc772456ac9b460693492b3a3d89e8c81eda5874 [S390] fix list corruption in gmap reverse mapping added a potential dead lock: BUG: sleeping function called from invalid context at mm/page_alloc.c:2260 in_atomic(): 1, irqs_disabled(): 0, pid: 1108, name: qemu-system-s39 3 locks held by qemu-system-s39/1108: #0: (&kvm->slots_lock){+.+.+.}, at: [<000003e004866542>] kvm_set_memory_region+0x3a/0x6c [kvm] #1: (&mm->mmap_sem){++++++}, at: [<0000000000123790>] gmap_map_segment+0x9c/0x298 #2: (&(&mm->page_table_lock)->rlock){+.+.+.}, at: [<00000000001237a8>] gmap_map_segment+0xb4/0x298 CPU: 0 Not tainted 3.1.3 #45 Process qemu-system-s39 (pid: 1108, task: 00000004f8b3cb30, ksp: 00000004fd5978d0) 00000004fd5979a0 00000004fd597920 0000000000000002 0000000000000000 00000004fd5979c0 00000004fd597938 00000004fd597938 0000000000617e96 0000000000000000 00000004f8b3cf58 0000000000000000 0000000000000000 000000000000000d 000000000000000c 00000004fd597988 0000000000000000 0000000000000000 0000000000100a18 00000004fd597920 00000004fd597960 Call Trace: ([<0000000000100926>] show_trace+0xee/0x144) [<0000000000131f3a>] __might_sleep+0x12a/0x158 [<0000000000217fb4>] __alloc_pages_nodemask+0x224/0xadc [<0000000000123086>] gmap_alloc_table+0x46/0x114 [<000000000012395c>] gmap_map_segment+0x268/0x298 [<000003e00486b014>] kvm_arch_commit_memory_region+0x44/0x6c [kvm] [<000003e004866414>] __kvm_set_memory_region+0x3b0/0x4a4 [kvm] [<000003e004866554>] kvm_set_memory_region+0x4c/0x6c [kvm] [<000003e004867c7a>] kvm_vm_ioctl+0x14a/0x314 [kvm] [<0000000000292100>] do_vfs_ioctl+0x94/0x588 [<0000000000292688>] SyS_ioctl+0x94/0xac [<000000000061e124>] sysc_noemu+0x22/0x28 [<000003fffcd5e7ca>] 0x3fffcd5e7ca 3 locks held by qemu-system-s39/1108: #0: (&kvm->slots_lock){+.+.+.}, at: [<000003e004866542>] kvm_set_memory_region+0x3a/0x6c [kvm] #1: (&mm->mmap_sem){++++++}, at: [<0000000000123790>] gmap_map_segment+0x9c/0x298 #2: (&(&mm->page_table_lock)->rlock){+.+.+.}, at: [<00000000001237a8>] gmap_map_segment+0xb4/0x298 Fix this by freeing the lock on the alloc path. This is ok, since the gmap table is never freed until we call gmap_free, so the table we are walking cannot go. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/mm')
-rw-r--r--arch/s390/mm/pgtable.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 301c84d3b542..dc2269f1821c 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -267,7 +267,10 @@ static int gmap_alloc_table(struct gmap *gmap,
struct page *page;
unsigned long *new;
+ /* since we dont free the gmap table until gmap_free we can unlock */
+ spin_unlock(&gmap->mm->page_table_lock);
page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
+ spin_lock(&gmap->mm->page_table_lock);
if (!page)
return -ENOMEM;
new = (unsigned long *) page_to_phys(page);