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authorPaolo Bonzini <pbonzini@redhat.com>2013-09-25 13:53:07 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2013-09-30 09:21:51 +0200
commit2f303b74a62fb74983c0a66e2df353be963c527c (patch)
tree430c287a89d709fb9d497d0c2a5a33acc434b020 /Documentation/virtual
parent4a937f96f3a29c58b7edd349d2e4dfac371efdf2 (diff)
downloadlinux-linaro-stable-2f303b74a62fb74983c0a66e2df353be963c527c.tar.gz
KVM: Convert kvm_lock back to non-raw spinlock
In commit e935b8372cf8 ("KVM: Convert kvm_lock to raw_spinlock"), the kvm_lock was made a raw lock. However, the kvm mmu_shrink() function tries to grab the (non-raw) mmu_lock within the scope of the raw locked kvm_lock being held. This leads to the following: BUG: sleeping function called from invalid context at kernel/rtmutex.c:659 in_atomic(): 1, irqs_disabled(): 0, pid: 55, name: kswapd0 Preemption disabled at:[<ffffffffa0376eac>] mmu_shrink+0x5c/0x1b0 [kvm] Pid: 55, comm: kswapd0 Not tainted 3.4.34_preempt-rt Call Trace: [<ffffffff8106f2ad>] __might_sleep+0xfd/0x160 [<ffffffff817d8d64>] rt_spin_lock+0x24/0x50 [<ffffffffa0376f3c>] mmu_shrink+0xec/0x1b0 [kvm] [<ffffffff8111455d>] shrink_slab+0x17d/0x3a0 [<ffffffff81151f00>] ? mem_cgroup_iter+0x130/0x260 [<ffffffff8111824a>] balance_pgdat+0x54a/0x730 [<ffffffff8111fe47>] ? set_pgdat_percpu_threshold+0xa7/0xd0 [<ffffffff811185bf>] kswapd+0x18f/0x490 [<ffffffff81070961>] ? get_parent_ip+0x11/0x50 [<ffffffff81061970>] ? __init_waitqueue_head+0x50/0x50 [<ffffffff81118430>] ? balance_pgdat+0x730/0x730 [<ffffffff81060d2b>] kthread+0xdb/0xe0 [<ffffffff8106e122>] ? finish_task_switch+0x52/0x100 [<ffffffff817e1e94>] kernel_thread_helper+0x4/0x10 [<ffffffff81060c50>] ? __init_kthread_worker+0x After the previous patch, kvm_lock need not be a raw spinlock anymore, so change it back. Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: kvm@vger.kernel.org Cc: gleb@redhat.com Cc: jan.kiszka@siemens.com Reviewed-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'Documentation/virtual')
-rw-r--r--Documentation/virtual/kvm/locking.txt2
1 files changed, 1 insertions, 1 deletions
diff --git a/Documentation/virtual/kvm/locking.txt b/Documentation/virtual/kvm/locking.txt
index ba9e1c2150c2..f8869410d40c 100644
--- a/Documentation/virtual/kvm/locking.txt
+++ b/Documentation/virtual/kvm/locking.txt
@@ -132,7 +132,7 @@ See the comments in spte_has_volatile_bits() and mmu_spte_update().
------------
Name: kvm_lock
-Type: raw_spinlock
+Type: spinlock_t
Arch: any
Protects: - vm_list