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authorMike Marciniszyn <mike.marciniszyn@intel.com>2013-05-17 12:40:32 +0000
committerRoland Dreier <roland@purestorage.com>2013-06-04 17:05:20 -0700
commitf3bdf34465307fc3f6967a9202a921e11505b2e6 (patch)
tree17bdd2949ab8f7e37f66debf38beb4e21756764c /drivers/infiniband
parentd683b96b072dc4680fc74964eca77e6a23d1fa6e (diff)
downloadlinux-linaro-stable-f3bdf34465307fc3f6967a9202a921e11505b2e6.tar.gz
IB/qib: Fix lockdep splat in qib_alloc_lkey()
The following backtrace is reported with CONFIG_PROVE_RCU: drivers/infiniband/hw/qib/qib_keys.c:64 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 1 4 locks held by kworker/0:1/56: #0: (events){.+.+.+}, at: [<ffffffff8107a4f5>] process_one_work+0x165/0x4a0 #1: ((&wfc.work)){+.+.+.}, at: [<ffffffff8107a4f5>] process_one_work+0x165/0x4a0 #2: (device_mutex){+.+.+.}, at: [<ffffffffa0148dd8>] ib_register_device+0x38/0x220 [ib_core] #3: (&(&dev->lk_table.lock)->rlock){......}, at: [<ffffffffa017e81c>] qib_alloc_lkey+0x3c/0x1b0 [ib_qib] stack backtrace: Pid: 56, comm: kworker/0:1 Not tainted 3.10.0-rc1+ #6 Call Trace: [<ffffffff810c0b85>] lockdep_rcu_suspicious+0xe5/0x130 [<ffffffffa017e8e1>] qib_alloc_lkey+0x101/0x1b0 [ib_qib] [<ffffffffa0184886>] qib_get_dma_mr+0xa6/0xd0 [ib_qib] [<ffffffffa01461aa>] ib_get_dma_mr+0x1a/0x50 [ib_core] [<ffffffffa01678dc>] ib_mad_port_open+0x12c/0x390 [ib_mad] [<ffffffff810c2c55>] ? trace_hardirqs_on_caller+0x105/0x190 [<ffffffffa0167b92>] ib_mad_init_device+0x52/0x110 [ib_mad] [<ffffffffa01917c0>] ? sl2vl_attr_show+0x30/0x30 [ib_qib] [<ffffffffa0148f49>] ib_register_device+0x1a9/0x220 [ib_core] [<ffffffffa01b1685>] qib_register_ib_device+0x735/0xa40 [ib_qib] [<ffffffff8106ba98>] ? mod_timer+0x118/0x220 [<ffffffffa017d425>] qib_init_one+0x1e5/0x400 [ib_qib] [<ffffffff812ce86e>] local_pci_probe+0x4e/0x90 [<ffffffff81078118>] work_for_cpu_fn+0x18/0x30 [<ffffffff8107a566>] process_one_work+0x1d6/0x4a0 [<ffffffff8107a4f5>] ? process_one_work+0x165/0x4a0 [<ffffffff8107c9c9>] worker_thread+0x119/0x370 [<ffffffff8107c8b0>] ? manage_workers+0x180/0x180 [<ffffffff8108294e>] kthread+0xee/0x100 [<ffffffff81082860>] ? __init_kthread_worker+0x70/0x70 [<ffffffff815c04ac>] ret_from_fork+0x7c/0xb0 [<ffffffff81082860>] ? __init_kthread_worker+0x70/0x70 Per Documentation/RCU/lockdep-splat.txt, the code now uses rcu_access_pointer() vs. rcu_dereference(). Reported-by: Jay Fenlason <fenlason@redhat.com> Reviewed-by: Dean Luick <dean.luick@intel.com> Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com> Signed-off-by: Roland Dreier <roland@purestorage.com>
Diffstat (limited to 'drivers/infiniband')
-rw-r--r--drivers/infiniband/hw/qib/qib_keys.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/infiniband/hw/qib/qib_keys.c b/drivers/infiniband/hw/qib/qib_keys.c
index 81c7b73695d2..3b9afccaaade 100644
--- a/drivers/infiniband/hw/qib/qib_keys.c
+++ b/drivers/infiniband/hw/qib/qib_keys.c
@@ -61,7 +61,7 @@ int qib_alloc_lkey(struct qib_mregion *mr, int dma_region)
if (dma_region) {
struct qib_mregion *tmr;
- tmr = rcu_dereference(dev->dma_mr);
+ tmr = rcu_access_pointer(dev->dma_mr);
if (!tmr) {
qib_get_mr(mr);
rcu_assign_pointer(dev->dma_mr, mr);