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authorMichael Ellerman <mpe@ellerman.id.au>2015-04-24 15:52:32 +1000
committerDavid S. Miller <davem@davemloft.net>2015-04-25 14:33:04 -0400
commit3051f39253680624504021fd3b29fc621a4fd6b6 (patch)
treeef6fb8355c724f0ba1f9f18a5ee7f78b44e50d1a
parentdfc8f370316b31b9ca9ce96e50f1c438d9410b4f (diff)
ehea: Fix memory hook reference counting crashes
The recent commit to only register the EHEA memory hotplug hooks on adapter probe has a few problems. Firstly the reference counting is wrong for multiple adapters, in that the hooks are registered multiple times. Secondly the check in the tear down path is backward. Finally the error path doesn't decrement the count. The multiple registration of the hooks is the biggest problem, as it leads to oopses when the system is rebooted, and/or errors during memory hotplug, eg: $ ./mem-on-off-test.sh -r 2 ... ehea: memory is going offline ehea: LPAR memory changed - re-initializing driver ehea: re-initializing driver complete ehea: memory is going offline ehea: LPAR memory changed - re-initializing driver ehea: opcode=26c ret=fffffffffffffffc arg1=8000000003000003 arg2=0 arg3=700000060000d600 arg4=3fded0000 arg5=200 arg6=0 arg7=0 ehea: register_rpage_mr failed ehea: registering mr failed ehea: register MR failed - driver inoperable! ehea: memory is going offline Fixes: aa183323312d ("ehea: Register memory hotplug, reboot and crash hooks on adapter probe") Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/ethernet/ibm/ehea/ehea_main.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/net/ethernet/ibm/ehea/ehea_main.c b/drivers/net/ethernet/ibm/ehea/ehea_main.c
index 291c87036e17..2a0dc127df3f 100644
--- a/drivers/net/ethernet/ibm/ehea/ehea_main.c
+++ b/drivers/net/ethernet/ibm/ehea/ehea_main.c
@@ -3347,7 +3347,7 @@ static int ehea_register_memory_hooks(void)
{
int ret = 0;
- if (atomic_inc_and_test(&ehea_memory_hooks_registered))
+ if (atomic_inc_return(&ehea_memory_hooks_registered) > 1)
return 0;
ret = ehea_create_busmap();
@@ -3381,12 +3381,14 @@ out3:
out2:
unregister_reboot_notifier(&ehea_reboot_nb);
out:
+ atomic_dec(&ehea_memory_hooks_registered);
return ret;
}
static void ehea_unregister_memory_hooks(void)
{
- if (atomic_read(&ehea_memory_hooks_registered))
+ /* Only remove the hooks if we've registered them */
+ if (atomic_read(&ehea_memory_hooks_registered) == 0)
return;
unregister_reboot_notifier(&ehea_reboot_nb);