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| author |   Ursula Braun <braunu@de.ibm.com> | 2007-07-14 19:03:41 -0700 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2007-07-14 19:03:41 -0700 |
| commit | 13fdc9a74df0fec70f421c6891e184ed8c3b9088 (patch) | |
| tree | efd81d0f35e2300ee86e538fa8c136654c7c0dae /net/iucv/iucv.c | |
| parent | [AF_IUCV]: Improve description of IUCV and AFIUCV configuration options. (diff) | |
| download | linux-dev-13fdc9a74df0fec70f421c6891e184ed8c3b9088.tar.xz linux-dev-13fdc9a74df0fec70f421c6891e184ed8c3b9088.zip | |
[AF_IUCV]: Avoid deadlock between iucv_path_connect and tasklet.
An iucv deadlock may occur, where one CPU is spinning on the
iucv_table_lock for iucv_tasklet_fn(), while another CPU is holding
the iucv_table_lock for an iucv_path_connect() and is waiting for
the first CPU in an smp_call_function.
Solution: replace spin_lock in iucv_tasklet_fn by spin_trylock and
reschedule tasklet in case of non-granted lock.
Signed-off-by: Ursula Braun <braunu@de.ibm.com>
Acked-by: Frank Pavlic <fpavlic@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/iucv/iucv.c')
| -rw-r--r-- | net/iucv/iucv.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/net/iucv/iucv.c b/net/iucv/iucv.c index b7333061016d..ad5150b8dfa9 100644 --- a/net/iucv/iucv.c +++ b/net/iucv/iucv.c @@ -1494,7 +1494,10 @@ static void iucv_tasklet_fn(unsigned long ignored) struct iucv_irq_list *p, *n; /* Serialize tasklet, iucv_path_sever and iucv_path_connect. */ - spin_lock(&iucv_table_lock); + if (!spin_trylock(&iucv_table_lock)) { + tasklet_schedule(&iucv_tasklet); + return; + } iucv_active_cpu = smp_processor_id(); spin_lock_irq(&iucv_queue_lock); |