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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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38a2ba82e2
commit c749d8c018daf5fba6dfac7b6c5c78b27efd7d65 upstream.
Currently css_wait_for_slow_path() gets called inside the chp->lock.
The path-verification-loop of slowpath inside this lock could lead to
deadlock as reported by the lockdep validator.
The ccw_device_get_chp_desc() during the instance of a device-set-online
would try to acquire the same 'chp->lock' to read the chp->desc.
The instance of this function can get called from multiple scenario,
like probing or setting-device online manually. This could, in some
corner-cases lead to the deadlock.
lockdep validator reported this as,
CPU0 CPU1
---- ----
lock(&chp->lock);
lock(kn->active#43);
lock(&chp->lock);
lock((wq_completion)cio);
The chp->lock was introduced to serialize the access of struct
channel_path. This lock is not needed for the css_wait_for_slow_path()
function, so invoke the slow-path function outside this lock.
Fixes:
|
||
|---|---|---|
| .. | ||
| airq.c | ||
| blacklist.c | ||
| blacklist.h | ||
| ccwgroup.c | ||
| ccwreq.c | ||
| chp.c | ||
| chp.h | ||
| chsc_sch.c | ||
| chsc_sch.h | ||
| chsc.c | ||
| chsc.h | ||
| cio_debug.h | ||
| cio.c | ||
| cio.h | ||
| cmf.c | ||
| crw.c | ||
| css.c | ||
| css.h | ||
| device_fsm.c | ||
| device_id.c | ||
| device_ops.c | ||
| device_pgid.c | ||
| device_status.c | ||
| device.c | ||
| device.h | ||
| eadm_sch.c | ||
| eadm_sch.h | ||
| fcx.c | ||
| idset.c | ||
| idset.h | ||
| io_sch.h | ||
| ioasm.c | ||
| ioasm.h | ||
| isc.c | ||
| itcw.c | ||
| Makefile | ||
| orb.h | ||
| qdio_debug.c | ||
| qdio_debug.h | ||
| qdio_main.c | ||
| qdio_setup.c | ||
| qdio_thinint.c | ||
| qdio.h | ||
| scm.c | ||
| trace.c | ||
| trace.h | ||
| vfio_ccw_async.c | ||
| vfio_ccw_chp.c | ||
| vfio_ccw_cp.c | ||
| vfio_ccw_cp.h | ||
| vfio_ccw_drv.c | ||
| vfio_ccw_fsm.c | ||
| vfio_ccw_ops.c | ||
| vfio_ccw_private.h | ||
| vfio_ccw_trace.c | ||
| vfio_ccw_trace.h | ||