Searched hist:"1 b23336a" (Results 1 – 1 of 1) sorted by relevance
| /openbmc/linux/lib/ |
| H A D | idr.c | 1b23336a Tue Mar 10 14:55:52 CDT 2009 Paul E. McKenney <paulmck@linux.vnet.ibm.com> idr: make idr_remove_all() do removal -before- free_layer()
Fix a problem in the IDR system, where an idr_remove_all() hands a data
element to call_rcu() (via free_layer()) before making that data element
inaccessible to new readers. This is very bad, and results in readers
still having a reference to this data element at the end of the grace
period.
Tests on large machines that concurrently map and unmap user-space memory
within the same multithreaded process result in crashes within about five
minutes. Applying this patch increases the kernel's longevity to the
three-to-eight-hour range.
There appear to be other similar problems in idr_get_empty_slot() and
sub_remove(), but I fixed the easy one in idr_remove_all() first. It is
therefore no surprise that failures still occur.
Located-by: Milton Miller II <miltonm@austin.ibm.com>
Tested-by: Milton Miller II <miltonm@austin.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1b23336a Tue Mar 10 14:55:52 CDT 2009 Paul E. McKenney <paulmck@linux.vnet.ibm.com> idr: make idr_remove_all() do removal -before- free_layer()
Fix a problem in the IDR system, where an idr_remove_all() hands a data
element to call_rcu() (via free_layer()) before making that data element
inaccessible to new readers. This is very bad, and results in readers
still having a reference to this data element at the end of the grace
period.
Tests on large machines that concurrently map and unmap user-space memory
within the same multithreaded process result in crashes within about five
minutes. Applying this patch increases the kernel's longevity to the
three-to-eight-hour range.
There appear to be other similar problems in idr_get_empty_slot() and
sub_remove(), but I fixed the easy one in idr_remove_all() first. It is
therefore no surprise that failures still occur.
Located-by: Milton Miller II <miltonm@austin.ibm.com>
Tested-by: Milton Miller II <miltonm@austin.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|