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authorLi Zhong <zhong@linux.vnet.ibm.com>2011-12-18 16:03:04 +0000
committerGreg Kroah-Hartman <gregkh@suse.de>2012-01-12 11:29:23 -0800
commitddcf85d72ffe4fd46239a94253fe04c114d4d1e2 (patch)
treee4da65c4289f3d529ac4c6e1f752e6dbbd1ebfd8 /drivers
parent8e04782a06882913304916bc60960e4fc7405e18 (diff)
downloadvexpress-lsk-ddcf85d72ffe4fd46239a94253fe04c114d4d1e2.tar.gz
powerpc: Fix unpaired probe_hcall_entry and probe_hcall_exit
commit e4f387d8db3ba3c2dae4d8bdfe7bb5f4fe1bcb0d upstream. Unpaired calling of probe_hcall_entry and probe_hcall_exit might happen as following, which could cause incorrect preempt count. __trace_hcall_entry => trace_hcall_entry -> probe_hcall_entry => get_cpu_var => preempt_disable __trace_hcall_exit => trace_hcall_exit -> probe_hcall_exit => put_cpu_var => preempt_enable where: A => B and A -> B means A calls B, but => means A will call B through function name, and B will definitely be called. -> means A will call B through function pointer, so B might not be called if the function pointer is not set. So error happens when only one of probe_hcall_entry and probe_hcall_exit get called during a hcall. This patch tries to move the preempt count operations from probe_hcall_entry and probe_hcall_exit to its callers. Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
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