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author | Li Zhong <zhong@linux.vnet.ibm.com> | 2011-12-18 16:03:04 +0000 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2012-01-12 11:29:23 -0800 |
commit | ddcf85d72ffe4fd46239a94253fe04c114d4d1e2 (patch) | |
tree | e4da65c4289f3d529ac4c6e1f752e6dbbd1ebfd8 /drivers | |
parent | 8e04782a06882913304916bc60960e4fc7405e18 (diff) |
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')
0 files changed, 0 insertions, 0 deletions