linux/arch/powerpc
Li Zhong e4f387d8db powerpc: Fix unpaired probe_hcall_entry and probe_hcall_exit
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>
CC: stable@kernel.org [v2.6.32+]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-01-03 12:09:27 +11:00
..
boot powerpc/boot: Change the WARN to INFO for boot wrapper overlap message 2011-12-21 15:09:25 -05:00
configs powerpc: Rename mapping based RELOCATABLE to DYNAMIC_MEMSTART for BookE 2011-12-20 10:20:19 -05:00
include/asm powerpc: Define virtual-physical translations for RELOCATABLE 2011-12-20 10:21:34 -05:00
kernel powerpc/44x: Enable CONFIG_RELOCATABLE for PPC44x 2011-12-20 10:21:57 -05:00
kvm powerpc: Provide a way for KVM to indicate that NV GPR values are lost 2011-12-08 14:22:53 +11:00
lib powerpc: POWER7 optimised copy_to_user/copy_from_user using VMX 2011-12-19 14:40:40 +11:00
math-emu powerpc/math_emu/efp: Look for errata handler when type mismatches 2011-10-06 23:36:47 -05:00
mm powerpc: Define virtual-physical translations for RELOCATABLE 2011-12-20 10:21:34 -05:00
net net: filter: BPF 'JIT' compiler for PPC64 2011-07-21 12:38:32 -07:00
oprofile powerpc/oprofile: Handle events that raise an exception without overflowing 2011-05-26 13:38:57 +10:00
platforms powerpc: Fix unpaired probe_hcall_entry and probe_hcall_exit 2012-01-03 12:09:27 +11:00
sysdev Merge remote-tracking branch 'jwb/next' into next 2011-12-16 11:24:25 +11:00
xmon powerpc/xmon: Fix #if typo for systems without MSR[RI] 2011-11-25 14:11:28 +11:00
Kconfig powerpc/44x: Enable CRASH_DUMP for 440x 2011-12-20 10:22:14 -05:00
Kconfig.debug powerpc: Implement CONFIG_STRICT_DEVMEM 2011-11-28 11:42:08 +11:00
Makefile powerpc: Process dynamic relocations for kernel 2011-12-20 10:21:08 -05:00
relocs_check.pl powerpc: Process dynamic relocations for kernel 2011-12-20 10:21:08 -05:00