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c9438092ca
linux/arch/powerpc
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Paul Mackerras c9438092ca KVM: PPC: Book3S HV: Take SRCU read lock around kvm_read_guest() call 
Running a kernel with CONFIG_PROVE_RCU=y yields the following diagnostic:

===============================
[ INFO: suspicious RCU usage. ]
3.12.0-rc5-kvm+ #9 Not tainted
-------------------------------

include/linux/kvm_host.h:473 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 1, debug_locks = 0
1 lock held by qemu-system-ppc/4831:

stack backtrace:
CPU: 28 PID: 4831 Comm: qemu-system-ppc Not tainted 3.12.0-rc5-kvm+ #9
Call Trace:
[c000000be462b2a0] [c00000000001644c] .show_stack+0x7c/0x1f0 (unreliable)
[c000000be462b370] [c000000000ad57c0] .dump_stack+0x88/0xb4
[c000000be462b3f0] [c0000000001315e8] .lockdep_rcu_suspicious+0x138/0x180
[c000000be462b480] [c00000000007862c] .gfn_to_memslot+0x13c/0x170
[c000000be462b510] [c00000000007d384] .gfn_to_hva_prot+0x24/0x90
[c000000be462b5a0] [c00000000007d420] .kvm_read_guest_page+0x30/0xd0
[c000000be462b630] [c00000000007d528] .kvm_read_guest+0x68/0x110
[c000000be462b6e0] [c000000000084594] .kvmppc_rtas_hcall+0x34/0x180
[c000000be462b7d0] [c000000000097934] .kvmppc_pseries_do_hcall+0x74/0x830
[c000000be462b880] [c0000000000990e8] .kvmppc_vcpu_run_hv+0xff8/0x15a0
[c000000be462b9e0] [c0000000000839cc] .kvmppc_vcpu_run+0x2c/0x40
[c000000be462ba50] [c0000000000810b4] .kvm_arch_vcpu_ioctl_run+0x54/0x1b0
[c000000be462bae0] [c00000000007b508] .kvm_vcpu_ioctl+0x478/0x730
[c000000be462bca0] [c00000000025532c] .do_vfs_ioctl+0x4dc/0x7a0
[c000000be462bd80] [c0000000002556b4] .SyS_ioctl+0xc4/0xe0
[c000000be462be30] [c000000000009ee4] syscall_exit+0x0/0x98

To fix this, we take the SRCU read lock around the kvmppc_rtas_hcall()
call.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-11-18 22:41:20 +01:00
..
boot powerpc/boot: Properly handle the base "of" boot wrapper 2013-11-05 10:09:11 +11:00
configs powerpc: Enable virtio on ppc64 and pseries configs 2013-10-30 16:02:09 +11:00
crypto
include Here are the 3.13 KVM changes. There was a lot of work on the PPC 2013-11-15 13:51:36 +09:00
kernel Here are the 3.13 KVM changes. There was a lot of work on the PPC 2013-11-15 13:51:36 +09:00
kvm KVM: PPC: Book3S HV: Take SRCU read lock around kvm_read_guest() call 2013-11-18 22:41:20 +01:00
lib powerpc: Add VMX optimised xor for RAID5 2013-10-30 16:02:28 +11:00
math-emu powerpc/math-emu: Fix load/store indexed emulation 2013-08-14 14:59:57 +10:00
mm powerpc: handle pgtable_page_ctor() fail 2013-11-15 09:32:18 +09:00
net Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc 2013-11-12 14:34:19 +09:00
oprofile Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc 2013-09-06 10:49:42 -07:00
perf powerpc/perf: Fix handling of FAB events 2013-10-03 17:25:38 +10:00
platforms tree-wide: use reinit_completion instead of INIT_COMPLETION 2013-11-15 09:32:21 +09:00
sysdev PCI changes for the v3.13 merge window: 2013-11-14 14:02:00 +09:00
xmon powerpc/xmon: Fix printing of set of CPUs in xmon 2013-09-05 17:29:19 +10:00
Kconfig kernel: remove CONFIG_USE_GENERIC_SMP_HELPERS 2013-11-15 09:32:22 +09:00
Kconfig.debug
Makefile powerpc: Work around little endian gcc bug 2013-10-11 16:48:57 +11:00
relocs_check.pl