Re: [PATCH] KVM: PPC: Book3S HV: Skip kvmppc_uvmem_free if Ultravisor is not supported
On Thu, Mar 19, 2020 at 07:55:10PM -0300, Fabiano Rosas wrote:
> kvmppc_uvmem_init checks for Ultravisor support and returns early if
> it is not present. Calling kvmppc_uvmem_free at module exit will cause
> an Oops:
>
> $ modprobe -r kvm-hv
>
> Oops: Kernel access of bad area, sig: 11 [#1]
>
> NIP: c0789e90 LR: c0789e8c CTR: c0401030
> REGS: c03fa7bab9a0 TRAP: 0300 Not tainted
> (5.6.0-rc6-00033-g6c90b86a745a-dirty)
> MSR: 90009033 CR: 24002282 XER:
>
> CFAR: c0dae880 DAR: 0008 DSISR: 4000 IRQMASK: 1
> GPR00: c0789e8c c03fa7babc30 c16fe500
> GPR04: 0006 c03faf205c00
> GPR08: 0001 802d c0080ddde140
> GPR12: c0401030 c03d9080 0001
> GPR16: 00013aad0074 00013aaac978
> GPR20: 00013aad0070 7fffd1b37158
> GPR24: 00014fef0d58 00014fef0cf0 0001
> GPR28: c18b2a60
> NIP [c0789e90] percpu_ref_kill_and_confirm+0x40/0x170
> LR [c0789e8c] percpu_ref_kill_and_confirm+0x3c/0x170
> Call Trace:
> [c03fa7babc30] [c03faf2064d4] 0xc03faf2064d4 (unreliable)
> [c03fa7babcb0] [c0400e8c] dev_pagemap_kill+0x6c/0x80
> [c03fa7babcd0] [c0401064] memunmap_pages+0x34/0x2f0
> [c03fa7babd50] [c0080548] kvmppc_uvmem_free+0x30/0x80 [kvm_hv]
> [c03fa7babd80] [c0080ddcef18] kvmppc_book3s_exit_hv+0x20/0x78
> [kvm_hv]
> [c03fa7babda0] [c02084d0] sys_delete_module+0x1d0/0x2c0
> [c03fa7babe20] [c000b9d0] system_call+0x5c/0x68
> Instruction dump:
> 3fc2001b fb81ffe0 fba1ffe8 fbe1fff8 7c7f1b78 7c9c2378 3bde4560 7fc3f378
> f8010010 f821ff81 486249a1 6000 7c7d1b78 712a0002 40820084
> ---[ end trace 5774ef4dc2c98279 ]---
>
> So this patch checks if kvmppc_uvmem_init actually allocated anything
> before running kvmppc_uvmem_free.
>
> Fixes: ca9f4942670c ("KVM: PPC: Book3S HV: Support for running secure guests")
> Reported-by: Greg Kurz
> Signed-off-by: Fabiano Rosas
Thanks, applied to my kvm-ppc-next branch (Michael Ellerman decided
that he didn't need to take it as the crash only occurs with
CONFIG_PPC_UV=n, which is not the default).
Paul.
Re: [PATCH] KVM: PPC: Book3S HV: Skip kvmppc_uvmem_free if Ultravisor is not supported
On Thu, 19 Mar 2020 19:55:10 -0300
Fabiano Rosas wrote:
> kvmppc_uvmem_init checks for Ultravisor support and returns early if
> it is not present. Calling kvmppc_uvmem_free at module exit will cause
> an Oops:
>
> $ modprobe -r kvm-hv
>
> Oops: Kernel access of bad area, sig: 11 [#1]
>
> NIP: c0789e90 LR: c0789e8c CTR: c0401030
> REGS: c03fa7bab9a0 TRAP: 0300 Not tainted
> (5.6.0-rc6-00033-g6c90b86a745a-dirty)
> MSR: 90009033 CR: 24002282 XER:
>
> CFAR: c0dae880 DAR: 0008 DSISR: 4000 IRQMASK: 1
> GPR00: c0789e8c c03fa7babc30 c16fe500
> GPR04: 0006 c03faf205c00
> GPR08: 0001 802d c0080ddde140
> GPR12: c0401030 c03d9080 0001
> GPR16: 00013aad0074 00013aaac978
> GPR20: 00013aad0070 7fffd1b37158
> GPR24: 00014fef0d58 00014fef0cf0 0001
> GPR28: c18b2a60
> NIP [c0789e90] percpu_ref_kill_and_confirm+0x40/0x170
> LR [c0789e8c] percpu_ref_kill_and_confirm+0x3c/0x170
> Call Trace:
> [c03fa7babc30] [c03faf2064d4] 0xc03faf2064d4 (unreliable)
> [c03fa7babcb0] [c0400e8c] dev_pagemap_kill+0x6c/0x80
> [c03fa7babcd0] [c0401064] memunmap_pages+0x34/0x2f0
> [c03fa7babd50] [c0080548] kvmppc_uvmem_free+0x30/0x80 [kvm_hv]
> [c03fa7babd80] [c0080ddcef18] kvmppc_book3s_exit_hv+0x20/0x78
> [kvm_hv]
> [c03fa7babda0] [c02084d0] sys_delete_module+0x1d0/0x2c0
> [c03fa7babe20] [c000b9d0] system_call+0x5c/0x68
> Instruction dump:
> 3fc2001b fb81ffe0 fba1ffe8 fbe1fff8 7c7f1b78 7c9c2378 3bde4560 7fc3f378
> f8010010 f821ff81 486249a1 6000 7c7d1b78 712a0002 40820084
> ---[ end trace 5774ef4dc2c98279 ]---
>
> So this patch checks if kvmppc_uvmem_init actually allocated anything
> before running kvmppc_uvmem_free.
>
> Fixes: ca9f4942670c ("KVM: PPC: Book3S HV: Support for running secure guests")
> Reported-by: Greg Kurz
> Signed-off-by: Fabiano Rosas
> ---
Thanks for the quick fix :)
Tested-by: Greg Kurz
> arch/powerpc/kvm/book3s_hv_uvmem.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c
> b/arch/powerpc/kvm/book3s_hv_uvmem.c
> index 79b1202b1c62..9d26614b2a77 100644
> --- a/arch/powerpc/kvm/book3s_hv_uvmem.c
> +++ b/arch/powerpc/kvm/book3s_hv_uvmem.c
> @@ -806,6 +806,9 @@ int kvmppc_uvmem_init(void)
>
> void kvmppc_uvmem_free(void)
> {
> + if (!kvmppc_uvmem_bitmap)
> + return;
> +
> memunmap_pages(_uvmem_pgmap);
> release_mem_region(kvmppc_uvmem_pgmap.res.start,
> resource_size(_uvmem_pgmap.res));
Re: [PATCH] KVM: PPC: Book3S HV: Skip kvmppc_uvmem_free if Ultravisor is not supported
On Thu, Mar 19, 2020 at 07:55:10PM -0300, Fabiano Rosas wrote:
> kvmppc_uvmem_init checks for Ultravisor support and returns early if
> it is not present. Calling kvmppc_uvmem_free at module exit will cause
> an Oops:
>
> $ modprobe -r kvm-hv
>
> Oops: Kernel access of bad area, sig: 11 [#1]
>
> NIP: c0789e90 LR: c0789e8c CTR: c0401030
> REGS: c03fa7bab9a0 TRAP: 0300 Not tainted
> (5.6.0-rc6-00033-g6c90b86a745a-dirty)
> MSR: 90009033 CR: 24002282 XER:
>
> CFAR: c0dae880 DAR: 0008 DSISR: 4000 IRQMASK: 1
> GPR00: c0789e8c c03fa7babc30 c16fe500
> GPR04: 0006 c03faf205c00
> GPR08: 0001 802d c0080ddde140
> GPR12: c0401030 c03d9080 0001
> GPR16: 00013aad0074 00013aaac978
> GPR20: 00013aad0070 7fffd1b37158
> GPR24: 00014fef0d58 00014fef0cf0 0001
> GPR28: c18b2a60
> NIP [c0789e90] percpu_ref_kill_and_confirm+0x40/0x170
> LR [c0789e8c] percpu_ref_kill_and_confirm+0x3c/0x170
> Call Trace:
> [c03fa7babc30] [c03faf2064d4] 0xc03faf2064d4 (unreliable)
> [c03fa7babcb0] [c0400e8c] dev_pagemap_kill+0x6c/0x80
> [c03fa7babcd0] [c0401064] memunmap_pages+0x34/0x2f0
> [c03fa7babd50] [c0080548] kvmppc_uvmem_free+0x30/0x80 [kvm_hv]
> [c03fa7babd80] [c0080ddcef18] kvmppc_book3s_exit_hv+0x20/0x78
> [kvm_hv]
> [c03fa7babda0] [c02084d0] sys_delete_module+0x1d0/0x2c0
> [c03fa7babe20] [c000b9d0] system_call+0x5c/0x68
> Instruction dump:
> 3fc2001b fb81ffe0 fba1ffe8 fbe1fff8 7c7f1b78 7c9c2378 3bde4560 7fc3f378
> f8010010 f821ff81 486249a1 6000 7c7d1b78 712a0002 40820084
> ---[ end trace 5774ef4dc2c98279 ]---
>
> So this patch checks if kvmppc_uvmem_init actually allocated anything
> before running kvmppc_uvmem_free.
>
> Fixes: ca9f4942670c ("KVM: PPC: Book3S HV: Support for running secure guests")
> Reported-by: Greg Kurz
> Signed-off-by: Fabiano Rosas
Good catch!
This should be Cc: sta...@vger.kernel.org # v5.5+
Acked-by: Paul Mackerras
Paul.
[PATCH] KVM: PPC: Book3S HV: Skip kvmppc_uvmem_free if Ultravisor is not supported
kvmppc_uvmem_init checks for Ultravisor support and returns early if
it is not present. Calling kvmppc_uvmem_free at module exit will cause
an Oops:
$ modprobe -r kvm-hv
Oops: Kernel access of bad area, sig: 11 [#1]
NIP: c0789e90 LR: c0789e8c CTR: c0401030
REGS: c03fa7bab9a0 TRAP: 0300 Not tainted
(5.6.0-rc6-00033-g6c90b86a745a-dirty)
MSR: 90009033 CR: 24002282 XER:
CFAR: c0dae880 DAR: 0008 DSISR: 4000 IRQMASK: 1
GPR00: c0789e8c c03fa7babc30 c16fe500
GPR04: 0006 c03faf205c00
GPR08: 0001 802d c0080ddde140
GPR12: c0401030 c03d9080 0001
GPR16: 00013aad0074 00013aaac978
GPR20: 00013aad0070 7fffd1b37158
GPR24: 00014fef0d58 00014fef0cf0 0001
GPR28: c18b2a60
NIP [c0789e90] percpu_ref_kill_and_confirm+0x40/0x170
LR [c0789e8c] percpu_ref_kill_and_confirm+0x3c/0x170
Call Trace:
[c03fa7babc30] [c03faf2064d4] 0xc03faf2064d4 (unreliable)
[c03fa7babcb0] [c0400e8c] dev_pagemap_kill+0x6c/0x80
[c03fa7babcd0] [c0401064] memunmap_pages+0x34/0x2f0
[c03fa7babd50] [c0080548] kvmppc_uvmem_free+0x30/0x80 [kvm_hv]
[c03fa7babd80] [c0080ddcef18] kvmppc_book3s_exit_hv+0x20/0x78 [kvm_hv]
[c03fa7babda0] [c02084d0] sys_delete_module+0x1d0/0x2c0
[c03fa7babe20] [c000b9d0] system_call+0x5c/0x68
Instruction dump:
3fc2001b fb81ffe0 fba1ffe8 fbe1fff8 7c7f1b78 7c9c2378 3bde4560 7fc3f378
f8010010 f821ff81 486249a1 6000 7c7d1b78 712a0002 40820084
---[ end trace 5774ef4dc2c98279 ]---
So this patch checks if kvmppc_uvmem_init actually allocated anything
before running kvmppc_uvmem_free.
Fixes: ca9f4942670c ("KVM: PPC: Book3S HV: Support for running secure guests")
Reported-by: Greg Kurz
Signed-off-by: Fabiano Rosas
---
arch/powerpc/kvm/book3s_hv_uvmem.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c
b/arch/powerpc/kvm/book3s_hv_uvmem.c
index 79b1202b1c62..9d26614b2a77 100644
--- a/arch/powerpc/kvm/book3s_hv_uvmem.c
+++ b/arch/powerpc/kvm/book3s_hv_uvmem.c
@@ -806,6 +806,9 @@ int kvmppc_uvmem_init(void)
void kvmppc_uvmem_free(void)
{
+ if (!kvmppc_uvmem_bitmap)
+ return;
+
memunmap_pages(_uvmem_pgmap);
release_mem_region(kvmppc_uvmem_pgmap.res.start,
resource_size(_uvmem_pgmap.res));
--
2.23.0
