diff mbox series

[SRU,Xenial,1/1] powerpc: signals: Discard transaction state from signal frames

Message ID e4646341de43b15a28459c09c5e6b67e5f229943.1526500931.git.joseph.salisbury@canonical.com
State New
Headers show
Series powerpc: signals: Discard transaction state from signal frames | expand

Commit Message

Joseph Salisbury May 18, 2018, 1:04 p.m. UTC 
From: Cyril Bur <cyrilbur@gmail.com>

BugLink: http://bugs.launchpad.net/bugs/1771439

Userspace can begin and suspend a transaction within the signal
handler which means they might enter sys_rt_sigreturn() with the
processor in suspended state.

sys_rt_sigreturn() wants to restore process context (which may have
been in a transaction before signal delivery). To do this it must
restore TM SPRS. To achieve this, any transaction initiated within the
signal frame must be discarded in order to be able to restore TM SPRs
as TM SPRs can only be manipulated non-transactionally..
>From the PowerPC ISA:
  TM Bad Thing Exception [Category: Transactional Memory]
   An attempt is made to execute a mtspr targeting a TM register in
   other than Non-transactional state.

Not doing so results in a TM Bad Thing:
[12045.221359] Kernel BUG at c000000000050a40 [verbose debug info unavailable]
[12045.221470] Unexpected TM Bad Thing exception at c000000000050a40 (msr 0x201033)
[12045.221540] Oops: Unrecoverable exception, sig: 6 [#1]
[12045.221586] SMP NR_CPUS=2048 NUMA PowerNV
[12045.221634] Modules linked in: xt_CHECKSUM iptable_mangle ipt_MASQUERADE
 nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4
 xt_conntrack nf_conntrack ipt_REJECT nf_reject_ipv4 xt_tcpudp bridge stp llc ebtable_filter
 ebtables ip6table_filter ip6_tables iptable_filter ip_tables x_tables kvm_hv kvm
 uio_pdrv_genirq ipmi_powernv uio powernv_rng ipmi_msghandler autofs4 ses enclosure
 scsi_transport_sas bnx2x ipr mdio libcrc32c
[12045.222167] CPU: 68 PID: 6178 Comm: sigreturnpanic Not tainted 4.7.0 #34
[12045.222224] task: c0000000fce38600 ti: c0000000fceb4000 task.ti: c0000000fceb4000
[12045.222293] NIP: c000000000050a40 LR: c0000000000163bc CTR: 0000000000000000
[12045.222361] REGS: c0000000fceb7ac0 TRAP: 0700   Not tainted (4.7.0)
[12045.222418] MSR: 9000000300201033 <SF,HV,ME,IR,DR,RI,LE,TM[SE]> CR: 28444280  XER: 20000000
[12045.222625] CFAR: c0000000000163b8 SOFTE: 0 PACATMSCRATCH: 900000014280f033
GPR00: 01100000b8000001 c0000000fceb7d40 c00000000139c100 c0000000fce390d0
GPR04: 900000034280f033 0000000000000000 0000000000000000 0000000000000000
GPR08: 0000000000000000 b000000000001033 0000000000000001 0000000000000000
GPR12: 0000000000000000 c000000002926400 0000000000000000 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR24: 0000000000000000 00003ffff98cadd0 00003ffff98cb470 0000000000000000
GPR28: 900000034280f033 c0000000fceb7ea0 0000000000000001 c0000000fce390d0
[12045.223535] NIP [c000000000050a40] tm_restore_sprs+0xc/0x1c
[12045.223584] LR [c0000000000163bc] tm_recheckpoint+0x5c/0xa0
[12045.223630] Call Trace:
[12045.223655] [c0000000fceb7d80] [c000000000026e74] sys_rt_sigreturn+0x494/0x6c0
[12045.223738] [c0000000fceb7e30] [c0000000000092e0] system_call+0x38/0x108
[12045.223806] Instruction dump:
[12045.223841] 7c800164 4e800020 7c0022a6 f80304a8 7c0222a6 f80304b0 7c0122a6 f80304b8
[12045.223955] 4e800020 e80304a8 7c0023a6 e80304b0 <7c0223a6> e80304b8 7c0123a6 4e800020
[12045.224074] ---[ end trace cb8002ee240bae76 ]---

It isn't clear exactly if there is really a use case for userspace
returning with a suspended transaction, however, doing so doesn't (on
its own) constitute a bad frame. As such, this patch simply discards
the transactional state of the context calling the sigreturn and
continues.

Reported-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Tested-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Reviewed-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Acked-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit 78a3e8889b4b6b99775ed954696ff3e017f5d19b)
Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>
---
 Documentation/powerpc/transactional_memory.txt |  2 ++
 arch/powerpc/kernel/signal_32.c                | 14 ++++++++++++++
 arch/powerpc/kernel/signal_64.c                | 14 ++++++++++++++
 3 files changed, 30 insertions(+)

Comments

Colin Ian King May 18, 2018, 3:30 p.m. UTC | #1 
On 18/05/18 14:04, Joseph Salisbury wrote:
> From: Cyril Bur <cyrilbur@gmail.com>
> 
> BugLink: http://bugs.launchpad.net/bugs/1771439
> 
> Userspace can begin and suspend a transaction within the signal
> handler which means they might enter sys_rt_sigreturn() with the
> processor in suspended state.
> 
> sys_rt_sigreturn() wants to restore process context (which may have
> been in a transaction before signal delivery). To do this it must
> restore TM SPRS. To achieve this, any transaction initiated within the
> signal frame must be discarded in order to be able to restore TM SPRs
> as TM SPRs can only be manipulated non-transactionally..
>>From the PowerPC ISA:
>   TM Bad Thing Exception [Category: Transactional Memory]
>    An attempt is made to execute a mtspr targeting a TM register in
>    other than Non-transactional state.
> 
> Not doing so results in a TM Bad Thing:
> [12045.221359] Kernel BUG at c000000000050a40 [verbose debug info unavailable]
> [12045.221470] Unexpected TM Bad Thing exception at c000000000050a40 (msr 0x201033)
> [12045.221540] Oops: Unrecoverable exception, sig: 6 [#1]
> [12045.221586] SMP NR_CPUS=2048 NUMA PowerNV
> [12045.221634] Modules linked in: xt_CHECKSUM iptable_mangle ipt_MASQUERADE
>  nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4
>  xt_conntrack nf_conntrack ipt_REJECT nf_reject_ipv4 xt_tcpudp bridge stp llc ebtable_filter
>  ebtables ip6table_filter ip6_tables iptable_filter ip_tables x_tables kvm_hv kvm
>  uio_pdrv_genirq ipmi_powernv uio powernv_rng ipmi_msghandler autofs4 ses enclosure
>  scsi_transport_sas bnx2x ipr mdio libcrc32c
> [12045.222167] CPU: 68 PID: 6178 Comm: sigreturnpanic Not tainted 4.7.0 #34
> [12045.222224] task: c0000000fce38600 ti: c0000000fceb4000 task.ti: c0000000fceb4000
> [12045.222293] NIP: c000000000050a40 LR: c0000000000163bc CTR: 0000000000000000
> [12045.222361] REGS: c0000000fceb7ac0 TRAP: 0700   Not tainted (4.7.0)
> [12045.222418] MSR: 9000000300201033 <SF,HV,ME,IR,DR,RI,LE,TM[SE]> CR: 28444280  XER: 20000000
> [12045.222625] CFAR: c0000000000163b8 SOFTE: 0 PACATMSCRATCH: 900000014280f033
> GPR00: 01100000b8000001 c0000000fceb7d40 c00000000139c100 c0000000fce390d0
> GPR04: 900000034280f033 0000000000000000 0000000000000000 0000000000000000
> GPR08: 0000000000000000 b000000000001033 0000000000000001 0000000000000000
> GPR12: 0000000000000000 c000000002926400 0000000000000000 0000000000000000
> GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> GPR24: 0000000000000000 00003ffff98cadd0 00003ffff98cb470 0000000000000000
> GPR28: 900000034280f033 c0000000fceb7ea0 0000000000000001 c0000000fce390d0
> [12045.223535] NIP [c000000000050a40] tm_restore_sprs+0xc/0x1c
> [12045.223584] LR [c0000000000163bc] tm_recheckpoint+0x5c/0xa0
> [12045.223630] Call Trace:
> [12045.223655] [c0000000fceb7d80] [c000000000026e74] sys_rt_sigreturn+0x494/0x6c0
> [12045.223738] [c0000000fceb7e30] [c0000000000092e0] system_call+0x38/0x108
> [12045.223806] Instruction dump:
> [12045.223841] 7c800164 4e800020 7c0022a6 f80304a8 7c0222a6 f80304b0 7c0122a6 f80304b8
> [12045.223955] 4e800020 e80304a8 7c0023a6 e80304b0 <7c0223a6> e80304b8 7c0123a6 4e800020
> [12045.224074] ---[ end trace cb8002ee240bae76 ]---
> 
> It isn't clear exactly if there is really a use case for userspace
> returning with a suspended transaction, however, doing so doesn't (on
> its own) constitute a bad frame. As such, this patch simply discards
> the transactional state of the context calling the sigreturn and
> continues.
> 
> Reported-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
> Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
> Tested-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
> Reviewed-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
> Acked-by: Simon Guo <wei.guo.simon@gmail.com>
> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> (cherry picked from commit 78a3e8889b4b6b99775ed954696ff3e017f5d19b)
> Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>
> ---
>  Documentation/powerpc/transactional_memory.txt |  2 ++
>  arch/powerpc/kernel/signal_32.c                | 14 ++++++++++++++
>  arch/powerpc/kernel/signal_64.c                | 14 ++++++++++++++
>  3 files changed, 30 insertions(+)
> 
> diff --git a/Documentation/powerpc/transactional_memory.txt b/Documentation/powerpc/transactional_memory.txt
> index ba0a2a4..e32fdbb 100644
> --- a/Documentation/powerpc/transactional_memory.txt
> +++ b/Documentation/powerpc/transactional_memory.txt
> @@ -167,6 +167,8 @@ signal will be rolled back anyway.
>  For signals taken in non-TM or suspended mode, we use the
>  normal/non-checkpointed stack pointer.
>  
> +Any transaction initiated inside a sighandler and suspended on return
> +from the sighandler to the kernel will get reclaimed and discarded.
>  
>  Failure cause codes used by kernel
>  ==================================
> diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
> index ef7c24e..cff1a4d 100644
> --- a/arch/powerpc/kernel/signal_32.c
> +++ b/arch/powerpc/kernel/signal_32.c
> @@ -1244,7 +1244,21 @@ long sys_rt_sigreturn(int r3, int r4, int r5, int r6, int r7, int r8,
>  		(regs->gpr[1] + __SIGNAL_FRAMESIZE + 16);
>  	if (!access_ok(VERIFY_READ, rt_sf, sizeof(*rt_sf)))
>  		goto bad;
> +
>  #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> +	/*
> +	 * If there is a transactional state then throw it away.
> +	 * The purpose of a sigreturn is to destroy all traces of the
> +	 * signal frame, this includes any transactional state created
> +	 * within in. We only check for suspended as we can never be
> +	 * active in the kernel, we are active, there is nothing better to
> +	 * do than go ahead and Bad Thing later.
> +	 * The cause is not important as there will never be a
> +	 * recheckpoint so it's not user visible.
> +	 */
> +	if (MSR_TM_SUSPENDED(mfmsr()))
> +		tm_reclaim_current(0);
> +
>  	if (__get_user(tmp, &rt_sf->uc.uc_link))
>  		goto bad;
>  	uc_transact = (struct ucontext __user *)(uintptr_t)tmp;
> diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
> index c676ece..1639b4a 100644
> --- a/arch/powerpc/kernel/signal_64.c
> +++ b/arch/powerpc/kernel/signal_64.c
> @@ -689,7 +689,21 @@ int sys_rt_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5,
>  	if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
>  		goto badframe;
>  	set_current_blocked(&set);
> +
>  #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> +	/*
> +	 * If there is a transactional state then throw it away.
> +	 * The purpose of a sigreturn is to destroy all traces of the
> +	 * signal frame, this includes any transactional state created
> +	 * within in. We only check for suspended as we can never be
> +	 * active in the kernel, we are active, there is nothing better to
> +	 * do than go ahead and Bad Thing later.
> +	 * The cause is not important as there will never be a
> +	 * recheckpoint so it's not user visible.
> +	 */
> +	if (MSR_TM_SUSPENDED(mfmsr()))
> +		tm_reclaim_current(0);
> +
>  	if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR]))
>  		goto badframe;
>  	if (MSR_TM_ACTIVE(msr)) {
> 
Clean upstream cherry pick, positive test results.

Acked-by: Colin Ian King <colin.king@canonical.com>
Kleber Sacilotto de Souza May 22, 2018, 2:33 p.m. UTC | #2 
On 05/18/18 15:04, Joseph Salisbury wrote:
> From: Cyril Bur <cyrilbur@gmail.com>
> 
> BugLink: http://bugs.launchpad.net/bugs/1771439
> 
> Userspace can begin and suspend a transaction within the signal
> handler which means they might enter sys_rt_sigreturn() with the
> processor in suspended state.
> 
> sys_rt_sigreturn() wants to restore process context (which may have
> been in a transaction before signal delivery). To do this it must
> restore TM SPRS. To achieve this, any transaction initiated within the
> signal frame must be discarded in order to be able to restore TM SPRs
> as TM SPRs can only be manipulated non-transactionally..
>>From the PowerPC ISA:
>   TM Bad Thing Exception [Category: Transactional Memory]
>    An attempt is made to execute a mtspr targeting a TM register in
>    other than Non-transactional state.
> 
> Not doing so results in a TM Bad Thing:
> [12045.221359] Kernel BUG at c000000000050a40 [verbose debug info unavailable]
> [12045.221470] Unexpected TM Bad Thing exception at c000000000050a40 (msr 0x201033)
> [12045.221540] Oops: Unrecoverable exception, sig: 6 [#1]
> [12045.221586] SMP NR_CPUS=2048 NUMA PowerNV
> [12045.221634] Modules linked in: xt_CHECKSUM iptable_mangle ipt_MASQUERADE
>  nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4
>  xt_conntrack nf_conntrack ipt_REJECT nf_reject_ipv4 xt_tcpudp bridge stp llc ebtable_filter
>  ebtables ip6table_filter ip6_tables iptable_filter ip_tables x_tables kvm_hv kvm
>  uio_pdrv_genirq ipmi_powernv uio powernv_rng ipmi_msghandler autofs4 ses enclosure
>  scsi_transport_sas bnx2x ipr mdio libcrc32c
> [12045.222167] CPU: 68 PID: 6178 Comm: sigreturnpanic Not tainted 4.7.0 #34
> [12045.222224] task: c0000000fce38600 ti: c0000000fceb4000 task.ti: c0000000fceb4000
> [12045.222293] NIP: c000000000050a40 LR: c0000000000163bc CTR: 0000000000000000
> [12045.222361] REGS: c0000000fceb7ac0 TRAP: 0700   Not tainted (4.7.0)
> [12045.222418] MSR: 9000000300201033 <SF,HV,ME,IR,DR,RI,LE,TM[SE]> CR: 28444280  XER: 20000000
> [12045.222625] CFAR: c0000000000163b8 SOFTE: 0 PACATMSCRATCH: 900000014280f033
> GPR00: 01100000b8000001 c0000000fceb7d40 c00000000139c100 c0000000fce390d0
> GPR04: 900000034280f033 0000000000000000 0000000000000000 0000000000000000
> GPR08: 0000000000000000 b000000000001033 0000000000000001 0000000000000000
> GPR12: 0000000000000000 c000000002926400 0000000000000000 0000000000000000
> GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> GPR24: 0000000000000000 00003ffff98cadd0 00003ffff98cb470 0000000000000000
> GPR28: 900000034280f033 c0000000fceb7ea0 0000000000000001 c0000000fce390d0
> [12045.223535] NIP [c000000000050a40] tm_restore_sprs+0xc/0x1c
> [12045.223584] LR [c0000000000163bc] tm_recheckpoint+0x5c/0xa0
> [12045.223630] Call Trace:
> [12045.223655] [c0000000fceb7d80] [c000000000026e74] sys_rt_sigreturn+0x494/0x6c0
> [12045.223738] [c0000000fceb7e30] [c0000000000092e0] system_call+0x38/0x108
> [12045.223806] Instruction dump:
> [12045.223841] 7c800164 4e800020 7c0022a6 f80304a8 7c0222a6 f80304b0 7c0122a6 f80304b8
> [12045.223955] 4e800020 e80304a8 7c0023a6 e80304b0 <7c0223a6> e80304b8 7c0123a6 4e800020
> [12045.224074] ---[ end trace cb8002ee240bae76 ]---
> 
> It isn't clear exactly if there is really a use case for userspace
> returning with a suspended transaction, however, doing so doesn't (on
> its own) constitute a bad frame. As such, this patch simply discards
> the transactional state of the context calling the sigreturn and
> continues.
> 
> Reported-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
> Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
> Tested-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
> Reviewed-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
> Acked-by: Simon Guo <wei.guo.simon@gmail.com>
> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> (cherry picked from commit 78a3e8889b4b6b99775ed954696ff3e017f5d19b)
> Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>
> ---
>  Documentation/powerpc/transactional_memory.txt |  2 ++
>  arch/powerpc/kernel/signal_32.c                | 14 ++++++++++++++
>  arch/powerpc/kernel/signal_64.c                | 14 ++++++++++++++
>  3 files changed, 30 insertions(+)
> 
> diff --git a/Documentation/powerpc/transactional_memory.txt b/Documentation/powerpc/transactional_memory.txt
> index ba0a2a4..e32fdbb 100644
> --- a/Documentation/powerpc/transactional_memory.txt
> +++ b/Documentation/powerpc/transactional_memory.txt
> @@ -167,6 +167,8 @@ signal will be rolled back anyway.
>  For signals taken in non-TM or suspended mode, we use the
>  normal/non-checkpointed stack pointer.
>  
> +Any transaction initiated inside a sighandler and suspended on return
> +from the sighandler to the kernel will get reclaimed and discarded.
>  
>  Failure cause codes used by kernel
>  ==================================
> diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
> index ef7c24e..cff1a4d 100644
> --- a/arch/powerpc/kernel/signal_32.c
> +++ b/arch/powerpc/kernel/signal_32.c
> @@ -1244,7 +1244,21 @@ long sys_rt_sigreturn(int r3, int r4, int r5, int r6, int r7, int r8,
>  		(regs->gpr[1] + __SIGNAL_FRAMESIZE + 16);
>  	if (!access_ok(VERIFY_READ, rt_sf, sizeof(*rt_sf)))
>  		goto bad;
> +
>  #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> +	/*
> +	 * If there is a transactional state then throw it away.
> +	 * The purpose of a sigreturn is to destroy all traces of the
> +	 * signal frame, this includes any transactional state created
> +	 * within in. We only check for suspended as we can never be
> +	 * active in the kernel, we are active, there is nothing better to
> +	 * do than go ahead and Bad Thing later.
> +	 * The cause is not important as there will never be a
> +	 * recheckpoint so it's not user visible.
> +	 */
> +	if (MSR_TM_SUSPENDED(mfmsr()))
> +		tm_reclaim_current(0);
> +
>  	if (__get_user(tmp, &rt_sf->uc.uc_link))
>  		goto bad;
>  	uc_transact = (struct ucontext __user *)(uintptr_t)tmp;
> diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
> index c676ece..1639b4a 100644
> --- a/arch/powerpc/kernel/signal_64.c
> +++ b/arch/powerpc/kernel/signal_64.c
> @@ -689,7 +689,21 @@ int sys_rt_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5,
>  	if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
>  		goto badframe;
>  	set_current_blocked(&set);
> +
>  #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> +	/*
> +	 * If there is a transactional state then throw it away.
> +	 * The purpose of a sigreturn is to destroy all traces of the
> +	 * signal frame, this includes any transactional state created
> +	 * within in. We only check for suspended as we can never be
> +	 * active in the kernel, we are active, there is nothing better to
> +	 * do than go ahead and Bad Thing later.
> +	 * The cause is not important as there will never be a
> +	 * recheckpoint so it's not user visible.
> +	 */
> +	if (MSR_TM_SUSPENDED(mfmsr()))
> +		tm_reclaim_current(0);
> +
>  	if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR]))
>  		goto badframe;
>  	if (MSR_TM_ACTIVE(msr)) {
> 

Scope limited to architecture and tested by the vendor.

Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
diff mbox series

Patch

diff --git a/Documentation/powerpc/transactional_memory.txt b/Documentation/powerpc/transactional_memory.txt
index ba0a2a4..e32fdbb 100644
--- a/Documentation/powerpc/transactional_memory.txt
+++ b/Documentation/powerpc/transactional_memory.txt
@@ -167,6 +167,8 @@  signal will be rolled back anyway.
 For signals taken in non-TM or suspended mode, we use the
 normal/non-checkpointed stack pointer.
 
+Any transaction initiated inside a sighandler and suspended on return
+from the sighandler to the kernel will get reclaimed and discarded.
 
 Failure cause codes used by kernel
 ==================================
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index ef7c24e..cff1a4d 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -1244,7 +1244,21 @@  long sys_rt_sigreturn(int r3, int r4, int r5, int r6, int r7, int r8,
 		(regs->gpr[1] + __SIGNAL_FRAMESIZE + 16);
 	if (!access_ok(VERIFY_READ, rt_sf, sizeof(*rt_sf)))
 		goto bad;
+
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+	/*
+	 * If there is a transactional state then throw it away.
+	 * The purpose of a sigreturn is to destroy all traces of the
+	 * signal frame, this includes any transactional state created
+	 * within in. We only check for suspended as we can never be
+	 * active in the kernel, we are active, there is nothing better to
+	 * do than go ahead and Bad Thing later.
+	 * The cause is not important as there will never be a
+	 * recheckpoint so it's not user visible.
+	 */
+	if (MSR_TM_SUSPENDED(mfmsr()))
+		tm_reclaim_current(0);
+
 	if (__get_user(tmp, &rt_sf->uc.uc_link))
 		goto bad;
 	uc_transact = (struct ucontext __user *)(uintptr_t)tmp;
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index c676ece..1639b4a 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -689,7 +689,21 @@  int sys_rt_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5,
 	if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
 		goto badframe;
 	set_current_blocked(&set);
+
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+	/*
+	 * If there is a transactional state then throw it away.
+	 * The purpose of a sigreturn is to destroy all traces of the
+	 * signal frame, this includes any transactional state created
+	 * within in. We only check for suspended as we can never be
+	 * active in the kernel, we are active, there is nothing better to
+	 * do than go ahead and Bad Thing later.
+	 * The cause is not important as there will never be a
+	 * recheckpoint so it's not user visible.
+	 */
+	if (MSR_TM_SUSPENDED(mfmsr()))
+		tm_reclaim_current(0);
+
 	if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR]))
 		goto badframe;
 	if (MSR_TM_ACTIVE(msr)) {