* [PATCH] arm64: fix infinite stacktrace
@ 2018-06-14 18:58 Mikulas Patocka
2018-06-15 11:58 ` Mark Rutland
0 siblings, 1 reply; 8+ messages in thread
From: Mikulas Patocka @ 2018-06-14 18:58 UTC (permalink / raw)
To: linux-arm-kernel
I've got this infinite stacktrace when debugging another problem:
[ 908.795225] INFO: rcu_preempt detected stalls on CPUs/tasks:
[ 908.796176] 1-...!: (1 GPs behind) idle=952/1/4611686018427387904 softirq=1462/1462 fqs=355
[ 908.797692] 2-...!: (1 GPs behind) idle=f42/1/4611686018427387904 softirq=1550/1551 fqs=355
[ 908.799189] (detected by 0, t=2109 jiffies, g=130, c=129, q=235)
[ 908.800284] Task dump for CPU 1:
[ 908.800871] kworker/1:1 R running task 0 32 2 0x00000022
[ 908.802127] Workqueue: writecache-writeabck writecache_writeback [dm_writecache]
[ 908.820285] Call trace:
[ 908.824785] __switch_to+0x68/0x90
[ 908.837661] 0xfffffe00603afd90
[ 908.844119] 0xfffffe00603afd90
[ 908.850091] 0xfffffe00603afd90
[ 908.854285] 0xfffffe00603afd90
[ 908.863538] 0xfffffe00603afd90
[ 908.865523] 0xfffffe00603afd90
The machine just locked up and kept on printing the same line over and
over again. This patch fixes it.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable at vger.kernel.org
Index: linux-2.6/arch/arm64/kernel/stacktrace.c
===================================================================
--- linux-2.6.orig/arch/arm64/kernel/stacktrace.c
+++ linux-2.6/arch/arm64/kernel/stacktrace.c
@@ -56,6 +56,9 @@ int notrace unwind_frame(struct task_str
frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp));
frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8));
+ if (frame->fp <= fp)
+ return -EINVAL;
+
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
if (tsk->ret_stack &&
(frame->pc == (unsigned long)return_to_handler)) {
^ permalink raw reply [flat|nested] 8+ messages in thread* [PATCH] arm64: fix infinite stacktrace 2018-06-14 18:58 [PATCH] arm64: fix infinite stacktrace Mikulas Patocka @ 2018-06-15 11:58 ` Mark Rutland 2018-06-27 16:41 ` Will Deacon 0 siblings, 1 reply; 8+ messages in thread From: Mark Rutland @ 2018-06-15 11:58 UTC (permalink / raw) To: linux-arm-kernel Hi, On Thu, Jun 14, 2018 at 02:58:21PM -0400, Mikulas Patocka wrote: > I've got this infinite stacktrace when debugging another problem: > [ 908.795225] INFO: rcu_preempt detected stalls on CPUs/tasks: > [ 908.796176] 1-...!: (1 GPs behind) idle=952/1/4611686018427387904 softirq=1462/1462 fqs=355 > [ 908.797692] 2-...!: (1 GPs behind) idle=f42/1/4611686018427387904 softirq=1550/1551 fqs=355 > [ 908.799189] (detected by 0, t=2109 jiffies, g=130, c=129, q=235) > [ 908.800284] Task dump for CPU 1: > [ 908.800871] kworker/1:1 R running task 0 32 2 0x00000022 > [ 908.802127] Workqueue: writecache-writeabck writecache_writeback [dm_writecache] > [ 908.820285] Call trace: > [ 908.824785] __switch_to+0x68/0x90 > [ 908.837661] 0xfffffe00603afd90 > [ 908.844119] 0xfffffe00603afd90 > [ 908.850091] 0xfffffe00603afd90 > [ 908.854285] 0xfffffe00603afd90 > [ 908.863538] 0xfffffe00603afd90 > [ 908.865523] 0xfffffe00603afd90 > > The machine just locked up and kept on printing the same line over and > over again. This patch fixes it. > > Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> > Cc: stable at vger.kernel.org Given this can only occur when there's a corrupted stack (where a frame record points to itself), I'm not sure this requires a cc stable. > Index: linux-2.6/arch/arm64/kernel/stacktrace.c > =================================================================== > --- linux-2.6.orig/arch/arm64/kernel/stacktrace.c > +++ linux-2.6/arch/arm64/kernel/stacktrace.c > @@ -56,6 +56,9 @@ int notrace unwind_frame(struct task_str > frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp)); > frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8)); > > + if (frame->fp <= fp) > + return -EINVAL; > + Dave Martin had a series [1] which addressed this along with a number of other cases where stack traces might not terminate. Dave, do you plan to respin that? Thanks, Mark. [1] https://lkml.kernel.org/r/1524503223-17576-1-git-send-email-Dave.Martin at arm.com ^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH] arm64: fix infinite stacktrace 2018-06-15 11:58 ` Mark Rutland @ 2018-06-27 16:41 ` Will Deacon 2018-06-28 16:49 ` Dave Martin 0 siblings, 1 reply; 8+ messages in thread From: Will Deacon @ 2018-06-27 16:41 UTC (permalink / raw) To: linux-arm-kernel Hi all, On Fri, Jun 15, 2018 at 12:58:23PM +0100, Mark Rutland wrote: > On Thu, Jun 14, 2018 at 02:58:21PM -0400, Mikulas Patocka wrote: > > I've got this infinite stacktrace when debugging another problem: > > [ 908.795225] INFO: rcu_preempt detected stalls on CPUs/tasks: > > [ 908.796176] 1-...!: (1 GPs behind) idle=952/1/4611686018427387904 softirq=1462/1462 fqs=355 > > [ 908.797692] 2-...!: (1 GPs behind) idle=f42/1/4611686018427387904 softirq=1550/1551 fqs=355 > > [ 908.799189] (detected by 0, t=2109 jiffies, g=130, c=129, q=235) > > [ 908.800284] Task dump for CPU 1: > > [ 908.800871] kworker/1:1 R running task 0 32 2 0x00000022 > > [ 908.802127] Workqueue: writecache-writeabck writecache_writeback [dm_writecache] > > [ 908.820285] Call trace: > > [ 908.824785] __switch_to+0x68/0x90 > > [ 908.837661] 0xfffffe00603afd90 > > [ 908.844119] 0xfffffe00603afd90 > > [ 908.850091] 0xfffffe00603afd90 > > [ 908.854285] 0xfffffe00603afd90 > > [ 908.863538] 0xfffffe00603afd90 > > [ 908.865523] 0xfffffe00603afd90 > > > > The machine just locked up and kept on printing the same line over and > > over again. This patch fixes it. > > > > Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> > > Cc: stable at vger.kernel.org > > Given this can only occur when there's a corrupted stack (where a frame > record points to itself), I'm not sure this requires a cc stable. > > > Index: linux-2.6/arch/arm64/kernel/stacktrace.c > > =================================================================== > > --- linux-2.6.orig/arch/arm64/kernel/stacktrace.c > > +++ linux-2.6/arch/arm64/kernel/stacktrace.c > > @@ -56,6 +56,9 @@ int notrace unwind_frame(struct task_str > > frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp)); > > frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8)); > > > > + if (frame->fp <= fp) > > + return -EINVAL; > > + > > Dave Martin had a series [1] which addressed this along with a number of > other cases where stack traces might not terminate. > > Dave, do you plan to respin that? I'd be interested in an update on that; we clearly should be fixing this in one way or another. Mikulus -- would you be able to test and/or review it, please? Will ^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH] arm64: fix infinite stacktrace 2018-06-27 16:41 ` Will Deacon @ 2018-06-28 16:49 ` Dave Martin 2018-07-10 3:04 ` Mikulas Patocka 0 siblings, 1 reply; 8+ messages in thread From: Dave Martin @ 2018-06-28 16:49 UTC (permalink / raw) To: linux-arm-kernel On Wed, Jun 27, 2018 at 05:41:51PM +0100, Will Deacon wrote: > Hi all, > > On Fri, Jun 15, 2018 at 12:58:23PM +0100, Mark Rutland wrote: > > On Thu, Jun 14, 2018 at 02:58:21PM -0400, Mikulas Patocka wrote: > > > I've got this infinite stacktrace when debugging another problem: > > > [ 908.795225] INFO: rcu_preempt detected stalls on CPUs/tasks: > > > [ 908.796176] 1-...!: (1 GPs behind) idle=952/1/4611686018427387904 softirq=1462/1462 fqs=355 > > > [ 908.797692] 2-...!: (1 GPs behind) idle=f42/1/4611686018427387904 softirq=1550/1551 fqs=355 > > > [ 908.799189] (detected by 0, t=2109 jiffies, g=130, c=129, q=235) > > > [ 908.800284] Task dump for CPU 1: > > > [ 908.800871] kworker/1:1 R running task 0 32 2 0x00000022 > > > [ 908.802127] Workqueue: writecache-writeabck writecache_writeback [dm_writecache] > > > [ 908.820285] Call trace: > > > [ 908.824785] __switch_to+0x68/0x90 > > > [ 908.837661] 0xfffffe00603afd90 > > > [ 908.844119] 0xfffffe00603afd90 > > > [ 908.850091] 0xfffffe00603afd90 > > > [ 908.854285] 0xfffffe00603afd90 > > > [ 908.863538] 0xfffffe00603afd90 > > > [ 908.865523] 0xfffffe00603afd90 > > > > > > The machine just locked up and kept on printing the same line over and > > > over again. This patch fixes it. > > > > > > Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> > > > Cc: stable at vger.kernel.org > > > > Given this can only occur when there's a corrupted stack (where a frame > > record points to itself), I'm not sure this requires a cc stable. > > > > > Index: linux-2.6/arch/arm64/kernel/stacktrace.c > > > =================================================================== > > > --- linux-2.6.orig/arch/arm64/kernel/stacktrace.c > > > +++ linux-2.6/arch/arm64/kernel/stacktrace.c > > > @@ -56,6 +56,9 @@ int notrace unwind_frame(struct task_str > > > frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp)); > > > frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8)); > > > > > > + if (frame->fp <= fp) > > > + return -EINVAL; > > > + > > > > Dave Martin had a series [1] which addressed this along with a number of > > other cases where stack traces might not terminate. > > > > Dave, do you plan to respin that? > > I'd be interested in an update on that; we clearly should be fixing this in > one way or another. > > Mikulus -- would you be able to test and/or review it, please? My patch was arguably over-engineered, and broken in some way connected with SDEI. Unfortunately I've had too much other stuff to do... I could take another look, but it may take time to get to it. Alternatively, if someone wants to pick up my patch and take it forward, I'm happy to comment. Cheers ---Dave ^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH] arm64: fix infinite stacktrace 2018-06-28 16:49 ` Dave Martin @ 2018-07-10 3:04 ` Mikulas Patocka 2018-07-10 9:13 ` Will Deacon 0 siblings, 1 reply; 8+ messages in thread From: Mikulas Patocka @ 2018-07-10 3:04 UTC (permalink / raw) To: linux-arm-kernel On Thu, 28 Jun 2018, Dave Martin wrote: > On Wed, Jun 27, 2018 at 05:41:51PM +0100, Will Deacon wrote: > > Hi all, > > > > On Fri, Jun 15, 2018 at 12:58:23PM +0100, Mark Rutland wrote: > > > On Thu, Jun 14, 2018 at 02:58:21PM -0400, Mikulas Patocka wrote: > > > > I've got this infinite stacktrace when debugging another problem: > > > > [ 908.795225] INFO: rcu_preempt detected stalls on CPUs/tasks: > > > > [ 908.796176] 1-...!: (1 GPs behind) idle=952/1/4611686018427387904 softirq=1462/1462 fqs=355 > > > > [ 908.797692] 2-...!: (1 GPs behind) idle=f42/1/4611686018427387904 softirq=1550/1551 fqs=355 > > > > [ 908.799189] (detected by 0, t=2109 jiffies, g=130, c=129, q=235) > > > > [ 908.800284] Task dump for CPU 1: > > > > [ 908.800871] kworker/1:1 R running task 0 32 2 0x00000022 > > > > [ 908.802127] Workqueue: writecache-writeabck writecache_writeback [dm_writecache] > > > > [ 908.820285] Call trace: > > > > [ 908.824785] __switch_to+0x68/0x90 > > > > [ 908.837661] 0xfffffe00603afd90 > > > > [ 908.844119] 0xfffffe00603afd90 > > > > [ 908.850091] 0xfffffe00603afd90 > > > > [ 908.854285] 0xfffffe00603afd90 > > > > [ 908.863538] 0xfffffe00603afd90 > > > > [ 908.865523] 0xfffffe00603afd90 > > > > > > > > The machine just locked up and kept on printing the same line over and > > > > over again. This patch fixes it. > > > > > > > > Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> > > > > Cc: stable at vger.kernel.org > > > > > > Given this can only occur when there's a corrupted stack (where a frame > > > record points to itself), I'm not sure this requires a cc stable. > > > > > > > Index: linux-2.6/arch/arm64/kernel/stacktrace.c > > > > =================================================================== > > > > --- linux-2.6.orig/arch/arm64/kernel/stacktrace.c > > > > +++ linux-2.6/arch/arm64/kernel/stacktrace.c > > > > @@ -56,6 +56,9 @@ int notrace unwind_frame(struct task_str > > > > frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp)); > > > > frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8)); > > > > > > > > + if (frame->fp <= fp) > > > > + return -EINVAL; > > > > + > > > > > > Dave Martin had a series [1] which addressed this along with a number of > > > other cases where stack traces might not terminate. > > > > > > Dave, do you plan to respin that? > > > > I'd be interested in an update on that; we clearly should be fixing this in > > one way or another. > > > > Mikulus -- would you be able to test and/or review it, please? > > My patch was arguably over-engineered, and broken in some way connected > with SDEI. Unfortunately I've had too much other stuff to do... > > I could take another look, but it may take time to get to it. > > Alternatively, if someone wants to pick up my patch and take it forward, > I'm happy to comment. > > Cheers > ---Dave Or - what about this patch? It doesn't guarantee that infinite loop won't happen, but it at least catches the most obvious loop on the same address. From: Mikulas Patocka <mpatocka@redhat.com> Subject: [PATCH] arm64: fix infinite stacktrace I've got this infinite stacktrace when debugging another problem: [ 908.795225] INFO: rcu_preempt detected stalls on CPUs/tasks: [ 908.796176] 1-...!: (1 GPs behind) idle=952/1/4611686018427387904 softirq=1462/1462 fqs=355 [ 908.797692] 2-...!: (1 GPs behind) idle=f42/1/4611686018427387904 softirq=1550/1551 fqs=355 [ 908.799189] (detected by 0, t=2109 jiffies, g=130, c=129, q=235) [ 908.800284] Task dump for CPU 1: [ 908.800871] kworker/1:1 R running task 0 32 2 0x00000022 [ 908.802127] Workqueue: writecache-writeabck writecache_writeback [dm_writecache] [ 908.820285] Call trace: [ 908.824785] __switch_to+0x68/0x90 [ 908.837661] 0xfffffe00603afd90 [ 908.844119] 0xfffffe00603afd90 [ 908.850091] 0xfffffe00603afd90 [ 908.854285] 0xfffffe00603afd90 [ 908.863538] 0xfffffe00603afd90 [ 908.865523] 0xfffffe00603afd90 The machine just locked up and kept on printing the same line over and over again. This patch fixes it. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable at vger.kernel.org --- arch/arm64/kernel/stacktrace.c | 3 +++ 1 file changed, 3 insertions(+) Index: linux-2.6/arch/arm64/kernel/stacktrace.c =================================================================== --- linux-2.6.orig/arch/arm64/kernel/stacktrace.c 2018-07-10 05:01:56.990000000 +0200 +++ linux-2.6/arch/arm64/kernel/stacktrace.c 2018-07-10 05:02:51.650000000 +0200 @@ -56,6 +56,9 @@ int notrace unwind_frame(struct task_str frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp)); frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8)); + if (frame->fp == fp) + return -EINVAL; + #ifdef CONFIG_FUNCTION_GRAPH_TRACER if (tsk->ret_stack && (frame->pc == (unsigned long)return_to_handler)) { ^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH] arm64: fix infinite stacktrace 2018-07-10 3:04 ` Mikulas Patocka @ 2018-07-10 9:13 ` Will Deacon 2018-07-10 18:10 ` Mikulas Patocka 0 siblings, 1 reply; 8+ messages in thread From: Will Deacon @ 2018-07-10 9:13 UTC (permalink / raw) To: linux-arm-kernel On Mon, Jul 09, 2018 at 11:04:33PM -0400, Mikulas Patocka wrote: > On Thu, 28 Jun 2018, Dave Martin wrote: > > Alternatively, if someone wants to pick up my patch and take it forward, > > I'm happy to comment. > > > > Cheers > > ---Dave > > Or - what about this patch? It doesn't guarantee that infinite loop won't > happen, but it at least catches the most obvious loop on the same address. > > > From: Mikulas Patocka <mpatocka@redhat.com> > Subject: [PATCH] arm64: fix infinite stacktrace > > I've got this infinite stacktrace when debugging another problem: > [ 908.795225] INFO: rcu_preempt detected stalls on CPUs/tasks: > [ 908.796176] 1-...!: (1 GPs behind) idle=952/1/4611686018427387904 softirq=1462/1462 fqs=355 > [ 908.797692] 2-...!: (1 GPs behind) idle=f42/1/4611686018427387904 softirq=1550/1551 fqs=355 > [ 908.799189] (detected by 0, t=2109 jiffies, g=130, c=129, q=235) > [ 908.800284] Task dump for CPU 1: > [ 908.800871] kworker/1:1 R running task 0 32 2 0x00000022 > [ 908.802127] Workqueue: writecache-writeabck writecache_writeback [dm_writecache] > [ 908.820285] Call trace: > [ 908.824785] __switch_to+0x68/0x90 > [ 908.837661] 0xfffffe00603afd90 > [ 908.844119] 0xfffffe00603afd90 > [ 908.850091] 0xfffffe00603afd90 > [ 908.854285] 0xfffffe00603afd90 > [ 908.863538] 0xfffffe00603afd90 > [ 908.865523] 0xfffffe00603afd90 > > The machine just locked up and kept on printing the same line over and > over again. This patch fixes it. > > Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> > Cc: stable at vger.kernel.org > > --- > arch/arm64/kernel/stacktrace.c | 3 +++ > 1 file changed, 3 insertions(+) > > Index: linux-2.6/arch/arm64/kernel/stacktrace.c > =================================================================== > --- linux-2.6.orig/arch/arm64/kernel/stacktrace.c 2018-07-10 05:01:56.990000000 +0200 > +++ linux-2.6/arch/arm64/kernel/stacktrace.c 2018-07-10 05:02:51.650000000 +0200 > @@ -56,6 +56,9 @@ int notrace unwind_frame(struct task_str > frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp)); > frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8)); > > + if (frame->fp == fp) > + return -EINVAL; I've already queued your previous patch using '<=' (it's in -next). If you want to change it, please send patches on top of the arm64 for-next/core branch. Will ^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH] arm64: fix infinite stacktrace 2018-07-10 9:13 ` Will Deacon @ 2018-07-10 18:10 ` Mikulas Patocka 2018-07-12 10:39 ` Will Deacon 0 siblings, 1 reply; 8+ messages in thread From: Mikulas Patocka @ 2018-07-10 18:10 UTC (permalink / raw) To: linux-arm-kernel On Tue, 10 Jul 2018, Will Deacon wrote: > On Mon, Jul 09, 2018 at 11:04:33PM -0400, Mikulas Patocka wrote: > > On Thu, 28 Jun 2018, Dave Martin wrote: > > > Alternatively, if someone wants to pick up my patch and take it forward, > > > I'm happy to comment. > > > > > > Cheers > > > ---Dave > > > > Or - what about this patch? It doesn't guarantee that infinite loop won't > > happen, but it at least catches the most obvious loop on the same address. > > > > > > From: Mikulas Patocka <mpatocka@redhat.com> > > Subject: [PATCH] arm64: fix infinite stacktrace > > > > I've got this infinite stacktrace when debugging another problem: > > [ 908.795225] INFO: rcu_preempt detected stalls on CPUs/tasks: > > [ 908.796176] 1-...!: (1 GPs behind) idle=952/1/4611686018427387904 softirq=1462/1462 fqs=355 > > [ 908.797692] 2-...!: (1 GPs behind) idle=f42/1/4611686018427387904 softirq=1550/1551 fqs=355 > > [ 908.799189] (detected by 0, t=2109 jiffies, g=130, c=129, q=235) > > [ 908.800284] Task dump for CPU 1: > > [ 908.800871] kworker/1:1 R running task 0 32 2 0x00000022 > > [ 908.802127] Workqueue: writecache-writeabck writecache_writeback [dm_writecache] > > [ 908.820285] Call trace: > > [ 908.824785] __switch_to+0x68/0x90 > > [ 908.837661] 0xfffffe00603afd90 > > [ 908.844119] 0xfffffe00603afd90 > > [ 908.850091] 0xfffffe00603afd90 > > [ 908.854285] 0xfffffe00603afd90 > > [ 908.863538] 0xfffffe00603afd90 > > [ 908.865523] 0xfffffe00603afd90 > > > > The machine just locked up and kept on printing the same line over and > > over again. This patch fixes it. > > > > Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> > > Cc: stable at vger.kernel.org > > > > --- > > arch/arm64/kernel/stacktrace.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > Index: linux-2.6/arch/arm64/kernel/stacktrace.c > > =================================================================== > > --- linux-2.6.orig/arch/arm64/kernel/stacktrace.c 2018-07-10 05:01:56.990000000 +0200 > > +++ linux-2.6/arch/arm64/kernel/stacktrace.c 2018-07-10 05:02:51.650000000 +0200 > > @@ -56,6 +56,9 @@ int notrace unwind_frame(struct task_str > > frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp)); > > frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8)); > > > > + if (frame->fp == fp) > > + return -EINVAL; > > I've already queued your previous patch using '<=' (it's in -next). If you > want to change it, please send patches on top of the arm64 for-next/core > branch. > > Will I don't know - is this function supposed to backtrace against more discontiguous stacks? If yes, then the patch with (frame->fp <= fp) is incorrect. If no, then the condition (frame->fp <= fp) could be there. Mikulas ^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH] arm64: fix infinite stacktrace 2018-07-10 18:10 ` Mikulas Patocka @ 2018-07-12 10:39 ` Will Deacon 0 siblings, 0 replies; 8+ messages in thread From: Will Deacon @ 2018-07-12 10:39 UTC (permalink / raw) To: linux-arm-kernel On Tue, Jul 10, 2018 at 02:10:04PM -0400, Mikulas Patocka wrote: > On Tue, 10 Jul 2018, Will Deacon wrote: > > On Mon, Jul 09, 2018 at 11:04:33PM -0400, Mikulas Patocka wrote: > > > Index: linux-2.6/arch/arm64/kernel/stacktrace.c > > > =================================================================== > > > --- linux-2.6.orig/arch/arm64/kernel/stacktrace.c 2018-07-10 05:01:56.990000000 +0200 > > > +++ linux-2.6/arch/arm64/kernel/stacktrace.c 2018-07-10 05:02:51.650000000 +0200 > > > @@ -56,6 +56,9 @@ int notrace unwind_frame(struct task_str > > > frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp)); > > > frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8)); > > > > > > + if (frame->fp == fp) > > > + return -EINVAL; > > > > I've already queued your previous patch using '<=' (it's in -next). If you > > want to change it, please send patches on top of the arm64 for-next/core > > branch. > > > > Will > > I don't know - is this function supposed to backtrace against more > discontiguous stacks? If yes, then the patch with (frame->fp <= fp) is > incorrect. If no, then the condition (frame->fp <= fp) could be there. Ah yes, your original patch breaks with irqstacks, so I'll need to revert it. Using '==' feels like a big hack to me. Will ^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2018-07-12 10:39 UTC | newest] Thread overview: 8+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2018-06-14 18:58 [PATCH] arm64: fix infinite stacktrace Mikulas Patocka 2018-06-15 11:58 ` Mark Rutland 2018-06-27 16:41 ` Will Deacon 2018-06-28 16:49 ` Dave Martin 2018-07-10 3:04 ` Mikulas Patocka 2018-07-10 9:13 ` Will Deacon 2018-07-10 18:10 ` Mikulas Patocka 2018-07-12 10:39 ` Will Deacon
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).