[PATCH] tracing/net_sched: NULL pointer dereference in perf_trace_qdisc_reset()

[PATCH] tracing/net_sched: NULL pointer dereference in perf_trace_qdisc_reset()

[Yunseong Kim]

Support backports for stable version. There are two places where null
deref could happen before
commit 2c92ca849fcc ("tracing/treewide: Remove second parameter of __assign_str()")
Link: https://lore.kernel.org/linux-trace-kernel/20240516133454.681ba6a0@rorschach.local.home/

I've checked +v6.1.82 +v6.6.22 +v6.7.10, +v6.8, +6.9, this version need
to be applied, So, I applied the patch, tested it again, and confirmed
working fine.

Fixes: 51270d573a8d ("tracing/net_sched: Fix tracepoints that save qdisc_dev() as a string")
Link: https://lore.kernel.org/lkml/20240229143432.273b4871@gandalf.local.home/t/
Cc: netdev@vger.kernel.org
Cc: stable@vger.kernel.org # +v6.1.82 +v6.6.22 +v6.7.10, +v6.8, +6.9
Tested-by: Yunseong Kim <yskelg@gmail.com>
Reviewed-by: Pedro Tammela <pctammela@mojatatu.com>
Signed-off-by: Yunseong Kim <yskelg@gmail.com>
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Link: https://lore.kernel.org/r/20240624173320.24945-4-yskelg@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/trace/events/qdisc.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/trace/events/qdisc.h b/include/trace/events/qdisc.h
index 1f4258308b96..061fd4960303 100644
--- a/include/trace/events/qdisc.h
+++ b/include/trace/events/qdisc.h
@@ -81,14 +81,14 @@ TRACE_EVENT(qdisc_reset,
 	TP_ARGS(q),
 
 	TP_STRUCT__entry(
-		__string(	dev,		qdisc_dev(q)->name	)
+		__string(	dev,		qdisc_dev(q) ? qdisc_dev(q)->name : "(null)"	)
 		__string(	kind,		q->ops->id		)
 		__field(	u32,		parent			)
 		__field(	u32,		handle			)
 	),
 
 	TP_fast_assign(
-		__assign_str(dev, qdisc_dev(q)->name);
+		__assign_str(dev, qdisc_dev(q) ? qdisc_dev(q)->name : "(null)");
 		__assign_str(kind, q->ops->id);
 		__entry->parent = q->parent;
 		__entry->handle = q->handle;
-- 
2.45.2

Re: [PATCH] tracing/net_sched: NULL pointer dereference in perf_trace_qdisc_reset()

[Jakub Kicinski]

On Wed,  3 Jul 2024 03:01:47 +0900 Yunseong Kim wrote:
> Support backports for stable version. There are two places where null
> deref could happen before
> commit 2c92ca849fcc ("tracing/treewide: Remove second parameter of __assign_str()")
> Link: https://lore.kernel.org/linux-trace-kernel/20240516133454.681ba6a0@rorschach.local.home/
> 
> I've checked +v6.1.82 +v6.6.22 +v6.7.10, +v6.8, +6.9, this version need
> to be applied, So, I applied the patch, tested it again, and confirmed
> working fine.

You're missing the customary "[ Upstream commit <upstream commit> ]"
line, not sure Greg will pick this up.

Re: [PATCH] tracing/net_sched: NULL pointer dereference in perf_trace_qdisc_reset()

[Greg Kroah-Hartman]

On Wed, Jul 03, 2024 at 07:18:35PM -0700, Jakub Kicinski wrote:
> On Wed,  3 Jul 2024 03:01:47 +0900 Yunseong Kim wrote:
> > Support backports for stable version. There are two places where null
> > deref could happen before
> > commit 2c92ca849fcc ("tracing/treewide: Remove second parameter of __assign_str()")
> > Link: https://lore.kernel.org/linux-trace-kernel/20240516133454.681ba6a0@rorschach.local.home/
> > 
> > I've checked +v6.1.82 +v6.6.22 +v6.7.10, +v6.8, +6.9, this version need
> > to be applied, So, I applied the patch, tested it again, and confirmed
> > working fine.
> 
> You're missing the customary "[ Upstream commit <upstream commit> ]"
> line, not sure Greg will pick this up.
> 

Yeah, I missed this, needs to be very obvious what is happening here.
I'll replace the version in the queues with this one now, thanks.

greg k-h

Re: [PATCH] tracing/net_sched: NULL pointer dereference in perf_trace_qdisc_reset()

[Yunseong Kim]

Hi Greg, Hi Jakub

On 7/4/24 6:32 오후, Greg Kroah-Hartman wrote:
> On Wed, Jul 03, 2024 at 07:18:35PM -0700, Jakub Kicinski wrote:
>> On Wed,  3 Jul 2024 03:01:47 +0900 Yunseong Kim wrote:
>>> Support backports for stable version. There are two places where null
>>> deref could happen before
>>> commit 2c92ca849fcc ("tracing/treewide: Remove second parameter of __assign_str()")
>>> Link: https://lore.kernel.org/linux-trace-kernel/20240516133454.681ba6a0@rorschach.local.home/
>>>
>>> I've checked +v6.1.82 +v6.6.22 +v6.7.10, +v6.8, +6.9, this version need
>>> to be applied, So, I applied the patch, tested it again, and confirmed
>>> working fine.
>>
>> You're missing the customary "[ Upstream commit <upstream commit> ]"
>> line, not sure Greg will pick this up.
>>
> 
> Yeah, I missed this, needs to be very obvious what is happening here.
> I'll replace the version in the queues with this one now, thanks.
> 
> greg k-h


Thank you for your hard work.


This fix need to be applied versions in +v5.10.213, +v5.15.152, +v6.1.82
+v6.6.22, +v6.7.10, +v6.8, +6.9


Warm regards,

Yunseong Kim

Re: [PATCH] tracing/net_sched: NULL pointer dereference in perf_trace_qdisc_reset()

[Greg Kroah-Hartman]

On Thu, Jul 04, 2024 at 08:16:34PM +0900, Yunseong Kim wrote:
> Hi Greg, Hi Jakub
> 
> On 7/4/24 6:32 오후, Greg Kroah-Hartman wrote:
> > On Wed, Jul 03, 2024 at 07:18:35PM -0700, Jakub Kicinski wrote:
> >> On Wed,  3 Jul 2024 03:01:47 +0900 Yunseong Kim wrote:
> >>> Support backports for stable version. There are two places where null
> >>> deref could happen before
> >>> commit 2c92ca849fcc ("tracing/treewide: Remove second parameter of __assign_str()")
> >>> Link: https://lore.kernel.org/linux-trace-kernel/20240516133454.681ba6a0@rorschach.local.home/
> >>>
> >>> I've checked +v6.1.82 +v6.6.22 +v6.7.10, +v6.8, +6.9, this version need
> >>> to be applied, So, I applied the patch, tested it again, and confirmed
> >>> working fine.
> >>
> >> You're missing the customary "[ Upstream commit <upstream commit> ]"
> >> line, not sure Greg will pick this up.
> >>
> > 
> > Yeah, I missed this, needs to be very obvious what is happening here.
> > I'll replace the version in the queues with this one now, thanks.
> > 
> > greg k-h
> 
> 
> Thank you for your hard work.
> 
> 
> This fix need to be applied versions in +v5.10.213, +v5.15.152, +v6.1.82
> +v6.6.22, +v6.7.10, +v6.8, +6.9
> 

Already done.