From: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
Mathieu Poirier <mathieu.poirier@linaro.org>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
linux-arm-msm@vger.kernel.org, coresight@lists.linaro.org,
linux-kernel@vger.kernel.org,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Stephen Boyd <swboyd@chromium.org>,
Ingo Molnar <mingo@redhat.com>,
Namhyung Kim <namhyung@kernel.org>, Jiri Olsa <jolsa@redhat.com>,
linux-arm-kernel@lists.infradead.org,
Mike Leach <mike.leach@linaro.org>
Subject: Re: [PATCHv2 2/4] coresight: tmc-etf: Fix NULL ptr dereference in tmc_enable_etf_sink_perf()
Date: Thu, 22 Oct 2020 18:19:37 +0530 [thread overview]
Message-ID: <a6eadc723ae52396a655c61b9f8d4eef@codeaurora.org> (raw)
In-Reply-To: <20201022113214.GD2611@hirez.programming.kicks-ass.net>
On 2020-10-22 17:02, Peter Zijlstra wrote:
> On Thu, Oct 22, 2020 at 04:27:52PM +0530, Sai Prakash Ranjan wrote:
>
>> Looking at the ETR and other places in the kernel, ETF and the
>> ETB are the only places trying to dereference the task(owner)
>> in tmc_enable_etf_sink_perf() which is also called from the
>> sched_in path as in the call trace.
>
>> @@ -391,6 +392,10 @@ static void *tmc_alloc_etf_buffer(struct
>> coresight_device *csdev,
>> {
>> int node;
>> struct cs_buffers *buf;
>> + struct task_struct *task = READ_ONCE(event->owner);
>> +
>> + if (!task || is_kernel_event(event))
>> + return NULL;
>
>
> This is *wrong*... why do you care about who owns the events?
>
The original issue was the owner being NULL and causing
a NULL pointer dereference. I did ask some time back
if it is valid for the owner to be NULL [1] and should
probably be handled in events core?
[1]
https://lore.kernel.org/lkml/c0e1f99a0a2480dfc8d788bb424d3f08@codeaurora.org/
Unable to handle kernel NULL pointer dereference at virtual address
0000000000000548
Mem abort info:
ESR = 0x96000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
Data abort info:
ISV = 0, ISS = 0x00000006
CM = 0, WnR = 0
<snip>...
Call trace:
tmc_enable_etf_sink+0xe4/0x280
coresight_enable_path+0x168/0x1fc
etm_event_start+0x8c/0xf8
etm_event_add+0x38/0x54
event_sched_in+0x194/0x2ac
group_sched_in+0x54/0x12c
flexible_sched_in+0xd8/0x120
visit_groups_merge+0x100/0x16c
ctx_flexible_sched_in+0x50/0x74
ctx_sched_in+0xa4/0xa8
perf_event_sched_in+0x60/0x6c
perf_event_context_sched_in+0x98/0xe0
__perf_event_task_sched_in+0x5c/0xd8
finish_task_switch+0x184/0x1cc
schedule_tail+0x20/0xec
ret_from_fork+0x4/0x18
Thanks,
Sai
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member
of Code Aurora Forum, hosted by The Linux Foundation
WARNING: multiple messages have this Message-ID (diff)
From: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
Mathieu Poirier <mathieu.poirier@linaro.org>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
linux-arm-msm@vger.kernel.org, coresight@lists.linaro.org,
linux-kernel@vger.kernel.org,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Stephen Boyd <swboyd@chromium.org>,
Ingo Molnar <mingo@redhat.com>,
Namhyung Kim <namhyung@kernel.org>, Jiri Olsa <jolsa@redhat.com>,
linux-arm-kernel@lists.infradead.org,
Mike Leach <mike.leach@linaro.org>
Subject: Re: [PATCHv2 2/4] coresight: tmc-etf: Fix NULL ptr dereference in tmc_enable_etf_sink_perf()
Date: Thu, 22 Oct 2020 18:19:37 +0530 [thread overview]
Message-ID: <a6eadc723ae52396a655c61b9f8d4eef@codeaurora.org> (raw)
In-Reply-To: <20201022113214.GD2611@hirez.programming.kicks-ass.net>
On 2020-10-22 17:02, Peter Zijlstra wrote:
> On Thu, Oct 22, 2020 at 04:27:52PM +0530, Sai Prakash Ranjan wrote:
>
>> Looking at the ETR and other places in the kernel, ETF and the
>> ETB are the only places trying to dereference the task(owner)
>> in tmc_enable_etf_sink_perf() which is also called from the
>> sched_in path as in the call trace.
>
>> @@ -391,6 +392,10 @@ static void *tmc_alloc_etf_buffer(struct
>> coresight_device *csdev,
>> {
>> int node;
>> struct cs_buffers *buf;
>> + struct task_struct *task = READ_ONCE(event->owner);
>> +
>> + if (!task || is_kernel_event(event))
>> + return NULL;
>
>
> This is *wrong*... why do you care about who owns the events?
>
The original issue was the owner being NULL and causing
a NULL pointer dereference. I did ask some time back
if it is valid for the owner to be NULL [1] and should
probably be handled in events core?
[1]
https://lore.kernel.org/lkml/c0e1f99a0a2480dfc8d788bb424d3f08@codeaurora.org/
Unable to handle kernel NULL pointer dereference at virtual address
0000000000000548
Mem abort info:
ESR = 0x96000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
Data abort info:
ISV = 0, ISS = 0x00000006
CM = 0, WnR = 0
<snip>...
Call trace:
tmc_enable_etf_sink+0xe4/0x280
coresight_enable_path+0x168/0x1fc
etm_event_start+0x8c/0xf8
etm_event_add+0x38/0x54
event_sched_in+0x194/0x2ac
group_sched_in+0x54/0x12c
flexible_sched_in+0xd8/0x120
visit_groups_merge+0x100/0x16c
ctx_flexible_sched_in+0x50/0x74
ctx_sched_in+0xa4/0xa8
perf_event_sched_in+0x60/0x6c
perf_event_context_sched_in+0x98/0xe0
__perf_event_task_sched_in+0x5c/0xd8
finish_task_switch+0x184/0x1cc
schedule_tail+0x20/0xec
ret_from_fork+0x4/0x18
Thanks,
Sai
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member
of Code Aurora Forum, hosted by The Linux Foundation
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linux-arm-kernel@lists.infradead.org
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next prev parent reply other threads:[~2020-10-22 12:49 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-22 10:57 [PATCHv2 0/4] coresight: etf/etb10/etr: Fix NULL pointer dereference crashes Sai Prakash Ranjan
2020-10-22 10:57 ` Sai Prakash Ranjan
2020-10-22 10:57 ` [PATCHv2 1/4] perf/core: Export is_kernel_event() Sai Prakash Ranjan
2020-10-22 10:57 ` Sai Prakash Ranjan
2020-10-31 7:35 ` kernel test robot
2020-10-22 10:57 ` [PATCHv2 2/4] coresight: tmc-etf: Fix NULL ptr dereference in tmc_enable_etf_sink_perf() Sai Prakash Ranjan
2020-10-22 10:57 ` Sai Prakash Ranjan
2020-10-22 11:32 ` Peter Zijlstra
2020-10-22 11:32 ` Peter Zijlstra
2020-10-22 12:49 ` Sai Prakash Ranjan [this message]
2020-10-22 12:49 ` Sai Prakash Ranjan
2020-10-22 13:34 ` Peter Zijlstra
2020-10-22 13:34 ` Peter Zijlstra
2020-10-22 14:23 ` Sai Prakash Ranjan
2020-10-22 14:23 ` Sai Prakash Ranjan
2020-10-22 13:30 ` Suzuki Poulose
2020-10-22 13:30 ` Suzuki Poulose
2020-10-22 15:06 ` Peter Zijlstra
2020-10-22 15:06 ` Peter Zijlstra
2020-10-22 15:32 ` Suzuki Poulose
2020-10-22 15:32 ` Suzuki Poulose
2020-10-22 21:20 ` Mathieu Poirier
2020-10-22 21:20 ` Mathieu Poirier
2020-10-23 7:39 ` Peter Zijlstra
2020-10-23 7:39 ` Peter Zijlstra
2020-10-23 8:49 ` Suzuki Poulose
2020-10-23 8:49 ` Suzuki Poulose
2020-10-23 9:23 ` Peter Zijlstra
2020-10-23 9:23 ` Peter Zijlstra
2020-10-23 10:49 ` Suzuki Poulose
2020-10-23 10:49 ` Suzuki Poulose
2020-10-23 9:41 ` Peter Zijlstra
2020-10-23 9:41 ` Peter Zijlstra
2020-10-23 10:34 ` Suzuki Poulose
2020-10-23 10:34 ` Suzuki Poulose
2020-10-23 10:54 ` Peter Zijlstra
2020-10-23 10:54 ` Peter Zijlstra
2020-10-23 12:56 ` Suzuki Poulose
2020-10-23 12:56 ` Suzuki Poulose
2020-10-23 13:16 ` Peter Zijlstra
2020-10-23 13:16 ` Peter Zijlstra
2020-10-23 13:29 ` Suzuki Poulose
2020-10-23 13:29 ` Suzuki Poulose
2020-10-23 13:44 ` Peter Zijlstra
2020-10-23 13:44 ` Peter Zijlstra
2020-10-23 20:37 ` Mathieu Poirier
2020-10-23 20:37 ` Mathieu Poirier
2020-10-30 7:59 ` Sai Prakash Ranjan
2020-10-30 7:59 ` Sai Prakash Ranjan
2020-10-30 16:48 ` Mathieu Poirier
2020-10-30 16:48 ` Mathieu Poirier
2020-10-30 17:26 ` Sai Prakash Ranjan
2020-10-30 17:26 ` Sai Prakash Ranjan
2020-11-04 17:03 ` Mathieu Poirier
2020-11-04 17:03 ` Mathieu Poirier
2020-10-22 10:57 ` [PATCHv2 3/4] coresight: etb10: Fix possible NULL ptr dereference in etb_enable_perf() Sai Prakash Ranjan
2020-10-22 10:57 ` Sai Prakash Ranjan
2020-10-22 10:57 ` [PATCHv2 4/4] coresight: tmc-etr: Fix possible NULL ptr dereference in get_perf_etr_buf_cpu_wide() Sai Prakash Ranjan
2020-10-22 10:57 ` Sai Prakash Ranjan
2020-10-22 11:10 ` [PATCHv2 0/4] coresight: etf/etb10/etr: Fix NULL pointer dereference crashes Sai Prakash Ranjan
2020-10-22 11:10 ` Sai Prakash Ranjan
2020-10-22 11:23 ` Sai Prakash Ranjan
2020-10-22 11:23 ` Sai Prakash Ranjan
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