Re: [RFC PATCH] coresight: dynamic-replicator: Fix handling of multiple connections

From: Sai Prakash Ranjan
Date: Tue Apr 07 2020 - 09:56:55 EST

Hi Suzuki,

On 2020-04-07 18:38, Suzuki K Poulose wrote:
On 04/07/2020 12:29 PM, Sai Prakash Ranjan wrote:
Hi Suzuki,

Thanks for looking into this issue.

On 2020-04-07 15:54, Suzuki K Poulose wrote:
On 04/07/2020 10:46 AM, Sai Prakash Ranjan wrote:

There seems to be two replicators back to back here. What is connected
to the other output of both of them ? Are there any TPIUs ? What happens
if you choose a sink on the other end of "swao_replicator" (ETB ?)


The other outport of swao replicator is connected to EUD which is a
QCOM specific HW which can be used as a sink like USB.
And the other outport of other replicator(replicator_out) is connected to
TPIU.

After boot, what do the idfilter registers read for both the replicators ?


Added some prints in replicator_probe.

Âreplicator probe ret=-517 devname=6046000.replicator idfilter0=0x0 idfilter1=0x0
Âreplicator probe ret=0 devname=6b06000.replicator idfilter0=0xff idfilter1=0xff
Âreplicator probe ret=0 devname=6046000.replicator idfilter0=0xff idfilter1=0xff

Curious to see how the idfilterX is set to 0:
if that is never used.
Or
if the user doesn't reset it back to 0xff.


For both replicators, the default value seems to be 0x0.

replicator probe in res ret=0 devname=6046000.replicator idfilter0=0x0 idfilter1=0x0
replicator probe ret=-517 devname=6046000.replicator idfilter0=0x0 idfilter1=0x0
replicator probe in res ret=0 devname=6b06000.replicator idfilter0=0x0 idfilter1=0x0
replicator probe ret=0 devname=6b06000.replicator idfilter0=0xff idfilter1=0xff
replicator probe in res ret=0 devname=6046000.replicator idfilter0=0x0 idfilter1=0x0
replicator probe ret=0 devname=6046000.replicator idfilter0=0xff idfilter1=0xff

Does your test ever touch EUD (enable the port for EUD at
swao-replicator) ? What are the values before you run your test ?



No, we do not use EUD, downstream it is used as dummy sink.
And I just try to select the ETR as the sink and enable ETM0 as the trace source.

echo 1 > /sys/bus/coresight/devices/tmc_etr0/enable_sink
echo 1 > /sys/bus/coresight/devices/etm0/enable_source

Also I see the KASAN warning but that seems like some other issue.

[ 526.110401] ==================================================================
[ 526.117988] BUG: KASAN: slab-out-of-bounds in funnel_enable+0x54/0x1b0
[ 526.124706] Read of size 4 at addr ffffff8135f9549c by task bash/1114
[ 526.131324]
[ 526.132886] CPU: 3 PID: 1114 Comm: bash Tainted: G S 5.4.25 #232
[ 526.140397] Hardware name: Qualcomm Technologies, Inc. SC7180 IDP (DT)
[ 526.147113] Call trace:
[ 526.149653] dump_backtrace+0x0/0x188
[ 526.153431] show_stack+0x20/0x2c
[ 526.156852] dump_stack+0xdc/0x144
[ 526.160370] print_address_description+0x3c/0x494
[ 526.165211] __kasan_report+0x144/0x168
[ 526.169170] kasan_report+0x10/0x18
[ 526.172769] check_memory_region+0x1a4/0x1b4
[ 526.177164] __kasan_check_read+0x18/0x24
[ 526.181292] funnel_enable+0x54/0x1b0
[ 526.185072] coresight_enable_path+0x104/0x198
[ 526.189649] coresight_enable+0x118/0x26c
[ 526.193778] enable_source_store+0x64/0xa8
[ 526.198007] dev_attr_store+0x40/0x58
[ 526.201788] sysfs_kf_write+0x4c/0x64
[ 526.205567] kernfs_fop_write+0x16c/0x210
[ 526.209700] __vfs_write+0x54/0x1a8
[ 526.213297] vfs_write+0xe4/0x1a4
[ 526.216714] ksys_write+0x84/0xec
[ 526.220131] __arm64_sys_write+0x20/0x2c
[ 526.224179] el0_svc_common+0xa8/0x160
[ 526.228040] el0_svc_compat_handler+0x2c/0x38
[ 526.232533] el0_svc_compat+0x8/0x10
[ 526.236225]
[ 526.237782] Allocated by task 280:
[ 526.241298] __kasan_kmalloc+0xf0/0x1ac
[ 526.245249] kasan_kmalloc+0xc/0x14
[ 526.248849] __kmalloc+0x28c/0x3b4
[ 526.252361] coresight_register+0x88/0x250
[ 526.256587] funnel_probe+0x15c/0x228
[ 526.260365] dynamic_funnel_probe+0x20/0x2c
[ 526.264679] amba_probe+0xbc/0x158
[ 526.268193] really_probe+0x144/0x408
[ 526.271970] driver_probe_device+0x70/0x140
[ 526.276282] __device_attach_driver+0x9c/0x110
[ 526.280861] bus_for_each_drv+0x90/0xd8
[ 526.284822] __device_attach+0xb4/0x164
[ 526.288772] device_initial_probe+0x20/0x2c
[ 526.293081] bus_probe_device+0x34/0x94
[ 526.297030] deferred_probe_work_func+0xa4/0x100
[ 526.301794] process_one_work+0x33c/0x640
[ 526.305922] worker_thread+0x2a0/0x470
[ 526.309786] kthread+0x128/0x138
[ 526.313119] ret_from_fork+0x10/0x18
[ 526.316810]
[ 526.318364] Freed by task 0:
[ 526.321344] (stack is not available)
[ 526.325024]
[ 526.326580] The buggy address belongs to the object at ffffff8135f95480
[ 526.326580] which belongs to the cache kmalloc-128 of size 128
[ 526.339439] The buggy address is located 28 bytes inside of
[ 526.339439] 128-byte region [ffffff8135f95480, ffffff8135f95500)
[ 526.351399] The buggy address belongs to the page:
[ 526.356342] page:ffffffff04b7e500 refcount:1 mapcount:0 mapping:ffffff814b00c380 index:0x0 compound_mapcount: 0
[ 526.366711] flags: 0x4000000000010200(slab|head)
[ 526.371475] raw: 4000000000010200 ffffffff05034008 ffffffff0501eb08 ffffff814b00c380
[ 526.379435] raw: 0000000000000000 0000000000190019 00000001ffffffff 0000000000000000
[ 526.387393] page dumped because: kasan: bad access detected
[ 526.393128]
[ 526.394681] Memory state around the buggy address:
[ 526.399619] ffffff8135f95380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 526.407046] ffffff8135f95400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 526.414473] >ffffff8135f95480: 04 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 526.421900] ^
[ 526.426029] ffffff8135f95500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 526.433456] ffffff8135f95580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 526.440883] ==================================================================

Thanks,
Sai

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