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From: Sean Anderson <sean.anderson@linux.dev>
To: Manish Narani <manish.narani@xilinx.com>,
	Anand Ashok Dumbre <anand.ashok.dumbre@xilinx.com>,
	linux-iio@vger.kernel.org
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Subject: iio: xilinx-ams: shift-out-of-bounds in ams_enable_channel_sequence
Date: Tue, 5 Mar 2024 12:30:53 -0500	[thread overview]
Message-ID: <a6dd3a2f-c3e9-4781-801b-8e8e72ac9beb@linux.dev> (raw)

Hi,

When enabling UBSAN on a ZynqMP Ultrascale+, I see the following error during boot:

[    1.447628] ================================================================================
[    1.447832] UBSAN: shift-out-of-bounds in ../drivers/iio/adc/xilinx-ams.c:426:16
[    1.448019] shift exponent 66 is too large for 64-bit type 'long long unsigned int'
[    1.448211] CPU: 2 PID: 1 Comm: swapper/0 Not tainted 6.6.20+ #90
[    1.448368] Hardware name: xlnx,zynqmp (DT)
[    1.448475] Call trace:
[    1.448547]  dump_backtrace+0x9c/0x11c
[    1.448655]  show_stack+0x18/0x24
[    1.448749]  dump_stack_lvl+0xac/0xd4
[    1.448853]  dump_stack+0x18/0x24
[    1.448947]  ubsan_epilogue+0x10/0x44
[    1.449051]  __ubsan_handle_shift_out_of_bounds+0x98/0x134
[    1.449191]  ams_enable_channel_sequence+0x22c/0x23c
[    1.449324]  ams_probe+0x570/0x6d4
[    1.449423]  platform_probe+0x68/0x108
[    1.449530]  really_probe+0x158/0x3b0
[    1.449632]  __driver_probe_device+0x88/0x1a0
[    1.449747]  driver_probe_device+0x3c/0x138
[    1.449859]  __driver_attach+0xe4/0x1bc
[    1.449964]  bus_for_each_dev+0x78/0xe0
[    1.450068]  driver_attach+0x24/0x30
[    1.450167]  bus_add_driver+0x110/0x240
[    1.450271]  driver_register+0x60/0x128
[    1.450376]  __platform_driver_register+0x28/0x34
[    1.450500]  ams_driver_init+0x1c/0x28
[    1.450609]  do_one_initcall+0x78/0x2c8
[    1.450714]  kernel_init_freeable+0x2f8/0x59c
[    1.450831]  kernel_init+0x30/0x150
[    1.450932]  ret_from_fork+0x10/0x20
[    1.451073] ================================================================================

When applying the following patch:

diff --git a/drivers/iio/adc/xilinx-ams.c b/drivers/iio/adc/xilinx-ams.c
index f0b71a1220e0..1ced8cff461a 100644
--- a/drivers/iio/adc/xilinx-ams.c
+++ b/drivers/iio/adc/xilinx-ams.c
@@ -414,8 +414,17 @@ static void ams_enable_channel_sequence(struct iio_dev *indio_dev)
 
        /* Run calibration of PS & PL as part of the sequence */
        scan_mask = BIT(0) | BIT(AMS_PS_SEQ_MAX);
-       for (i = 0; i < indio_dev->num_channels; i++)
+       for (i = 0; i < indio_dev->num_channels; i++) {
+               if (indio_dev->channels[i].scan_index >= 64) {
+                       const struct iio_chan_spec *chan = &indio_dev->channels[i];
+
+                       dev_warn(&indio_dev->dev,
+                                "channel %d (%d %d.%d @ %lx) has scan_index %d\n",
+                                i, chan->type, chan->channel, chan->channel2,
+                                chan->address, chan->scan_index);
+               }
                scan_mask |= BIT_ULL(indio_dev->channels[i].scan_index);
+       }
 
        if (ams->ps_base) {
                /* put sysmon in a soft reset to change the sequence */

I see these additional outputs:

[    1.447457] iio iio:device0: channel 0 (0 0.0 @ 60) has scan_index 66
[    1.451280] iio iio:device0: channel 1 (0 1.0 @ 6c) has scan_index 67
[    1.451446] iio iio:device0: channel 2 (0 2.0 @ 78) has scan_index 68
[    1.451612] iio iio:device0: channel 3 (0 3.0 @ 7c) has scan_index 69
[    1.451777] iio iio:device0: channel 4 (0 4.0 @ 80) has scan_index 70
[    1.451942] iio iio:device0: channel 5 (0 5.0 @ 84) has scan_index 71
[    1.452107] iio iio:device0: channel 6 (0 6.0 @ 9c) has scan_index 72

Indicating that the issue is with the ams_ctrl_channels using the
AMS_CTRL_CHAN_VOLTAGE macro.

--Sean

             reply	other threads:[~2024-03-05 17:30 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-05 17:30 Sean Anderson [this message]
2024-03-09 19:06 ` iio: xilinx-ams: shift-out-of-bounds in ams_enable_channel_sequence Jonathan Cameron
2024-03-11 16:11   ` Sean Anderson
2024-03-11 16:30     ` Sean Anderson

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