]> git.ipfire.org Git - thirdparty/kernel/stable-queue.git/commitdiff
5.4-stable patches
authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Mon, 21 Jul 2025 11:24:07 +0000 (13:24 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Mon, 21 Jul 2025 11:24:07 +0000 (13:24 +0200)
added patches:
comedi-pcl812-fix-bit-shift-out-of-bounds.patch
iio-adc-max1363-fix-max1363_4x_chans-max1363_8x_chans.patch
iio-adc-max1363-reorder-mode_list-entries.patch
iio-adc-stm32-adc-fix-race-in-installing-chained-irq-handler.patch
soc-aspeed-lpc-snoop-cleanup-resources-in-stack-order.patch
soc-aspeed-lpc-snoop-don-t-disable-channels-that-aren-t-enabled.patch

queue-5.4/comedi-pcl812-fix-bit-shift-out-of-bounds.patch [new file with mode: 0644]
queue-5.4/iio-adc-max1363-fix-max1363_4x_chans-max1363_8x_chans.patch [new file with mode: 0644]
queue-5.4/iio-adc-max1363-reorder-mode_list-entries.patch [new file with mode: 0644]
queue-5.4/iio-adc-stm32-adc-fix-race-in-installing-chained-irq-handler.patch [new file with mode: 0644]
queue-5.4/series
queue-5.4/soc-aspeed-lpc-snoop-cleanup-resources-in-stack-order.patch [new file with mode: 0644]
queue-5.4/soc-aspeed-lpc-snoop-don-t-disable-channels-that-aren-t-enabled.patch [new file with mode: 0644]

diff --git a/queue-5.4/comedi-pcl812-fix-bit-shift-out-of-bounds.patch b/queue-5.4/comedi-pcl812-fix-bit-shift-out-of-bounds.patch
new file mode 100644 (file)
index 0000000..91afe52
--- /dev/null
@@ -0,0 +1,43 @@
+From b14b076ce593f72585412fc7fd3747e03a5e3632 Mon Sep 17 00:00:00 2001
+From: Ian Abbott <abbotti@mev.co.uk>
+Date: Mon, 7 Jul 2025 14:34:29 +0100
+Subject: comedi: pcl812: Fix bit shift out of bounds
+
+From: Ian Abbott <abbotti@mev.co.uk>
+
+commit b14b076ce593f72585412fc7fd3747e03a5e3632 upstream.
+
+When checking for a supported IRQ number, the following test is used:
+
+       if ((1 << it->options[1]) & board->irq_bits) {
+
+However, `it->options[i]` is an unchecked `int` value from userspace, so
+the shift amount could be negative or out of bounds.  Fix the test by
+requiring `it->options[1]` to be within bounds before proceeding with
+the original test.  Valid `it->options[1]` values that select the IRQ
+will be in the range [1,15]. The value 0 explicitly disables the use of
+interrupts.
+
+Reported-by: syzbot+32de323b0addb9e114ff@syzkaller.appspotmail.com
+Closes: https://syzkaller.appspot.com/bug?extid=32de323b0addb9e114ff
+Fixes: fcdb427bc7cf ("Staging: comedi: add pcl821 driver")
+Cc: stable@vger.kernel.org # 5.13+
+Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
+Link: https://lore.kernel.org/r/20250707133429.73202-1-abbotti@mev.co.uk
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/staging/comedi/drivers/pcl812.c |    3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+--- a/drivers/staging/comedi/drivers/pcl812.c
++++ b/drivers/staging/comedi/drivers/pcl812.c
+@@ -1151,7 +1151,8 @@ static int pcl812_attach(struct comedi_d
+               if (!dev->pacer)
+                       return -ENOMEM;
+-              if ((1 << it->options[1]) & board->irq_bits) {
++              if (it->options[1] > 0 && it->options[1] < 16 &&
++                  (1 << it->options[1]) & board->irq_bits) {
+                       ret = request_irq(it->options[1], pcl812_interrupt, 0,
+                                         dev->board_name, dev);
+                       if (ret == 0)
diff --git a/queue-5.4/iio-adc-max1363-fix-max1363_4x_chans-max1363_8x_chans.patch b/queue-5.4/iio-adc-max1363-fix-max1363_4x_chans-max1363_8x_chans.patch
new file mode 100644 (file)
index 0000000..1e59035
--- /dev/null
@@ -0,0 +1,93 @@
+From 6d21f2c2dd843bceefd9455f2919f6bb526797f0 Mon Sep 17 00:00:00 2001
+From: Fabio Estevam <festevam@denx.de>
+Date: Fri, 16 May 2025 14:38:59 -0300
+Subject: iio: adc: max1363: Fix MAX1363_4X_CHANS/MAX1363_8X_CHANS[]
+
+From: Fabio Estevam <festevam@denx.de>
+
+commit 6d21f2c2dd843bceefd9455f2919f6bb526797f0 upstream.
+
+Since commit 2718f15403fb ("iio: sanity check available_scan_masks array"),
+booting a board populated with a MAX11601 results in a flood of warnings:
+
+max1363 1-0064: available_scan_mask 8 subset of 0. Never used
+max1363 1-0064: available_scan_mask 9 subset of 0. Never used
+max1363 1-0064: available_scan_mask 10 subset of 0. Never used
+max1363 1-0064: available_scan_mask 11 subset of 0. Never used
+max1363 1-0064: available_scan_mask 12 subset of 0. Never used
+max1363 1-0064: available_scan_mask 13 subset of 0. Never used
+...
+
+These warnings are caused by incorrect offsets used for differential
+channels in the MAX1363_4X_CHANS() and MAX1363_8X_CHANS() macros.
+
+The max1363_mode_table[] defines the differential channel mappings as
+follows:
+
+MAX1363_MODE_DIFF_SINGLE(0, 1, 1 << 12),
+MAX1363_MODE_DIFF_SINGLE(2, 3, 1 << 13),
+MAX1363_MODE_DIFF_SINGLE(4, 5, 1 << 14),
+MAX1363_MODE_DIFF_SINGLE(6, 7, 1 << 15),
+MAX1363_MODE_DIFF_SINGLE(8, 9, 1 << 16),
+MAX1363_MODE_DIFF_SINGLE(10, 11, 1 << 17),
+MAX1363_MODE_DIFF_SINGLE(1, 0, 1 << 18),
+MAX1363_MODE_DIFF_SINGLE(3, 2, 1 << 19),
+MAX1363_MODE_DIFF_SINGLE(5, 4, 1 << 20),
+MAX1363_MODE_DIFF_SINGLE(7, 6, 1 << 21),
+MAX1363_MODE_DIFF_SINGLE(9, 8, 1 << 22),
+MAX1363_MODE_DIFF_SINGLE(11, 10, 1 << 23),
+
+Update the macros to follow this same pattern, ensuring that the scan masks
+are valid and preventing the warnings.
+
+Cc: stable@vger.kernel.org
+Suggested-by: Jonathan Cameron <jic23@kernel.org>
+Signed-off-by: Fabio Estevam <festevam@denx.de>
+Acked-by: Matti Vaittinen <mazziesaccount@gmail.com>
+Link: https://patch.msgid.link/20250516173900.677821-1-festevam@gmail.com
+Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/iio/adc/max1363.c |   24 ++++++++++++------------
+ 1 file changed, 12 insertions(+), 12 deletions(-)
+
+--- a/drivers/iio/adc/max1363.c
++++ b/drivers/iio/adc/max1363.c
+@@ -505,10 +505,10 @@ static const struct iio_event_spec max13
+       MAX1363_CHAN_U(1, _s1, 1, bits, ev_spec, num_ev_spec),          \
+       MAX1363_CHAN_U(2, _s2, 2, bits, ev_spec, num_ev_spec),          \
+       MAX1363_CHAN_U(3, _s3, 3, bits, ev_spec, num_ev_spec),          \
+-      MAX1363_CHAN_B(0, 1, d0m1, 4, bits, ev_spec, num_ev_spec),      \
+-      MAX1363_CHAN_B(2, 3, d2m3, 5, bits, ev_spec, num_ev_spec),      \
+-      MAX1363_CHAN_B(1, 0, d1m0, 6, bits, ev_spec, num_ev_spec),      \
+-      MAX1363_CHAN_B(3, 2, d3m2, 7, bits, ev_spec, num_ev_spec),      \
++      MAX1363_CHAN_B(0, 1, d0m1, 12, bits, ev_spec, num_ev_spec),     \
++      MAX1363_CHAN_B(2, 3, d2m3, 13, bits, ev_spec, num_ev_spec),     \
++      MAX1363_CHAN_B(1, 0, d1m0, 18, bits, ev_spec, num_ev_spec),     \
++      MAX1363_CHAN_B(3, 2, d3m2, 19, bits, ev_spec, num_ev_spec),     \
+       IIO_CHAN_SOFT_TIMESTAMP(8)                                      \
+       }
+@@ -603,14 +603,14 @@ static const enum max1363_modes max11608
+       MAX1363_CHAN_U(5, _s5, 5, bits, NULL, 0),       \
+       MAX1363_CHAN_U(6, _s6, 6, bits, NULL, 0),       \
+       MAX1363_CHAN_U(7, _s7, 7, bits, NULL, 0),       \
+-      MAX1363_CHAN_B(0, 1, d0m1, 8, bits, NULL, 0),   \
+-      MAX1363_CHAN_B(2, 3, d2m3, 9, bits, NULL, 0),   \
+-      MAX1363_CHAN_B(4, 5, d4m5, 10, bits, NULL, 0),  \
+-      MAX1363_CHAN_B(6, 7, d6m7, 11, bits, NULL, 0),  \
+-      MAX1363_CHAN_B(1, 0, d1m0, 12, bits, NULL, 0),  \
+-      MAX1363_CHAN_B(3, 2, d3m2, 13, bits, NULL, 0),  \
+-      MAX1363_CHAN_B(5, 4, d5m4, 14, bits, NULL, 0),  \
+-      MAX1363_CHAN_B(7, 6, d7m6, 15, bits, NULL, 0),  \
++      MAX1363_CHAN_B(0, 1, d0m1, 12, bits, NULL, 0),  \
++      MAX1363_CHAN_B(2, 3, d2m3, 13, bits, NULL, 0),  \
++      MAX1363_CHAN_B(4, 5, d4m5, 14, bits, NULL, 0),  \
++      MAX1363_CHAN_B(6, 7, d6m7, 15, bits, NULL, 0),  \
++      MAX1363_CHAN_B(1, 0, d1m0, 18, bits, NULL, 0),  \
++      MAX1363_CHAN_B(3, 2, d3m2, 19, bits, NULL, 0),  \
++      MAX1363_CHAN_B(5, 4, d5m4, 20, bits, NULL, 0),  \
++      MAX1363_CHAN_B(7, 6, d7m6, 21, bits, NULL, 0),  \
+       IIO_CHAN_SOFT_TIMESTAMP(16)                     \
+ }
+ static const struct iio_chan_spec max11602_channels[] = MAX1363_8X_CHANS(8);
diff --git a/queue-5.4/iio-adc-max1363-reorder-mode_list-entries.patch b/queue-5.4/iio-adc-max1363-reorder-mode_list-entries.patch
new file mode 100644 (file)
index 0000000..b864af3
--- /dev/null
@@ -0,0 +1,91 @@
+From 8d8d7c1dbc46aa07a76acab7336a42ddd900be10 Mon Sep 17 00:00:00 2001
+From: Fabio Estevam <festevam@denx.de>
+Date: Fri, 16 May 2025 14:39:00 -0300
+Subject: iio: adc: max1363: Reorder mode_list[] entries
+
+From: Fabio Estevam <festevam@denx.de>
+
+commit 8d8d7c1dbc46aa07a76acab7336a42ddd900be10 upstream.
+
+The IIO core issues warnings when a scan mask is a subset of a previous
+entry in the available_scan_masks array.
+
+On a board using a MAX11601, the following warning is observed:
+
+max1363 1-0064: available_scan_mask 7 subset of 6. Never used
+
+This occurs because the entries in the max11607_mode_list[] array are not
+ordered correctly. To fix this, reorder the entries so that no scan mask is
+a subset of an earlier one.
+
+While at it, reorder the mode_list[] arrays for other supported chips as
+well, to prevent similar warnings on different variants.
+
+Note fixes tag dropped as these were introduced over many commits a long
+time back and the side effect until recently was a reduction in sampling
+rate due to reading too many channels when only a few were desired.
+Now we have a sanity check that reports this error but that is not
+where the issue was introduced.
+
+Cc: stable@vger.kernel.org
+Signed-off-by: Fabio Estevam <festevam@denx.de>
+Acked-by: Matti Vaittinen <mazziesaccount@gmail.com>
+Link: https://patch.msgid.link/20250516173900.677821-2-festevam@gmail.com
+Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/iio/adc/max1363.c |   19 +++++++++----------
+ 1 file changed, 9 insertions(+), 10 deletions(-)
+
+--- a/drivers/iio/adc/max1363.c
++++ b/drivers/iio/adc/max1363.c
+@@ -526,23 +526,23 @@ static const struct iio_chan_spec max136
+ /* Applies to max1236, max1237 */
+ static const enum max1363_modes max1236_mode_list[] = {
+       _s0, _s1, _s2, _s3,
+-      s0to1, s0to2, s0to3,
++      s0to1, s0to2, s2to3, s0to3,
+       d0m1, d2m3, d1m0, d3m2,
+       d0m1to2m3, d1m0to3m2,
+-      s2to3,
+ };
+ /* Applies to max1238, max1239 */
+ static const enum max1363_modes max1238_mode_list[] = {
+       _s0, _s1, _s2, _s3, _s4, _s5, _s6, _s7, _s8, _s9, _s10, _s11,
+       s0to1, s0to2, s0to3, s0to4, s0to5, s0to6,
++      s6to7, s6to8, s6to9, s6to10, s6to11,
+       s0to7, s0to8, s0to9, s0to10, s0to11,
+       d0m1, d2m3, d4m5, d6m7, d8m9, d10m11,
+       d1m0, d3m2, d5m4, d7m6, d9m8, d11m10,
+-      d0m1to2m3, d0m1to4m5, d0m1to6m7, d0m1to8m9, d0m1to10m11,
+-      d1m0to3m2, d1m0to5m4, d1m0to7m6, d1m0to9m8, d1m0to11m10,
+-      s6to7, s6to8, s6to9, s6to10, s6to11,
+-      d6m7to8m9, d6m7to10m11, d7m6to9m8, d7m6to11m10,
++      d0m1to2m3, d0m1to4m5, d0m1to6m7, d6m7to8m9,
++      d0m1to8m9, d6m7to10m11, d0m1to10m11, d1m0to3m2,
++      d1m0to5m4, d1m0to7m6, d7m6to9m8, d1m0to9m8,
++      d7m6to11m10, d1m0to11m10,
+ };
+ #define MAX1363_12X_CHANS(bits) {                             \
+@@ -578,16 +578,15 @@ static const struct iio_chan_spec max123
+ static const enum max1363_modes max11607_mode_list[] = {
+       _s0, _s1, _s2, _s3,
+-      s0to1, s0to2, s0to3,
+-      s2to3,
++      s0to1, s0to2, s2to3,
++      s0to3,
+       d0m1, d2m3, d1m0, d3m2,
+       d0m1to2m3, d1m0to3m2,
+ };
+ static const enum max1363_modes max11608_mode_list[] = {
+       _s0, _s1, _s2, _s3, _s4, _s5, _s6, _s7,
+-      s0to1, s0to2, s0to3, s0to4, s0to5, s0to6, s0to7,
+-      s6to7,
++      s0to1, s0to2, s0to3, s0to4, s0to5, s0to6, s6to7, s0to7,
+       d0m1, d2m3, d4m5, d6m7,
+       d1m0, d3m2, d5m4, d7m6,
+       d0m1to2m3, d0m1to4m5, d0m1to6m7,
diff --git a/queue-5.4/iio-adc-stm32-adc-fix-race-in-installing-chained-irq-handler.patch b/queue-5.4/iio-adc-stm32-adc-fix-race-in-installing-chained-irq-handler.patch
new file mode 100644 (file)
index 0000000..b8cece6
--- /dev/null
@@ -0,0 +1,45 @@
+From e8ad595064f6ebd5d2d1a5d5d7ebe0efce623091 Mon Sep 17 00:00:00 2001
+From: Chen Ni <nichen@iscas.ac.cn>
+Date: Thu, 15 May 2025 16:31:01 +0800
+Subject: iio: adc: stm32-adc: Fix race in installing chained IRQ handler
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+From: Chen Ni <nichen@iscas.ac.cn>
+
+commit e8ad595064f6ebd5d2d1a5d5d7ebe0efce623091 upstream.
+
+Fix a race where a pending interrupt could be received and the handler
+called before the handler's data has been setup, by converting to
+irq_set_chained_handler_and_data().
+
+Fixes: 1add69880240 ("iio: adc: Add support for STM32 ADC core")
+Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
+Reviewed-by: Nuno Sá <nuno.sa@analog.com>
+Tested-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
+Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
+Link: https://patch.msgid.link/20250515083101.3811350-1-nichen@iscas.ac.cn
+Cc: <Stable@vger.kernel.org>
+Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/iio/adc/stm32-adc-core.c |    7 +++----
+ 1 file changed, 3 insertions(+), 4 deletions(-)
+
+--- a/drivers/iio/adc/stm32-adc-core.c
++++ b/drivers/iio/adc/stm32-adc-core.c
+@@ -393,10 +393,9 @@ static int stm32_adc_irq_probe(struct pl
+               return -ENOMEM;
+       }
+-      for (i = 0; i < priv->cfg->num_irqs; i++) {
+-              irq_set_chained_handler(priv->irq[i], stm32_adc_irq_handler);
+-              irq_set_handler_data(priv->irq[i], priv);
+-      }
++      for (i = 0; i < priv->cfg->num_irqs; i++)
++              irq_set_chained_handler_and_data(priv->irq[i],
++                                               stm32_adc_irq_handler, priv);
+       return 0;
+ }
index 2a028ee50b82044b40e1769e3c881efc3ed21e06..37d678ace03b8ce90e4da9b90df44b8d25e236b0 100644 (file)
@@ -17,3 +17,9 @@ memstick-core-zero-initialize-id_reg-in-h_memstick_read_dev_id.patch
 mmc-bcm2835-fix-dma_unmap_sg-nents-value.patch
 mmc-sdhci-pci-quirk-for-broken-command-queuing-on-intel-glk-based-positivo-models.patch
 mmc-sdhci_am654-workaround-for-errata-i2312.patch
+soc-aspeed-lpc-snoop-cleanup-resources-in-stack-order.patch
+soc-aspeed-lpc-snoop-don-t-disable-channels-that-aren-t-enabled.patch
+iio-adc-max1363-fix-max1363_4x_chans-max1363_8x_chans.patch
+iio-adc-max1363-reorder-mode_list-entries.patch
+iio-adc-stm32-adc-fix-race-in-installing-chained-irq-handler.patch
+comedi-pcl812-fix-bit-shift-out-of-bounds.patch
diff --git a/queue-5.4/soc-aspeed-lpc-snoop-cleanup-resources-in-stack-order.patch b/queue-5.4/soc-aspeed-lpc-snoop-cleanup-resources-in-stack-order.patch
new file mode 100644 (file)
index 0000000..3039d63
--- /dev/null
@@ -0,0 +1,36 @@
+From 8481d59be606d2338dbfe14b04cdbd1a3402c150 Mon Sep 17 00:00:00 2001
+From: Andrew Jeffery <andrew@codeconstruct.com.au>
+Date: Mon, 16 Jun 2025 22:43:38 +0930
+Subject: soc: aspeed: lpc-snoop: Cleanup resources in stack-order
+
+From: Andrew Jeffery <andrew@codeconstruct.com.au>
+
+commit 8481d59be606d2338dbfe14b04cdbd1a3402c150 upstream.
+
+Free the kfifo after unregistering the miscdev in
+aspeed_lpc_disable_snoop() as the kfifo is initialised before the
+miscdev in aspeed_lpc_enable_snoop().
+
+Fixes: 3772e5da4454 ("drivers/misc: Aspeed LPC snoop output using misc chardev")
+Cc: stable@vger.kernel.org
+Cc: Jean Delvare <jdelvare@suse.de>
+Acked-by: Jean Delvare <jdelvare@suse.de>
+Link: https://patch.msgid.link/20250616-aspeed-lpc-snoop-fixes-v2-1-3cdd59c934d3@codeconstruct.com.au
+Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/soc/aspeed/aspeed-lpc-snoop.c |    2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/drivers/soc/aspeed/aspeed-lpc-snoop.c
++++ b/drivers/soc/aspeed/aspeed-lpc-snoop.c
+@@ -265,8 +265,8 @@ static void aspeed_lpc_disable_snoop(str
+               return;
+       }
+-      kfifo_free(&lpc_snoop->chan[channel].fifo);
+       misc_deregister(&lpc_snoop->chan[channel].miscdev);
++      kfifo_free(&lpc_snoop->chan[channel].fifo);
+ }
+ static int aspeed_lpc_snoop_probe(struct platform_device *pdev)
diff --git a/queue-5.4/soc-aspeed-lpc-snoop-don-t-disable-channels-that-aren-t-enabled.patch b/queue-5.4/soc-aspeed-lpc-snoop-don-t-disable-channels-that-aren-t-enabled.patch
new file mode 100644 (file)
index 0000000..1760871
--- /dev/null
@@ -0,0 +1,83 @@
+From 56448e78a6bb4e1a8528a0e2efe94eff0400c247 Mon Sep 17 00:00:00 2001
+From: Andrew Jeffery <andrew@codeconstruct.com.au>
+Date: Mon, 16 Jun 2025 22:43:39 +0930
+Subject: soc: aspeed: lpc-snoop: Don't disable channels that aren't enabled
+
+From: Andrew Jeffery <andrew@codeconstruct.com.au>
+
+commit 56448e78a6bb4e1a8528a0e2efe94eff0400c247 upstream.
+
+Mitigate e.g. the following:
+
+    # echo 1e789080.lpc-snoop > /sys/bus/platform/drivers/aspeed-lpc-snoop/unbind
+    ...
+    [  120.363594] Unable to handle kernel NULL pointer dereference at virtual address 00000004 when write
+    [  120.373866] [00000004] *pgd=00000000
+    [  120.377910] Internal error: Oops: 805 [#1] SMP ARM
+    [  120.383306] CPU: 1 UID: 0 PID: 315 Comm: sh Not tainted 6.15.0-rc1-00009-g926217bc7d7d-dirty #20 NONE
+    ...
+    [  120.679543] Call trace:
+    [  120.679559]  misc_deregister from aspeed_lpc_snoop_remove+0x84/0xac
+    [  120.692462]  aspeed_lpc_snoop_remove from platform_remove+0x28/0x38
+    [  120.700996]  platform_remove from device_release_driver_internal+0x188/0x200
+    ...
+
+Fixes: 9f4f9ae81d0a ("drivers/misc: add Aspeed LPC snoop driver")
+Cc: stable@vger.kernel.org
+Cc: Jean Delvare <jdelvare@suse.de>
+Acked-by: Jean Delvare <jdelvare@suse.de>
+Link: https://patch.msgid.link/20250616-aspeed-lpc-snoop-fixes-v2-2-3cdd59c934d3@codeconstruct.com.au
+Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/soc/aspeed/aspeed-lpc-snoop.c |   11 +++++++++++
+ 1 file changed, 11 insertions(+)
+
+--- a/drivers/soc/aspeed/aspeed-lpc-snoop.c
++++ b/drivers/soc/aspeed/aspeed-lpc-snoop.c
+@@ -60,6 +60,7 @@ struct aspeed_lpc_snoop_model_data {
+ };
+ struct aspeed_lpc_snoop_channel {
++      bool enabled;
+       struct kfifo            fifo;
+       wait_queue_head_t       wq;
+       struct miscdevice       miscdev;
+@@ -192,6 +193,9 @@ static int aspeed_lpc_enable_snoop(struc
+       const struct aspeed_lpc_snoop_model_data *model_data =
+               of_device_get_match_data(dev);
++      if (WARN_ON(lpc_snoop->chan[channel].enabled))
++              return -EBUSY;
++
+       init_waitqueue_head(&lpc_snoop->chan[channel].wq);
+       /* Create FIFO datastructure */
+       rc = kfifo_alloc(&lpc_snoop->chan[channel].fifo,
+@@ -238,6 +242,8 @@ static int aspeed_lpc_enable_snoop(struc
+               regmap_update_bits(lpc_snoop->regmap, HICRB,
+                               hicrb_en, hicrb_en);
++      lpc_snoop->chan[channel].enabled = true;
++
+       return 0;
+ err_misc_deregister:
+@@ -250,6 +256,9 @@ err_free_fifo:
+ static void aspeed_lpc_disable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
+                                    int channel)
+ {
++      if (!lpc_snoop->chan[channel].enabled)
++              return;
++
+       switch (channel) {
+       case 0:
+               regmap_update_bits(lpc_snoop->regmap, HICR5,
+@@ -265,6 +274,8 @@ static void aspeed_lpc_disable_snoop(str
+               return;
+       }
++      lpc_snoop->chan[channel].enabled = false;
++      /* Consider improving safety wrt concurrent reader(s) */
+       misc_deregister(&lpc_snoop->chan[channel].miscdev);
+       kfifo_free(&lpc_snoop->chan[channel].fifo);
+ }