From: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
I wanted to disable a node via OF_DYNAMIC by setting its status to disabled.
This code is the minimal testcase, the same happens in a more complex scenario.
There is something wrong with freeing resources. Is my module wrong? Or is it a
bug? Crashlog without CONFIG_I2C_CHARDEV, slightly shortened:
[ 5.127314] of/notify UPDATE_PROPERTY /i2c@e60b0000:status
[ 5.132814] i2c-sh_mobile e60b0000.i2c: pm_clk_notify() 2
[ 5.138504] bus: 'platform': remove device e60b0000.i2c
[ 5.143762] i2c-sh_mobile e60b0000.i2c: pm_clk_notify() 6
[ 5.149231] device: '7-0068': device_unregister
[ 5.153982] bus: 'i2c': remove device 7-0068
[ 5.158679] device: 'regulator.2': device_unregister
[ 5.165827] i2c 7-0068: uevent
[ 5.168997] i2c i2c-7: adapter [e60b0000.i2c] unregistered
[ 5.174462] device: 'i2c-7': device_unregister
[ 5.179057] bus: 'i2c': remove device i2c-7
[ 5.183570] platform e60b0000.i2c: pm_clk_notify() 7
[ 5.188595] platform e60b0000.i2c: Runtime PM disabled, clock forced off.
[ 5.195368] platform e60b0000.i2c: pm_clk_notify() 3
[ 5.200426] Unable to handle kernel NULL pointer dereference at virtual address 00000018
[ 5.208474] pgd = c0004000
[ 5.211164] [00000018] *pgd=00000000
[ 5.214745] Internal error: Oops: 5 [#1] ARM
[ 5.218995] CPU: 0 PID: 1 Comm: swapper Tainted: G W 4.0.0-rc4-00009-gcb55587ebc4047 #90
[ 5.228148] Hardware name: Generic R8A7790 (Flattened Device Tree)
[ 5.234288] task: ee84d340 ti: ee84e000 task.ti: ee84e000
[ 5.239656] PC is at release_resource+0x20/0x68
[ 5.244171] LR is at _raw_write_lock+0x3c/0x44
[ 5.248591] pc : [<c002417c>] lr : [<c025f0e0>] psr: a0000113
[ 5.248591] sp : ee84fcd8 ip : ee84fcb0 fp : ee84fcec
[ 5.259989] r10: 00000000 r9 : c03de2c0 r8 : c03d5694
[ 5.265180] r7 : ee84fdf4 r6 : 0000001c r5 : 00000000 r4 : ee8efd00
[ 5.271664] r3 : 00000000 r2 : 00000018 r1 : 00000009 r0 : c03c7cd8
[ 5.278149] Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel
[ 5.285410] Control: 10c5347d Table: 40004059 DAC: 00000015
[ 5.291117] Process swapper (pid: 1, stack limit = 0xee84e208)
[ 5.296911] Stack: (0xee84fcd8 to 0xee850000)
[ 5.301243] fcc0: 00000000 ee8f3e00
[ 5.309375] fce0: ee84fd0c ee84fcf0 c01604fc c0024168 c03d39a0 ee8f3e00 00000000 00000005
[ 5.317507] fd00: ee84fd24 ee84fd10 c016054c c0160494 c03d39a0 ee8f3e10 ee84fd3c ee84fd28
[ 5.325639] fd20: c01aad54 c0160544 ee8f3e34 ee8f3e00 ee84fd64 ee84fd40 c01ab3f8 c01aad08
...
[ 5.512643] Backtrace:
[ 5.515097] [<c002415c>] (release_resource) from [<c01604fc>] (platform_device_del+0x74/0x84)
[ 5.523561] r4:ee8f3e00 r3:00000000
[ 5.527145] [<c0160488>] (platform_device_del) from [<c016054c>] (platform_device_unregister+0x14/0x20)
[ 5.536469] r6:00000005 r5:00000000 r4:ee8f3e00 r3:c03d39a0
[ 5.542152] [<c0160538>] (platform_device_unregister) from [<c01aad54>] (of_platform_device_destroy+0x58/0xa8)
[ 5.552080] r4:ee8f3e10 r3:c03d39a0
[ 5.555667] [<c01aacfc>] (of_platform_device_destroy) from [<c01ab3f8>] (of_platform_notify+0xcc/0xe8)
[ 5.564905] r4:ee8f3e00 r3:ee8f3e34
[ 5.568493] [<c01ab32c>] (of_platform_notify) from [<c00389b0>] (notifier_call_chain+0x48/0x70)
[ 5.577128] r6:00000005 r5:00000000 r4:ffffffff
[ 5.581759] [<c0038968>] (notifier_call_chain) from [<c0038c78>] (__blocking_notifier_call_chain+0x4c/0x64)
[ 5.591429] r8:00000005 r7:ee84fdf4 r6:ffffffff r5:c03d7ba4 r4:c03d7b98 r3:ffffffff
[ 5.599192] [<c0038c2c>] (__blocking_notifier_call_chain) from [<c0038cb0>] (blocking_notifier_call_chain+0x20/0x28)
[ 5.609637] r8:c0340d2c r7:c0340d2c r6:ee84fe88 r5:00000005 r4:ee84fdf4
[ 5.616365] [<c0038c90>] (blocking_notifier_call_chain) from [<c01ab868>] (of_reconfig_notify+0x88/0xa8)
[ 5.625788] [<c01ab7e0>] (of_reconfig_notify) from [<c01aba70>] (of_property_notify+0x44/0x4c)
[ 5.634338] r5:ee84fe88 r4:ee940440
[ 5.637925] [<c01aba2c>] (of_property_notify) from [<c01abafc>] (__of_changeset_entry_notify+0x84/0xc4)
[ 5.647263] [<c01aba78>] (__of_changeset_entry_notify) from [<c01ac408>] (of_changeset_apply+0xa4/0xe4)
[ 5.656588] r4:ee940440
[ 5.659126] [<c01ac364>] (of_changeset_apply) from [<c0335744>] (test_init+0x84/0xa8)
[ 5.666900] r6:00000000 r5:c03356c0 r4:eefd18b8
[ 5.671533] [<c03356c0>] (test_init) from [<c0321dd8>] (do_one_initcall+0x108/0x1bc)
[ 5.679220] r4:ee940440
Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
---
drivers/of/Makefile | 2 +-
drivers/of/wsa_testcase.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 49 insertions(+), 1 deletion(-)
create mode 100644 drivers/of/wsa_testcase.c
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index 7563f36c71db34..4ec30a5bab39d5 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -1,4 +1,4 @@
-obj-y = base.o device.o platform.o
+obj-y = base.o device.o platform.o wsa_testcase.o
obj-$(CONFIG_OF_DYNAMIC) += dynamic.o
obj-$(CONFIG_OF_FLATTREE) += fdt.o
obj-$(CONFIG_OF_EARLY_FLATTREE) += fdt_address.o
diff --git a/drivers/of/wsa_testcase.c b/drivers/of/wsa_testcase.c
new file mode 100644
index 00000000000000..b6bffd1acf76ad
--- /dev/null
+++ b/drivers/of/wsa_testcase.c
@@ -0,0 +1,48 @@
+/*
+ * Testcase for disabling nodes via OF_DYNAMIC
+ *
+ * Copyright (C) 2015 by Wolfram Sang, Sang Engineering <wsa@xxxxxxxxxxxxxxxxxxxx>
+ * Copyright (C) 2015 by Renesas Electronics Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; version 2 of the License.
+ */
+
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include "of_private.h"
+
+static __init int test_init(void)
+{
+
+ struct i2c_adapter *adap;
+ struct device_node *np;
+ struct of_changeset chgset;
+ struct property status_chg = { .name = "status", .length = 9, .value = "disabled" };
+ int ret;
+
+ // Use an active adapter here
+ adap = i2c_get_adapter(0);
+ if (!adap)
+ return -EPROBE_DEFER;
+
+ np = adap->dev.of_node;
+
+ i2c_put_adapter(adap);
+
+ of_changeset_init(&chgset);
+ of_changeset_update_property(&chgset, np, &status_chg);
+
+ mutex_lock(&of_mutex);
+ ret = of_changeset_apply(&chgset);
+ mutex_unlock(&of_mutex);
+
+ return ret;
+}
+late_initcall(test_init);
+
+MODULE_AUTHOR("Wolfram Sang <wsa@xxxxxxxxxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
--
2.1.4
--
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