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From:   Frank Zago <frank@zago.net>
To:     Jonathan Cameron <jic23@kernel.org>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Alexandru Ardelean <alexandru.ardelean@analog.com>,
        frank zago <frank@zago.net>, linux-iio@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH 2/2] iio: light: tcs3472: do not free unallocated IRQ
Date:   Mon, 26 Apr 2021 21:20:17 -0500
Message-Id: <20210427022017.19314-2-frank@zago.net>
In-Reply-To: <20210427022017.19314-1-frank@zago.net>
References: <20210427022017.19314-1-frank@zago.net>
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From: frank zago <frank@zago.net>

Allocating an IRQ is conditional to the IRQ existence, but freeing it
was not. If no IRQ was allocate, the driver would still try to free
IRQ 0. Add the missing checks.

This fixes the following trace when the driver is removed:

[  100.667788] Trying to free already-free IRQ 0
[  100.667793] WARNING: CPU: 0 PID: 2315 at kernel/irq/manage.c:1826 free_irq+0x1fd/0x370
[  100.667804] Modules linked in: tcs3472(-) industrialio_triggered_buffer kfifo_buf industrialio ch341_buses binfmt_misc snd_hda_codec_realtek snd_hda_codec_generic ledtrig_audio snd_hda_codec_hdmi snd_hda_intel snd_intel_dspcfg snd_hda_codec snd_hwdep snd_hda_core wmi_bmof snd_pcm snd_seq rapl input_leds snd_timer snd_seq_device snd k10temp ccp soundcore wmi mac_hid sch_fq_codel parport_pc ppdev lp parport ip_tables x_tables autofs4 dm_crypt hid_generic usbhid hid radeon i2c_algo_bit drm_ttm_helper ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops cec rc_core drm crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel crypto_simd r8169 cryptd ahci i2c_piix4 xhci_pci realtek libahci xhci_pci_renesas gpio_amdpt gpio_generic
[  100.667874] CPU: 0 PID: 2315 Comm: rmmod Not tainted 5.12.0+ #29
[  100.667878] ...
[  100.667881] RIP: 0010:free_irq+0x1fd/0x370
[  100.667887] Code: e8 c8 d8 1b 00 48 83 c4 10 4c 89 f8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 8b 75 d0 48 c7 c7 40 8b 36 93 4c 89 4d c8 e8 d1 2c a2 00 <0f> 0b 4c 8b 4d c8 4c 89 f7 4c 89 ce e8 72 c7 a8 00 49 8b 47 40 48
[  100.667891] RSP: 0018:ffff9f44813b7d88 EFLAGS: 00010082
[  100.667895] RAX: 0000000000000000 RBX: ffff8e50caf47800 RCX: ffff8e53cea185c8
[  100.667897] RDX: 00000000ffffffd8 RSI: 0000000000000027 RDI: ffff8e53cea185c0
[  100.667900] RBP: ffff9f44813b7dc0 R08: 0000000000000000 R09: ffff9f44813b7b50
[  100.667902] R10: ffff9f44813b7b48 R11: ffffffff93b53848 R12: ffff8e50c0125080
[  100.667903] R13: ffff8e50c0136f60 R14: ffff8e50c0136ea4 R15: ffff8e50c0136e00
[  100.667906] FS:  00007fa28b899540(0000) GS:ffff8e53cea00000(0000) knlGS:0000000000000000
[  100.667909] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  100.667911] CR2: 0000561851777818 CR3: 000000010633a000 CR4: 00000000003506f0
[  100.667914] Call Trace:
[  100.667920]  tcs3472_remove+0x3a/0x90 [tcs3472]
[  100.667927]  i2c_device_remove+0x2b/0xa0
[  100.667934]  __device_release_driver+0x181/0x240
[  100.667940]  driver_detach+0xd5/0x120
[  100.667944]  bus_remove_driver+0x5c/0xe0
[  100.667947]  driver_unregister+0x31/0x50
[  100.667951]  i2c_del_driver+0x46/0x70
[  100.667955]  tcs3472_driver_exit+0x10/0x5dd [tcs3472]
[  100.667960]  __do_sys_delete_module.constprop.0+0x183/0x290
[  100.667965]  ? exit_to_user_mode_prepare+0x37/0x1c0
[  100.667971]  __x64_sys_delete_module+0x12/0x20
[  100.667974]  do_syscall_64+0x40/0xb0
[  100.667981]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[  100.667985] RIP: 0033:0x7fa28b9dbceb
[  100.667989] Code: 73 01 c3 48 8b 0d 7d 91 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 b0 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 4d 91 0c 00 f7 d8 64 89 01 48
[  100.667992] RSP: 002b:00007ffe02ea7068 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0
[  100.667995] RAX: ffffffffffffffda RBX: 000056185176d750 RCX: 00007fa28b9dbceb
[  100.667997] RDX: 000000000000000a RSI: 0000000000000800 RDI: 000056185176d7b8
[  100.667999] RBP: 00007ffe02ea70c8 R08: 0000000000000000 R09: 0000000000000000
[  100.668001] R10: 00007fa28ba56ac0 R11: 0000000000000206 R12: 00007ffe02ea72a0
[  100.668003] R13: 00007ffe02ea8807 R14: 000056185176d2a0 R15: 000056185176d750
[  100.668007] ---[ end trace b21b0811931d933c ]---

Signed-off-by: frank zago <frank@zago.net>
---
 drivers/iio/light/tcs3472.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/light/tcs3472.c b/drivers/iio/light/tcs3472.c
index a0dc447aeb68..b41068492338 100644
--- a/drivers/iio/light/tcs3472.c
+++ b/drivers/iio/light/tcs3472.c
@@ -531,7 +531,8 @@ static int tcs3472_probe(struct i2c_client *client,
 	return 0;
 
 free_irq:
-	free_irq(client->irq, indio_dev);
+	if (client->irq)
+		free_irq(client->irq, indio_dev);
 buffer_cleanup:
 	iio_triggered_buffer_cleanup(indio_dev);
 	return ret;
@@ -559,7 +560,8 @@ static int tcs3472_remove(struct i2c_client *client)
 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
 
 	iio_device_unregister(indio_dev);
-	free_irq(client->irq, indio_dev);
+	if (client->irq)
+		free_irq(client->irq, indio_dev);
 	iio_triggered_buffer_cleanup(indio_dev);
 	tcs3472_powerdown(iio_priv(indio_dev));
 
-- 
2.27.0