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To:     "David S. Miller" <davem@davemloft.net>,
        Geert Uytterhoeven <geert@linux-m68k.org>
Cc:     "Michael Schmitz" <schmitzmic@gmail.com>,
        "Bartlomiej Zolnierkiewicz" <b.zolnierkie@samsung.com>,
        linux-m68k@lists.linux-m68k.org, linux-ide@vger.kernel.org,
        linux-kernel@vger.kernel.org
Message-Id: <df121aff561c73f3ff7d83f906942ed0d954d737.1600997998.git.fthain@telegraphics.com.au>
From:   Finn Thain <fthain@telegraphics.com.au>
Subject: [PATCH] ide/falconide: Fix module unload
Date:   Fri, 25 Sep 2020 11:39:58 +1000
Precedence: bulk

Unloading the falconide module results in a crash:

Unable to handle kernel NULL pointer dereference at virtual address 00000000
Oops: 00000000
Modules linked in: falconide(-)
PC: [<002930b2>] ide_host_remove+0x2e/0x1d2
SR: 2000  SP: 00b49e28  a2: 009b0f90
d0: 00000000    d1: 009b0f90    d2: 00000000    d3: 00b48000
d4: 003cef32    d5: 00299188    a0: 0086d000    a1: 0086d000
Process rmmod (pid: 322, task=009b0f90)
Frame format=7 eff addr=00000000 ssw=0505 faddr=00000000
wb 1 stat/addr/data: 0000 00000000 00000000
wb 2 stat/addr/data: 0000 00000000 00000000
wb 3 stat/addr/data: 0000 00000000 00018da9
push data: 00000000 00000000 00000000 00000000
Stack from 00b49e90:
        004c456a 0027f176 0027cb0a 0027cb9e 00000000 0086d00a 2187d3f0 0027f0e0
        00b49ebc 2187d1f6 00000000 00b49ec8 002811e8 0086d000 00b49ef0 0028024c
        0086d00a 002800d6 00279a1a 00000001 00000001 0086d00a 2187d3f0 00279a58
        00b49f1c 002802e0 0086d00a 2187d3f0 004c456a 0086d00a ef96af74 00000000
        2187d3f0 002805d2 800de064 00b49f44 0027f088 2187d3f0 00ac1cf4 2187d3f0
        004c43be 2187d3f0 00000000 2187d3f0 800b66a8 00b49f5c 00280776 2187d3f0
Call Trace: [<0027f176>] __device_driver_unlock+0x0/0x48
 [<0027cb0a>] device_links_busy+0x0/0x94
 [<0027cb9e>] device_links_unbind_consumers+0x0/0x130
 [<0027f0e0>] __device_driver_lock+0x0/0x5a
 [<2187d1f6>] falconide_remove+0x12/0x18 [falconide]
 [<002811e8>] platform_drv_remove+0x1c/0x28
 [<0028024c>] device_release_driver_internal+0x176/0x17c
 [<002800d6>] device_release_driver_internal+0x0/0x17c
 [<00279a1a>] get_device+0x0/0x22
 [<00279a58>] put_device+0x0/0x18
 [<002802e0>] driver_detach+0x56/0x82
 [<002805d2>] driver_remove_file+0x0/0x24
 [<0027f088>] bus_remove_driver+0x4c/0xa4
 [<00280776>] driver_unregister+0x28/0x5a
 [<00281a00>] platform_driver_unregister+0x12/0x18
 [<2187d2a0>] ide_falcon_driver_exit+0x10/0x16 [falconide]
 [<000764f0>] sys_delete_module+0x110/0x1f2
 [<000e83ea>] sys_rename+0x1a/0x1e
 [<00002e0c>] syscall+0x8/0xc
 [<00188004>] ext4_multi_mount_protect+0x35a/0x3ce
Code: 0029 9188 4bf9 0027 aa1c 283c 003c ef32 <265c> 4a8b 6700 00b8 2043 2028 000c 0280 00ff ff00 6600 0176 40c0 7202 b2b9 004c
Disabling lock debugging due to kernel taint

This happens because the driver_data pointer is uninitialized.
Add the missing platform_set_drvdata() call. For clarity, use the
matching platform_get_drvdata() as well.

Cc: Michael Schmitz <schmitzmic@gmail.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: linux-m68k@lists.linux-m68k.org
Fixes: 5ed0794cde593 ("m68k/atari: Convert Falcon IDE drivers to platform drivers")
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
---
This patch was tested using Aranym.
---
 drivers/ide/falconide.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/ide/falconide.c b/drivers/ide/falconide.c
index dbeb2605e5f6e..607c44bc50f1b 100644
--- a/drivers/ide/falconide.c
+++ b/drivers/ide/falconide.c
@@ -166,6 +166,7 @@ static int __init falconide_init(struct platform_device *pdev)
 	if (rc)
 		goto err_free;
 
+	platform_set_drvdata(pdev, host);
 	return 0;
 err_free:
 	ide_host_free(host);
@@ -176,7 +177,7 @@ static int __init falconide_init(struct platform_device *pdev)
 
 static int falconide_remove(struct platform_device *pdev)
 {
-	struct ide_host *host = dev_get_drvdata(&pdev->dev);
+	struct ide_host *host = platform_get_drvdata(pdev);
 
 	ide_host_remove(host);
 
-- 
2.26.2