Revision ebff65473f56e6c30de928fd6a4f1ce5ae36e8c5 authored by Shawn Guo on 02 December 2013, 05:26:50 UTC, committed by Mark Brown on 02 December 2013, 11:50:53 UTC
Since devm_card_release() expects parameter 'res' to be a pointer to
struct snd_soc_card, devm_snd_soc_register_card() should really pass
such a pointer rather than the one to struct device.

This bug causes the kernel Oops below with imx-sgtl500 driver when we
remove the module.  It happens because with 'card' pointing to the wrong
structure, card->num_rtd becomes 0 in function soc_remove_dai_links().
Consequently, soc_remove_link_components() and in turn
soc_cleanup_codec[platform]_debugfs() will not be called on card
removal.  It results in that debugfs_card_root is being removed while
its child entries debugfs_codec_root and debugfs_platform_root are still
there, and thus the kernel Oops.

Fix the bug by correcting the parameter 'res' to be the pointer to
struct snd_soc_card.

$ lsmod
Module                  Size  Used by
snd_soc_imx_sgtl5000     3506  0
snd_soc_sgtl5000       13677  2
snd_soc_imx_audmux      5324  1 snd_soc_imx_sgtl5000
snd_soc_fsl_ssi         8139  2
imx_pcm_dma             1380  1 snd_soc_fsl_ssi
$ rmmod snd_soc_imx_sgtl5000
Unable to handle kernel paging request at virtual address e594025c
pgd = be134000
[e594025c] *pgd=00000000
Internal error: Oops: 5 [#1] SMP ARM
Modules linked in: snd_soc_imx_sgtl5000(-) snd_soc_sgtl5000 snd_soc_imx_audmux snd_soc_fsl_ssi imx_pcm_dma
CPU: 0 PID: 1793 Comm: rmmod Not tainted 3.13.0-rc1 #1570
task: bee28900 ti: bfbec000 task.ti: bfbec000
PC is at debugfs_remove_recursive+0x28/0x154
LR is at snd_soc_unregister_card+0xa0/0xcc
pc : [<80252b38>]    lr : [<80496ac4>]    psr: a0000013
sp : bfbede00  ip : bfbede28  fp : bfbede24
r10: 803281d4  r9 : bfbec000  r8 : 803271ac
r7 : bef54440  r6 : 00000004  r5 : bf9a4010  r4 : bf9a4010
r3 : e5940224  r2 : 00000000  r1 : bef54450  r0 : 803271ac
Flags: NzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
Control: 10c53c7d  Table: 4e13404a  DAC: 00000015
Process rmmod (pid: 1793, stack limit = 0xbfbec240)
Stack: (0xbfbede00 to 0xbfbee000)
de00: 00000000 bf9a4010 bf9a4010 00000004 bef54440 bec89000 bfbede44 bfbede28
de20: 80496ac4 80252b1c 804a4b60 bfbede60 bf9a4010 00000004 bfbede54 bfbede48
de40: 804a4b74 80496a30 bfbede94 bfbede58 80328728 804a4b6c bfbede94 a0000013
de60: bf1b5800 bef54440 00000002 bf9a4010 7f0169f8 bf9a4044 00000081 8000e9c4
de80: bfbec000 00000000 bfbedeac bfbede98 80328cb0 80328618 7f016000 bf9a4010
dea0: bfbedec4 bfbedeb0 8032561c 80328c84 bf9a4010 7f0169f8 bfbedee4 bfbedec8
dec0: 80325e84 803255a8 bee28900 7f0169f8 00000000 78208d30 bfbedefc bfbedee8
dee0: 80325410 80325dd4 beca8100 7f0169f8 bfbedf14 bfbedf00 803264f8 803253c8
df00: 7f01635c 7f016a3c bfbedf24 bfbedf18 80327098 803264d4 bfbedf34 bfbedf28
df20: 7f016370 80327090 bfbedfa4 bfbedf38 80085ef0 7f016368 bfbedf54 5f646e73
df40: 5f636f73 5f786d69 6c746773 30303035 00000000 78208008 bfbedf84 bfbedf68
df60: 800613b0 80061194 fffffffe 78208d00 7efc2f07 00000081 7f016a3c 00000800
df80: bfbedf84 00000000 00000000 fffffffe 78208d00 7efc2f07 00000000 bfbedfa8
dfa0: 8000e800 80085dcc fffffffe 78208d00 78208d30 00000800 a8c82400 a8c82400
dfc0: fffffffe 78208d00 7efc2f07 00000081 00000002 00000000 78208008 00000800
dfe0: 7efc2e1c 7efc2ba8 76f5ca47 76edec7c 80000010 78208d30 00000000 00000000
Backtrace:
[<80252b10>] (debugfs_remove_recursive+0x0/0x154) from [<80496ac4>] (snd_soc_unregister_card+0xa0/0xcc)
 r8:bec89000 r7:bef54440 r6:00000004 r5:bf9a4010 r4:bf9a4010
r3:00000000
[<80496a24>] (snd_soc_unregister_card+0x0/0xcc) from [<804a4b74>] (devm_card_release+0x14/0x18)
 r6:00000004 r5:bf9a4010 r4:bfbede60 r3:804a4b60
[<804a4b60>] (devm_card_release+0x0/0x18) from [<80328728>] (release_nodes+0x11c/0x1dc)
[<8032860c>] (release_nodes+0x0/0x1dc) from [<80328cb0>] (devres_release_all+0x38/0x54)
[<80328c78>] (devres_release_all+0x0/0x54) from [<8032561c>] (__device_release_driver+0x80/0xd4)
 r4:bf9a4010 r3:7f016000
[<8032559c>] (__device_release_driver+0x0/0xd4) from [<80325e84>] (driver_detach+0xbc/0xc0)
 r5:7f0169f8 r4:bf9a4010
[<80325dc8>] (driver_detach+0x0/0xc0) from [<80325410>] (bus_remove_driver+0x54/0x98)
 r6:78208d30 r5:00000000 r4:7f0169f8 r3:bee28900
[<803253bc>] (bus_remove_driver+0x0/0x98) from [<803264f8>] (driver_unregister+0x30/0x50)
 r4:7f0169f8 r3:beca8100
[<803264c8>] (driver_unregister+0x0/0x50) from [<80327098>] (platform_driver_unregister+0x14/0x18)
 r4:7f016a3c r3:7f01635c
[<80327084>] (platform_driver_unregister+0x0/0x18) from [<7f016370>] (imx_sgtl5000_driver_exit+0x14/0x1c [snd_soc_imx_sgtl5000])
[<7f01635c>] (imx_sgtl5000_driver_exit+0x0/0x1c [snd_soc_imx_sgtl5000]) from [<80085ef0>] (SyS_delete_module+0x130/0x18c)
[<80085dc0>] (SyS_delete_module+0x0/0x18c) from [<8000e800>] (ret_fast_syscall+0x0/0x48)
 r6:7efc2f07 r5:78208d00 r4:fffffffe
Code: 889da9f8 e5983020 e3530000 089da9f8 (e5933038)
---[ end trace 825e7e125251a225 ]---

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>
1 parent 8f1ec93
Raw File
inode.c
/*
 * Copyright (C) 2012 Red Hat, Inc.
 * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/efi.h>
#include <linux/fs.h>
#include <linux/ctype.h>
#include <linux/slab.h>

#include "internal.h"

struct inode *efivarfs_get_inode(struct super_block *sb,
				const struct inode *dir, int mode, dev_t dev)
{
	struct inode *inode = new_inode(sb);

	if (inode) {
		inode->i_ino = get_next_ino();
		inode->i_mode = mode;
		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
		switch (mode & S_IFMT) {
		case S_IFREG:
			inode->i_fop = &efivarfs_file_operations;
			break;
		case S_IFDIR:
			inode->i_op = &efivarfs_dir_inode_operations;
			inode->i_fop = &simple_dir_operations;
			inc_nlink(inode);
			break;
		}
	}
	return inode;
}

/*
 * Return true if 'str' is a valid efivarfs filename of the form,
 *
 *	VariableName-12345678-1234-1234-1234-1234567891bc
 */
bool efivarfs_valid_name(const char *str, int len)
{
	static const char dashes[EFI_VARIABLE_GUID_LEN] = {
		[8] = 1, [13] = 1, [18] = 1, [23] = 1
	};
	const char *s = str + len - EFI_VARIABLE_GUID_LEN;
	int i;

	/*
	 * We need a GUID, plus at least one letter for the variable name,
	 * plus the '-' separator
	 */
	if (len < EFI_VARIABLE_GUID_LEN + 2)
		return false;

	/* GUID must be preceded by a '-' */
	if (*(s - 1) != '-')
		return false;

	/*
	 * Validate that 's' is of the correct format, e.g.
	 *
	 *	12345678-1234-1234-1234-123456789abc
	 */
	for (i = 0; i < EFI_VARIABLE_GUID_LEN; i++) {
		if (dashes[i]) {
			if (*s++ != '-')
				return false;
		} else {
			if (!isxdigit(*s++))
				return false;
		}
	}

	return true;
}

static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
{
	guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
	guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
	guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
	guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
	guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
	guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
	guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
	guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
	guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
	guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
	guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
	guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
	guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
	guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
	guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
	guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
}

static int efivarfs_create(struct inode *dir, struct dentry *dentry,
			  umode_t mode, bool excl)
{
	struct inode *inode;
	struct efivar_entry *var;
	int namelen, i = 0, err = 0;

	if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
		return -EINVAL;

	inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
	if (!inode)
		return -ENOMEM;

	var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
	if (!var) {
		err = -ENOMEM;
		goto out;
	}

	/* length of the variable name itself: remove GUID and separator */
	namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1;

	efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
			&var->var.VendorGuid);

	for (i = 0; i < namelen; i++)
		var->var.VariableName[i] = dentry->d_name.name[i];

	var->var.VariableName[i] = '\0';

	inode->i_private = var;

	efivar_entry_add(var, &efivarfs_list);
	d_instantiate(dentry, inode);
	dget(dentry);
out:
	if (err) {
		kfree(var);
		iput(inode);
	}
	return err;
}

static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
{
	struct efivar_entry *var = dentry->d_inode->i_private;

	if (efivar_entry_delete(var))
		return -EINVAL;

	drop_nlink(dentry->d_inode);
	dput(dentry);
	return 0;
};

const struct inode_operations efivarfs_dir_inode_operations = {
	.lookup = simple_lookup,
	.unlink = efivarfs_unlink,
	.create = efivarfs_create,
};
back to top