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Revision 7ff57e98fb78ad94edafbdc7435f2d745e9e6bb5 authored by Fabio M. De Francesco on 23 February 2022, 10:02:52 UTC, committed by Jakub Kicinski on 24 February 2022, 17:09:33 UTC 
net/smc: Use a mutex for locking "struct smc_pnettable"
 
smc_pnetid_by_table_ib() uses read_lock() and then it calls smc_pnet_apply_ib()
which, in turn, calls mutex_lock(&smc_ib_devices.mutex).

read_lock() disables preemption. Therefore, the code acquires a mutex while in
atomic context and it leads to a SAC bug.

Fix this bug by replacing the rwlock with a mutex.

Reported-and-tested-by: syzbot+4f322a6d84e991c38775@syzkaller.appspotmail.com
Fixes: 64e28b52c7a6 ("net/smc: add pnet table namespace support")
Confirmed-by: Tony Lu <tonylu@linux.alibaba.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Acked-by: Karsten Graul <kgraul@linux.ibm.com>
Link: https://lore.kernel.org/r/20220223100252.22562-1-fmdefrancesco@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Raw File
of-reconfig-notifier-error-inject.c 
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>

#include "notifier-error-inject.h"

static int priority;
module_param(priority, int, 0);
MODULE_PARM_DESC(priority, "specify OF reconfig notifier priority");

static struct notifier_err_inject reconfig_err_inject = {
	.actions = {
		{ NOTIFIER_ERR_INJECT_ACTION(OF_RECONFIG_ATTACH_NODE) },
		{ NOTIFIER_ERR_INJECT_ACTION(OF_RECONFIG_DETACH_NODE) },
		{ NOTIFIER_ERR_INJECT_ACTION(OF_RECONFIG_ADD_PROPERTY) },
		{ NOTIFIER_ERR_INJECT_ACTION(OF_RECONFIG_REMOVE_PROPERTY) },
		{ NOTIFIER_ERR_INJECT_ACTION(OF_RECONFIG_UPDATE_PROPERTY) },
		{}
	}
};

static struct dentry *dir;

static int err_inject_init(void)
{
	int err;

	dir = notifier_err_inject_init("OF-reconfig",
		notifier_err_inject_dir, &reconfig_err_inject, priority);
	if (IS_ERR(dir))
		return PTR_ERR(dir);

	err = of_reconfig_notifier_register(&reconfig_err_inject.nb);
	if (err)
		debugfs_remove_recursive(dir);

	return err;
}

static void err_inject_exit(void)
{
	of_reconfig_notifier_unregister(&reconfig_err_inject.nb);
	debugfs_remove_recursive(dir);
}

module_init(err_inject_init);
module_exit(err_inject_exit);

MODULE_DESCRIPTION("OF reconfig notifier error injection module");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
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