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Revision dec24b3b339487e58ce2da2875e9ee0316cc7e70 authored by Kees Cook on 20 June 2023, 19:42:38 UTC, committed by Paolo Abeni on 22 June 2023, 09:27:47 UTC 
net: wwan: iosm: Convert single instance struct member to flexible array
 
struct mux_adth actually ends with multiple struct mux_adth_dg members.
This is seen both in the comments about the member:

/**
 * struct mux_adth - Structure of the Aggregated Datagram Table Header.
 ...
 * @dg:		datagramm table with variable length
 */

and in the preparation for populating it:

                        adth_dg_size = offsetof(struct mux_adth, dg) +
                                        ul_adb->dg_count[i] * sizeof(*dg);
			...
                        adth_dg_size -= offsetof(struct mux_adth, dg);
                        memcpy(&adth->dg, ul_adb->dg[i], adth_dg_size);

This was reported as a run-time false positive warning:

memcpy: detected field-spanning write (size 16) of single field "&adth->dg" at drivers/net/wwan/iosm/iosm_ipc_mux_codec.c:852 (size 8)

Adjust the struct mux_adth definition and associated sizeof() math; no binary
output differences are observed in the resulting object file.

Reported-by: Florian Klink <flokli@flokli.de>
Closes: https://lore.kernel.org/lkml/dbfa25f5-64c8-5574-4f5d-0151ba95d232@gmail.com/
Fixes: 1f52d7b62285 ("net: wwan: iosm: Enable M.2 7360 WWAN card support")
Cc: M Chetan Kumar <m.chetan.kumar@intel.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Intel Corporation <linuxwwan@intel.com>
Cc: Loic Poulain <loic.poulain@linaro.org>
Cc: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20230620194234.never.023-kees@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
1 parent 2174a08
Raw File
once.c 
// SPDX-License-Identifier: GPL-2.0
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/once.h>
#include <linux/random.h>
#include <linux/module.h>

struct once_work {
	struct work_struct work;
	struct static_key_true *key;
	struct module *module;
};

static void once_deferred(struct work_struct *w)
{
	struct once_work *work;

	work = container_of(w, struct once_work, work);
	BUG_ON(!static_key_enabled(work->key));
	static_branch_disable(work->key);
	module_put(work->module);
	kfree(work);
}

static void once_disable_jump(struct static_key_true *key, struct module *mod)
{
	struct once_work *w;

	w = kmalloc(sizeof(*w), GFP_ATOMIC);
	if (!w)
		return;

	INIT_WORK(&w->work, once_deferred);
	w->key = key;
	w->module = mod;
	__module_get(mod);
	schedule_work(&w->work);
}

static DEFINE_SPINLOCK(once_lock);

bool __do_once_start(bool *done, unsigned long *flags)
	__acquires(once_lock)
{
	spin_lock_irqsave(&once_lock, *flags);
	if (*done) {
		spin_unlock_irqrestore(&once_lock, *flags);
		/* Keep sparse happy by restoring an even lock count on
		 * this lock. In case we return here, we don't call into
		 * __do_once_done but return early in the DO_ONCE() macro.
		 */
		__acquire(once_lock);
		return false;
	}

	return true;
}
EXPORT_SYMBOL(__do_once_start);

void __do_once_done(bool *done, struct static_key_true *once_key,
		    unsigned long *flags, struct module *mod)
	__releases(once_lock)
{
	*done = true;
	spin_unlock_irqrestore(&once_lock, *flags);
	once_disable_jump(once_key, mod);
}
EXPORT_SYMBOL(__do_once_done);

static DEFINE_MUTEX(once_mutex);

bool __do_once_sleepable_start(bool *done)
	__acquires(once_mutex)
{
	mutex_lock(&once_mutex);
	if (*done) {
		mutex_unlock(&once_mutex);
		/* Keep sparse happy by restoring an even lock count on
		 * this mutex. In case we return here, we don't call into
		 * __do_once_done but return early in the DO_ONCE_SLEEPABLE() macro.
		 */
		__acquire(once_mutex);
		return false;
	}

	return true;
}
EXPORT_SYMBOL(__do_once_sleepable_start);

void __do_once_sleepable_done(bool *done, struct static_key_true *once_key,
			 struct module *mod)
	__releases(once_mutex)
{
	*done = true;
	mutex_unlock(&once_mutex);
	once_disable_jump(once_key, mod);
}
EXPORT_SYMBOL(__do_once_sleepable_done);
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