Revision 9c1c2b35f1d94de8325344c2777d7ee67492db3b authored by Jeff Layton on 03 April 2019, 17:16:01 UTC, committed by Ilya Dryomov on 21 January 2020, 18:02:37 UTC
Currently, we just assume that it will stick around by virtue of the submitter's reference, but later patches will allow the syscall to return early and we can't rely on that reference at that point. While I'm not aware of any reports of it, Xiubo pointed out that this may fix a use-after-free. If the wait for a reply times out or is canceled via signal, and then the reply comes in after the syscall returns, the client can end up trying to access r_parent without a reference. Take an extra reference to the inode when setting r_parent and release it when releasing the request. Cc: stable@vger.kernel.org Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: "Yan, Zheng" <zyan@redhat.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
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timer.c
/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2008 Maxime Bizon <mbizon@freebox.fr>
*/
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/export.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/clk.h>
#include <bcm63xx_cpu.h>
#include <bcm63xx_io.h>
#include <bcm63xx_timer.h>
#include <bcm63xx_regs.h>
static DEFINE_RAW_SPINLOCK(timer_reg_lock);
static DEFINE_RAW_SPINLOCK(timer_data_lock);
static struct clk *periph_clk;
static struct timer_data {
void (*cb)(void *);
void *data;
} timer_data[BCM63XX_TIMER_COUNT];
static irqreturn_t timer_interrupt(int irq, void *dev_id)
{
u32 stat;
int i;
raw_spin_lock(&timer_reg_lock);
stat = bcm_timer_readl(TIMER_IRQSTAT_REG);
bcm_timer_writel(stat, TIMER_IRQSTAT_REG);
raw_spin_unlock(&timer_reg_lock);
for (i = 0; i < BCM63XX_TIMER_COUNT; i++) {
if (!(stat & TIMER_IRQSTAT_TIMER_CAUSE(i)))
continue;
raw_spin_lock(&timer_data_lock);
if (!timer_data[i].cb) {
raw_spin_unlock(&timer_data_lock);
continue;
}
timer_data[i].cb(timer_data[i].data);
raw_spin_unlock(&timer_data_lock);
}
return IRQ_HANDLED;
}
int bcm63xx_timer_enable(int id)
{
u32 reg;
unsigned long flags;
if (id >= BCM63XX_TIMER_COUNT)
return -EINVAL;
raw_spin_lock_irqsave(&timer_reg_lock, flags);
reg = bcm_timer_readl(TIMER_CTLx_REG(id));
reg |= TIMER_CTL_ENABLE_MASK;
bcm_timer_writel(reg, TIMER_CTLx_REG(id));
reg = bcm_timer_readl(TIMER_IRQSTAT_REG);
reg |= TIMER_IRQSTAT_TIMER_IR_EN(id);
bcm_timer_writel(reg, TIMER_IRQSTAT_REG);
raw_spin_unlock_irqrestore(&timer_reg_lock, flags);
return 0;
}
EXPORT_SYMBOL(bcm63xx_timer_enable);
int bcm63xx_timer_disable(int id)
{
u32 reg;
unsigned long flags;
if (id >= BCM63XX_TIMER_COUNT)
return -EINVAL;
raw_spin_lock_irqsave(&timer_reg_lock, flags);
reg = bcm_timer_readl(TIMER_CTLx_REG(id));
reg &= ~TIMER_CTL_ENABLE_MASK;
bcm_timer_writel(reg, TIMER_CTLx_REG(id));
reg = bcm_timer_readl(TIMER_IRQSTAT_REG);
reg &= ~TIMER_IRQSTAT_TIMER_IR_EN(id);
bcm_timer_writel(reg, TIMER_IRQSTAT_REG);
raw_spin_unlock_irqrestore(&timer_reg_lock, flags);
return 0;
}
EXPORT_SYMBOL(bcm63xx_timer_disable);
int bcm63xx_timer_register(int id, void (*callback)(void *data), void *data)
{
unsigned long flags;
int ret;
if (id >= BCM63XX_TIMER_COUNT || !callback)
return -EINVAL;
ret = 0;
raw_spin_lock_irqsave(&timer_data_lock, flags);
if (timer_data[id].cb) {
ret = -EBUSY;
goto out;
}
timer_data[id].cb = callback;
timer_data[id].data = data;
out:
raw_spin_unlock_irqrestore(&timer_data_lock, flags);
return ret;
}
EXPORT_SYMBOL(bcm63xx_timer_register);
void bcm63xx_timer_unregister(int id)
{
unsigned long flags;
if (id >= BCM63XX_TIMER_COUNT)
return;
raw_spin_lock_irqsave(&timer_data_lock, flags);
timer_data[id].cb = NULL;
raw_spin_unlock_irqrestore(&timer_data_lock, flags);
}
EXPORT_SYMBOL(bcm63xx_timer_unregister);
unsigned int bcm63xx_timer_countdown(unsigned int countdown_us)
{
return (clk_get_rate(periph_clk) / (1000 * 1000)) * countdown_us;
}
EXPORT_SYMBOL(bcm63xx_timer_countdown);
int bcm63xx_timer_set(int id, int monotonic, unsigned int countdown_us)
{
u32 reg, countdown;
unsigned long flags;
if (id >= BCM63XX_TIMER_COUNT)
return -EINVAL;
countdown = bcm63xx_timer_countdown(countdown_us);
if (countdown & ~TIMER_CTL_COUNTDOWN_MASK)
return -EINVAL;
raw_spin_lock_irqsave(&timer_reg_lock, flags);
reg = bcm_timer_readl(TIMER_CTLx_REG(id));
if (monotonic)
reg &= ~TIMER_CTL_MONOTONIC_MASK;
else
reg |= TIMER_CTL_MONOTONIC_MASK;
reg &= ~TIMER_CTL_COUNTDOWN_MASK;
reg |= countdown;
bcm_timer_writel(reg, TIMER_CTLx_REG(id));
raw_spin_unlock_irqrestore(&timer_reg_lock, flags);
return 0;
}
EXPORT_SYMBOL(bcm63xx_timer_set);
int bcm63xx_timer_init(void)
{
int ret, irq;
u32 reg;
reg = bcm_timer_readl(TIMER_IRQSTAT_REG);
reg &= ~TIMER_IRQSTAT_TIMER0_IR_EN;
reg &= ~TIMER_IRQSTAT_TIMER1_IR_EN;
reg &= ~TIMER_IRQSTAT_TIMER2_IR_EN;
bcm_timer_writel(reg, TIMER_IRQSTAT_REG);
periph_clk = clk_get(NULL, "periph");
if (IS_ERR(periph_clk))
return -ENODEV;
irq = bcm63xx_get_irq_number(IRQ_TIMER);
ret = request_irq(irq, timer_interrupt, 0, "bcm63xx_timer", NULL);
if (ret) {
pr_err("%s: failed to register irq\n", __func__);
return ret;
}
return 0;
}
arch_initcall(bcm63xx_timer_init);
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