From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- drivers/clocksource/timer-mp-csky.c | 173 ++++++++++++++++++++++++++++++++++++ 1 file changed, 173 insertions(+) create mode 100644 drivers/clocksource/timer-mp-csky.c (limited to 'drivers/clocksource/timer-mp-csky.c') diff --git a/drivers/clocksource/timer-mp-csky.c b/drivers/clocksource/timer-mp-csky.c new file mode 100644 index 000000000..183a99551 --- /dev/null +++ b/drivers/clocksource/timer-mp-csky.c @@ -0,0 +1,173 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. + +#include +#include +#include +#include +#include +#include + +#include "timer-of.h" + +#define PTIM_CCVR "cr<3, 14>" +#define PTIM_CTLR "cr<0, 14>" +#define PTIM_LVR "cr<6, 14>" +#define PTIM_TSR "cr<1, 14>" + +static int csky_mptimer_irq; + +static int csky_mptimer_set_next_event(unsigned long delta, + struct clock_event_device *ce) +{ + mtcr(PTIM_LVR, delta); + + return 0; +} + +static int csky_mptimer_shutdown(struct clock_event_device *ce) +{ + mtcr(PTIM_CTLR, 0); + + return 0; +} + +static int csky_mptimer_oneshot(struct clock_event_device *ce) +{ + mtcr(PTIM_CTLR, 1); + + return 0; +} + +static int csky_mptimer_oneshot_stopped(struct clock_event_device *ce) +{ + mtcr(PTIM_CTLR, 0); + + return 0; +} + +static DEFINE_PER_CPU(struct timer_of, csky_to) = { + .flags = TIMER_OF_CLOCK, + .clkevt = { + .rating = 300, + .features = CLOCK_EVT_FEAT_PERCPU | + CLOCK_EVT_FEAT_ONESHOT, + .set_state_shutdown = csky_mptimer_shutdown, + .set_state_oneshot = csky_mptimer_oneshot, + .set_state_oneshot_stopped = csky_mptimer_oneshot_stopped, + .set_next_event = csky_mptimer_set_next_event, + }, +}; + +static irqreturn_t csky_timer_interrupt(int irq, void *dev) +{ + struct timer_of *to = this_cpu_ptr(&csky_to); + + mtcr(PTIM_TSR, 0); + + to->clkevt.event_handler(&to->clkevt); + + return IRQ_HANDLED; +} + +/* + * clock event for percpu + */ +static int csky_mptimer_starting_cpu(unsigned int cpu) +{ + struct timer_of *to = per_cpu_ptr(&csky_to, cpu); + + to->clkevt.cpumask = cpumask_of(cpu); + + enable_percpu_irq(csky_mptimer_irq, 0); + + clockevents_config_and_register(&to->clkevt, timer_of_rate(to), + 2, ULONG_MAX); + + return 0; +} + +static int csky_mptimer_dying_cpu(unsigned int cpu) +{ + disable_percpu_irq(csky_mptimer_irq); + + return 0; +} + +/* + * clock source + */ +static u64 notrace sched_clock_read(void) +{ + return (u64)mfcr(PTIM_CCVR); +} + +static u64 clksrc_read(struct clocksource *c) +{ + return (u64)mfcr(PTIM_CCVR); +} + +struct clocksource csky_clocksource = { + .name = "csky", + .rating = 400, + .mask = CLOCKSOURCE_MASK(32), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, + .read = clksrc_read, +}; + +static int __init csky_mptimer_init(struct device_node *np) +{ + int ret, cpu, cpu_rollback; + struct timer_of *to = NULL; + + /* + * Csky_mptimer is designed for C-SKY SMP multi-processors and + * every core has it's own private irq and regs for clkevt and + * clksrc. + * + * The regs is accessed by cpu instruction: mfcr/mtcr instead of + * mmio map style. So we needn't mmio-address in dts, but we still + * need to give clk and irq number. + * + * We use private irq for the mptimer and irq number is the same + * for every core. So we use request_percpu_irq() in timer_of_init. + */ + csky_mptimer_irq = irq_of_parse_and_map(np, 0); + if (csky_mptimer_irq <= 0) + return -EINVAL; + + ret = request_percpu_irq(csky_mptimer_irq, csky_timer_interrupt, + "csky_mp_timer", &csky_to); + if (ret) + return -EINVAL; + + for_each_possible_cpu(cpu) { + to = per_cpu_ptr(&csky_to, cpu); + ret = timer_of_init(np, to); + if (ret) + goto rollback; + } + + clocksource_register_hz(&csky_clocksource, timer_of_rate(to)); + sched_clock_register(sched_clock_read, 32, timer_of_rate(to)); + + ret = cpuhp_setup_state(CPUHP_AP_CSKY_TIMER_STARTING, + "clockevents/csky/timer:starting", + csky_mptimer_starting_cpu, + csky_mptimer_dying_cpu); + if (ret) + return -EINVAL; + + return 0; + +rollback: + for_each_possible_cpu(cpu_rollback) { + if (cpu_rollback == cpu) + break; + + to = per_cpu_ptr(&csky_to, cpu_rollback); + timer_of_cleanup(to); + } + return -EINVAL; +} +TIMER_OF_DECLARE(csky_mptimer, "csky,mptimer", csky_mptimer_init); -- cgit v1.3.1