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 --- net/lapb/lapb_timer.c | 206 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 206 insertions(+) create mode 100644 net/lapb/lapb_timer.c (limited to 'net/lapb/lapb_timer.c') diff --git a/net/lapb/lapb_timer.c b/net/lapb/lapb_timer.c new file mode 100644 index 000000000..9fde6cf20 --- /dev/null +++ b/net/lapb/lapb_timer.c @@ -0,0 +1,206 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * LAPB release 002 + * + * This code REQUIRES 2.1.15 or higher/ NET3.038 + * + * History + * LAPB 001 Jonathan Naylor Started Coding + * LAPB 002 Jonathan Naylor New timer architecture. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static void lapb_t1timer_expiry(struct timer_list *); +static void lapb_t2timer_expiry(struct timer_list *); + +void lapb_start_t1timer(struct lapb_cb *lapb) +{ + timer_delete(&lapb->t1timer); + + lapb->t1timer.function = lapb_t1timer_expiry; + lapb->t1timer.expires = jiffies + lapb->t1; + + lapb->t1timer_running = true; + add_timer(&lapb->t1timer); +} + +void lapb_start_t2timer(struct lapb_cb *lapb) +{ + timer_delete(&lapb->t2timer); + + lapb->t2timer.function = lapb_t2timer_expiry; + lapb->t2timer.expires = jiffies + lapb->t2; + + lapb->t2timer_running = true; + add_timer(&lapb->t2timer); +} + +void lapb_stop_t1timer(struct lapb_cb *lapb) +{ + lapb->t1timer_running = false; + timer_delete(&lapb->t1timer); +} + +void lapb_stop_t2timer(struct lapb_cb *lapb) +{ + lapb->t2timer_running = false; + timer_delete(&lapb->t2timer); +} + +int lapb_t1timer_running(struct lapb_cb *lapb) +{ + return lapb->t1timer_running; +} + +static void lapb_t2timer_expiry(struct timer_list *t) +{ + struct lapb_cb *lapb = timer_container_of(lapb, t, t2timer); + + spin_lock_bh(&lapb->lock); + if (timer_pending(&lapb->t2timer)) /* A new timer has been set up */ + goto out; + if (!lapb->t2timer_running) /* The timer has been stopped */ + goto out; + + if (lapb->condition & LAPB_ACK_PENDING_CONDITION) { + lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; + lapb_timeout_response(lapb); + } + lapb->t2timer_running = false; + +out: + spin_unlock_bh(&lapb->lock); +} + +static void lapb_t1timer_expiry(struct timer_list *t) +{ + struct lapb_cb *lapb = timer_container_of(lapb, t, t1timer); + + spin_lock_bh(&lapb->lock); + if (timer_pending(&lapb->t1timer)) /* A new timer has been set up */ + goto out; + if (!lapb->t1timer_running) /* The timer has been stopped */ + goto out; + + switch (lapb->state) { + + /* + * If we are a DCE, send DM up to N2 times, then switch to + * STATE_1 and send SABM(E). + */ + case LAPB_STATE_0: + if (lapb->mode & LAPB_DCE && + lapb->n2count != lapb->n2) { + lapb->n2count++; + lapb_send_control(lapb, LAPB_DM, LAPB_POLLOFF, LAPB_RESPONSE); + } else { + lapb->state = LAPB_STATE_1; + lapb_establish_data_link(lapb); + } + break; + + /* + * Awaiting connection state, send SABM(E), up to N2 times. + */ + case LAPB_STATE_1: + if (lapb->n2count == lapb->n2) { + lapb_clear_queues(lapb); + lapb->state = LAPB_STATE_0; + lapb_disconnect_indication(lapb, LAPB_TIMEDOUT); + lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev); + lapb->t1timer_running = false; + goto out; + } else { + lapb->n2count++; + if (lapb->mode & LAPB_EXTENDED) { + lapb_dbg(1, "(%p) S1 TX SABME(1)\n", + lapb->dev); + lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND); + } else { + lapb_dbg(1, "(%p) S1 TX SABM(1)\n", + lapb->dev); + lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND); + } + } + break; + + /* + * Awaiting disconnection state, send DISC, up to N2 times. + */ + case LAPB_STATE_2: + if (lapb->n2count == lapb->n2) { + lapb_clear_queues(lapb); + lapb->state = LAPB_STATE_0; + lapb_disconnect_confirmation(lapb, LAPB_TIMEDOUT); + lapb_dbg(0, "(%p) S2 -> S0\n", lapb->dev); + lapb->t1timer_running = false; + goto out; + } else { + lapb->n2count++; + lapb_dbg(1, "(%p) S2 TX DISC(1)\n", lapb->dev); + lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND); + } + break; + + /* + * Data transfer state, restransmit I frames, up to N2 times. + */ + case LAPB_STATE_3: + if (lapb->n2count == lapb->n2) { + lapb_clear_queues(lapb); + lapb->state = LAPB_STATE_0; + lapb_stop_t2timer(lapb); + lapb_disconnect_indication(lapb, LAPB_TIMEDOUT); + lapb_dbg(0, "(%p) S3 -> S0\n", lapb->dev); + lapb->t1timer_running = false; + goto out; + } else { + lapb->n2count++; + lapb_requeue_frames(lapb); + lapb_kick(lapb); + } + break; + + /* + * Frame reject state, restransmit FRMR frames, up to N2 times. + */ + case LAPB_STATE_4: + if (lapb->n2count == lapb->n2) { + lapb_clear_queues(lapb); + lapb->state = LAPB_STATE_0; + lapb_disconnect_indication(lapb, LAPB_TIMEDOUT); + lapb_dbg(0, "(%p) S4 -> S0\n", lapb->dev); + lapb->t1timer_running = false; + goto out; + } else { + lapb->n2count++; + lapb_transmit_frmr(lapb); + } + break; + } + + lapb_start_t1timer(lapb); + +out: + spin_unlock_bh(&lapb->lock); +} -- cgit v1.3.1