The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 79d10f4f21a92e459b2276a77be62c59c1502c9d # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025100333-silica-pebble-c8d6@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 79d10f4f21a92e459b2276a77be62c59c1502c9d Mon Sep 17 00:00:00 2001 From: Duoming Zhou duoming@zju.edu.cn Date: Wed, 17 Sep 2025 17:57:42 +0800 Subject: [PATCH] media: i2c: tc358743: Fix use-after-free bugs caused by orphan timer in probe
The state->timer is a cyclic timer that schedules work_i2c_poll and delayed_work_enable_hotplug, while rearming itself. Using timer_delete() fails to guarantee the timer isn't still running when destroyed, similarly cancel_delayed_work() cannot ensure delayed_work_enable_hotplug has terminated if already executing. During probe failure after timer initialization, these may continue running as orphans and reference the already-freed tc358743_state object through tc358743_irq_poll_timer.
The following is the trace captured by KASAN.
BUG: KASAN: slab-use-after-free in __run_timer_base.part.0+0x7d7/0x8c0 Write of size 8 at addr ffff88800ded83c8 by task swapper/1/0 ... Call Trace: <IRQ> dump_stack_lvl+0x55/0x70 print_report+0xcf/0x610 ? __pfx_sched_balance_find_src_group+0x10/0x10 ? __run_timer_base.part.0+0x7d7/0x8c0 kasan_report+0xb8/0xf0 ? __run_timer_base.part.0+0x7d7/0x8c0 __run_timer_base.part.0+0x7d7/0x8c0 ? rcu_sched_clock_irq+0xb06/0x27d0 ? __pfx___run_timer_base.part.0+0x10/0x10 ? try_to_wake_up+0xb15/0x1960 ? tmigr_update_events+0x280/0x740 ? _raw_spin_lock_irq+0x80/0xe0 ? __pfx__raw_spin_lock_irq+0x10/0x10 tmigr_handle_remote_up+0x603/0x7e0 ? __pfx_tmigr_handle_remote_up+0x10/0x10 ? sched_balance_trigger+0x98/0x9f0 ? sched_tick+0x221/0x5a0 ? _raw_spin_lock_irq+0x80/0xe0 ? __pfx__raw_spin_lock_irq+0x10/0x10 ? tick_nohz_handler+0x339/0x440 ? __pfx_tmigr_handle_remote_up+0x10/0x10 __walk_groups.isra.0+0x42/0x150 tmigr_handle_remote+0x1f4/0x2e0 ? __pfx_tmigr_handle_remote+0x10/0x10 ? ktime_get+0x60/0x140 ? lapic_next_event+0x11/0x20 ? clockevents_program_event+0x1d4/0x2a0 ? hrtimer_interrupt+0x322/0x780 handle_softirqs+0x16a/0x550 irq_exit_rcu+0xaf/0xe0 sysvec_apic_timer_interrupt+0x70/0x80 </IRQ> ...
Allocated by task 141: kasan_save_stack+0x24/0x50 kasan_save_track+0x14/0x30 __kasan_kmalloc+0x7f/0x90 __kmalloc_node_track_caller_noprof+0x198/0x430 devm_kmalloc+0x7b/0x1e0 tc358743_probe+0xb7/0x610 i2c_device_probe+0x51d/0x880 really_probe+0x1ca/0x5c0 __driver_probe_device+0x248/0x310 driver_probe_device+0x44/0x120 __device_attach_driver+0x174/0x220 bus_for_each_drv+0x100/0x190 __device_attach+0x206/0x370 bus_probe_device+0x123/0x170 device_add+0xd25/0x1470 i2c_new_client_device+0x7a0/0xcd0 do_one_initcall+0x89/0x300 do_init_module+0x29d/0x7f0 load_module+0x4f48/0x69e0 init_module_from_file+0xe4/0x150 idempotent_init_module+0x320/0x670 __x64_sys_finit_module+0xbd/0x120 do_syscall_64+0xac/0x280 entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 141: kasan_save_stack+0x24/0x50 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3a/0x60 __kasan_slab_free+0x3f/0x50 kfree+0x137/0x370 release_nodes+0xa4/0x100 devres_release_group+0x1b2/0x380 i2c_device_probe+0x694/0x880 really_probe+0x1ca/0x5c0 __driver_probe_device+0x248/0x310 driver_probe_device+0x44/0x120 __device_attach_driver+0x174/0x220 bus_for_each_drv+0x100/0x190 __device_attach+0x206/0x370 bus_probe_device+0x123/0x170 device_add+0xd25/0x1470 i2c_new_client_device+0x7a0/0xcd0 do_one_initcall+0x89/0x300 do_init_module+0x29d/0x7f0 load_module+0x4f48/0x69e0 init_module_from_file+0xe4/0x150 idempotent_init_module+0x320/0x670 __x64_sys_finit_module+0xbd/0x120 do_syscall_64+0xac/0x280 entry_SYSCALL_64_after_hwframe+0x77/0x7f ...
Replace timer_delete() with timer_delete_sync() and cancel_delayed_work() with cancel_delayed_work_sync() to ensure proper termination of timer and work items before resource cleanup.
This bug was initially identified through static analysis. For reproduction and testing, I created a functional emulation of the tc358743 device via a kernel module and introduced faults through the debugfs interface.
Fixes: 869f38ae07f7 ("media: i2c: tc358743: Fix crash in the probe error path when using polling") Fixes: d32d98642de6 ("[media] Driver for Toshiba TC358743 HDMI to CSI-2 bridge") Cc: stable@vger.kernel.org Signed-off-by: Duoming Zhou duoming@zju.edu.cn Signed-off-by: Hans Verkuil hverkuil+cisco@kernel.org
diff --git a/drivers/media/i2c/tc358743.c b/drivers/media/i2c/tc358743.c index aa02a5a6ae3e..a0ca19359c43 100644 --- a/drivers/media/i2c/tc358743.c +++ b/drivers/media/i2c/tc358743.c @@ -2326,10 +2326,10 @@ static int tc358743_probe(struct i2c_client *client) err_work_queues: cec_unregister_adapter(state->cec_adap); if (!state->i2c_client->irq) { - timer_delete(&state->timer); + timer_delete_sync(&state->timer); flush_work(&state->work_i2c_poll); } - cancel_delayed_work(&state->delayed_work_enable_hotplug); + cancel_delayed_work_sync(&state->delayed_work_enable_hotplug); mutex_destroy(&state->confctl_mutex); err_hdl: media_entity_cleanup(&sd->entity);