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Message-ID: <aOz34fBN4z-Zuvnp@kuha.fi.intel.com> Date: Mon, 13 Oct 2025 16:00:17 +0300 From: Heikki Krogerus <heikki.krogerus@...ux.intel.com> To: "Chia-Lin Kao (AceLan)" <acelan.kao@...onical.com>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>, Andrei Kuchynski <akuchynski@...omium.org>, Łukasz Bartosik <ukaszb@...omium.org>, Venkat Jayaraman <venkat.jayaraman@...el.com>, linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH] usb: typec: ucsi: Fix workqueue destruction race during connector cleanup On Sun, Oct 12, 2025 at 10:00:03PM +0800, Chia-Lin Kao (AceLan) wrote: > On Thu, Oct 09, 2025 at 05:08:53PM +0300, Heikki Krogerus wrote: > > On Thu, Oct 09, 2025 at 09:58:22AM +0800, Chia-Lin Kao (AceLan) wrote: > > > On Wed, Oct 08, 2025 at 01:34:35PM +0300, Heikki Krogerus wrote: > > > > On Thu, Oct 02, 2025 at 09:30:26AM +0800, Chia-Lin Kao (AceLan) wrote: > > > > > During UCSI initialization and operation, there is a race condition where > > > > > delayed work items can be scheduled but attempt to queue work after the > > > > > workqueue has been destroyed. This occurs in multiple code paths. > > > > > > > > > > The race occurs when: > > > > > 1. ucsi_partner_task() or ucsi_poll_worker() schedule delayed work > > > > > 2. Connector cleanup paths call destroy_workqueue() > > > > > 3. Previously scheduled delayed work timers fire after destruction > > > > > 4. This triggers warnings and crashes in __queue_work() > > > > > > > > What warnings? > > > Here is what I got. > > > > > > Sep 24 13:24:22 ubuntu kernel: sysfs: cannot create duplicate filename '/devices/platform/USBC000:00/typec/port0/port0.0/partner' > > > Sep 24 13:24:22 ubuntu kernel: CPU: 1 UID: 0 PID: 132 Comm: kworker/u64:1 Tainted: G O 6.14.0-1012-oem #12-Ubuntu > > > Sep 24 13:24:22 ubuntu kernel: Tainted: [O]=OOT_MODULE > > > Sep 24 13:24:22 ubuntu kernel: Hardware name: Dell Inc. Dell /, BIOS XXXX XX/XX/2025 > > > Sep 24 13:24:22 ubuntu kernel: Workqueue: USBC000:00-con1 ucsi_poll_worker [typec_ucsi] > > > Sep 24 13:24:22 ubuntu kernel: Call Trace: > > > Sep 24 13:24:22 ubuntu kernel: <TASK> > > > Sep 24 13:24:22 ubuntu kernel: dump_stack_lvl+0x76/0xa0 > > > Sep 24 13:24:22 ubuntu kernel: dump_stack+0x10/0x20 > > > Sep 24 13:24:22 ubuntu kernel: sysfs_warn_dup+0x8a/0xb0 > > > Sep 24 13:24:22 ubuntu kernel: sysfs_do_create_link_sd+0xf1/0x100 > > > Sep 24 13:24:22 ubuntu kernel: sysfs_create_link+0x21/0x50 > > > Sep 24 13:24:22 ubuntu kernel: typec_probe+0x7e/0x100 [typec] > > > Sep 24 13:24:22 ubuntu kernel: ? driver_sysfs_add+0x66/0xd0 > > > Sep 24 13:24:22 ubuntu kernel: really_probe+0xee/0x3c0 > > > Sep 24 13:24:22 ubuntu kernel: __driver_probe_device+0x8c/0x180 > > > Sep 24 13:24:22 ubuntu kernel: driver_probe_device+0x24/0xd0 > > > Sep 24 13:24:22 ubuntu kernel: __device_attach_driver+0xcd/0x170 > > > Sep 24 13:24:22 ubuntu kernel: ? _pfx__device_attach_driver+0x10/0x10 > > > Sep 24 13:24:22 ubuntu kernel: bus_for_each_drv+0x94/0xf0 > > > Sep 24 13:24:22 ubuntu kernel: __device_attach+0xb6/0x1d0 > > > Sep 24 13:24:22 ubuntu kernel: device_initial_probe+0x13/0x20 > > > Sep 24 13:24:22 ubuntu kernel: bus_probe_device+0x9f/0xb0 > > > Sep 24 13:24:22 ubuntu kernel: device_add+0x513/0x710 > > > Sep 24 13:24:22 ubuntu kernel: device_register+0x1a/0x30 > > > Sep 24 13:24:22 ubuntu kernel: typec_register_altmode+0x253/0x3a0 [typec] > > > Sep 24 13:24:22 ubuntu kernel: typec_partner_register_altmode+0xe/0x20 [typec] > > > Sep 24 13:24:22 ubuntu kernel: ucsi_register_altmode.constprop.0+0x30e/0x390 [typec_ucsi] > > > Sep 24 13:24:22 ubuntu kernel: ucsi_register_altmodes+0x162/0x250 [typec_ucsi] > > > Sep 24 13:24:22 ubuntu kernel: ucsi_check_altmodes+0x19/0xb0 [typec_ucsi] > > > Sep 24 13:24:22 ubuntu kernel: ucsi_poll_worker+0x3d/0xf0 [typec_ucsi] > > > Sep 24 13:24:22 ubuntu kernel: process_one_work+0x178/0x3d0 > > > Sep 24 13:24:22 ubuntu kernel: worker_thread+0x2de/0x410 > > > Sep 24 13:24:22 ubuntu kernel: ? __pfx_worker_thread+0x10/0x10 > > > Sep 24 13:24:22 ubuntu kernel: kthread+0xfb/0x230 > > > Sep 24 13:24:22 ubuntu kernel: ? __pfx_kthread+0x10/0x10 > > > Sep 24 13:24:22 ubuntu kernel: ret_from_fork+0x44/0x70 > > > Sep 24 13:24:22 ubuntu kernel: ? __pfx_kthread+0x10/0x10 > > > Sep 24 13:24:22 ubuntu kernel: ret_from_fork_asm+0x1a/0x30 > > > Sep 24 13:24:22 ubuntu kernel: </TASK> > > > Sep 24 13:24:22 ubuntu kernel: typec-thunderbolt port0-partner.1: failed to create symlinks > > > Sep 24 13:24:22 ubuntu kernel: typec-thunderbolt port0-partner.1: probe with driver typec-thunderbolt failed with error -17 > > > > That does not look like anything you described in the commit message? > > > > You have there an attempt to register the same alternate mode twice, > > but the workqueue seems to be very much alive when that happens. > > > > Based on the above this looks like either a race where the driver > > really ends up registering the alternate modes multiple times or, and > > more likely, the firmware is reporting the same alternate mode > > multiple times. > > > > Or am I missing something? > Here is another one. It's not immediately obvious how this one relates to typec_ucsi. > > [ 170.605181] ucsi_acpi USBC000:00: con2: failed to register alt modes > [ 181.868900] ------------[ cut here ]------------ > [ 181.868905] workqueue: cannot queue ucsi_poll_worker [typec_ucsi] on wq USBC000:00-con1 > [ 181.868918] WARNING: CPU: 1 PID: 0 at kernel/workqueue.c:2255 __queue_work+0x420/0x5a0 > ... > [ 181.869062] CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.17.0-rc7+ #1 PREEMPT(voluntary) > [ 181.869065] Hardware name: Dell Inc. , BIOS xx.xx.xx xx/xx/2025 > [ 181.869067] RIP: 0010:__queue_work+0x420/0x5a0 > [ 181.869070] Code: 00 00 41 83 e4 01 0f 85 57 fd ff ff 49 8b 77 18 48 8d 93 c0 00 00 00 48 c7 c7 00 8c bc 92 c6 05 27 47 68 02 01 e8 50 24 fd f > f <0f> 0b e9 32 fd ff ff 0f 0b e9 1d fd ff ff 0f 0b e9 0f fd ff ff 0f > [ 181.869072] RSP: 0018:ffffd53c000acdf8 EFLAGS: 00010046 > [ 181.869075] RAX: 0000000000000000 RBX: ffff8ecd0727f200 RCX: 0000000000000000 > [ 181.869076] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 > [ 181.869077] RBP: ffffd53c000ace38 R08: 0000000000000000 R09: 0000000000000000 > [ 181.869078] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 > [ 181.869079] R13: ffffffff913995e0 R14: ffff8ecc824387a0 R15: ffff8ecc82438780 > [ 181.869081] FS: 0000000000000000(0000) GS:ffff8eec0b92f000(0000) knlGS:0000000000000000 > [ 181.869083] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 181.869084] CR2: 000005593e67a008 CR3: 0000001f41840002 CR4: 0000000000f72ef0 > [ 181.869086] PKRU: 55555554 > [ 181.869087] Call Trace: > [ 181.869089] <IRQ> > [ 181.869093] ? sched_clock+0x10/0x30 > [ 181.869098] ? __pfx_delayed_work_timer_fn+0x10/0x10 > [ 181.869100] delayed_work_timer_fn+0x19/0x30 > [ 181.869102] call_timer_fn+0x2c/0x150 > [ 181.869106] ? __pfx_delayed_work_timer_fn+0x10/0x10 > [ 181.869108] __run_timers+0x1c6/0x2d0 > [ 181.869111] run_timer_softirq+0x8a/0x100 > [ 181.869114] handle_softirqs+0xe4/0x340 > [ 181.869118] __irq_exit_rcu+0x10e/0x130 > [ 181.869121] irq_exit_rcu+0xe/0x20 > [ 181.869124] sysvec_apic_timer_interrupt+0xa0/0xc0 > [ 181.869130] </IRQ> > [ 181.869131] <TASK> > [ 181.869132] asm_sysvec_apic_timer_interrupt+0x1b/0x20 [ 181.869135] RIP: 0010:cpuidle_enter_state+0xda/0x710 > [ 181.869137] Code: 8f f7 fe e8 78 f0 ff ff 8b 53 04 49 89 c7 0f 1f 44 00 00 31 ff e8 86 bf f5 fe 80 7d d0 00 0f 85 22 02 00 00 fb 0f 1f 44 00 0 > 0 <45> 85 f6 0f 88 f2 01 00 00 4d 63 ee 49 83 fd 0a 0f 83 d8 04 00 00 > [ 181.869139] RSP: 0018:ffffd53c0022be18 EFLAGS: 00000246 > [ 181.869140] RAX: 0000000000000000 RBX: ffff8eeb9f8bf880 RCX: 0000000000000000 > [ 181.869142] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000000 > [ 181.869143] RBP: ffffd53c0022be68 R08: 0000000000000000 R09: 0000000000000000 > [ 181.869144] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff93914780 > [ 181.869145] R13: 0000000000000002 R14: 0000000000000002 R15: 0000002a583b0b41 > [ 181.869148] ? cpuidle_enter_state+0xca/0x710 > [ 181.869151] cpuidle_enter+0x2e/0x50 > [ 181.869156] call_cpuidle+0x22/0x60 > [ 181.869160] do_idle+0x1dc/0x240 > [ 181.869163] cpu_startup_entry+0x29/0x30 > [ 181.869164] start_secondary+0x128/0x160 > [ 181.869167] common_startup_64+0x13e/0x141 > [ 181.869171] </TASK> > [ 181.869172] ---[ end trace 0000000000000000 ]--- > [ 226.924460] workqueue USBC000:00-con1: drain_workqueue() isn't complete after 10 tries > [ 329.470977] ucsi_acpi USBC000:00: error -ETIMEDOUT: PPM init failed Okay, so to me it looks like there are two separate issues here. The first one looks like an EC (or PD controller) firmware related issue, where the response to the GET_ALTERNATE_MODES command is getting corrupted for some reason, and second is this race that you see as a consequence from the first FW related issue. So this patch is for the second issue - the race. I'll wait for the v2 from you guys. But I want to solve both issues. thanks, -- heikki
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