On Thu, Jul 16, 2026 at 3:23 PM Borah, Chaitanya Kumar <[email protected]> wrote: > > > > On 7/16/2026 2:45 PM, Andrei Kuchynski wrote: > > On Thu, Jul 16, 2026 at 10:28 AM Borah, Chaitanya Kumar > > <[email protected]> wrote: > >> > >> Hello Andrei, > >> > >> On 7/7/2026 7:47 PM, Andrei Kuchynski wrote: > >>> A synchronization issue exists during port unregistration where pending > >>> partner work items can race against workqueue destruction, leading to > >>> use-after-free conditions: > >>> > >>> cros_ec_ucsi cros_ec_ucsi.3.auto: error -ETIMEDOUT: PPM init failed > >>> BUG: kernel NULL pointer dereference, address: 0000000000000000 > >>> RIP: 0010:__queue_work+0x83/0x4a0 > >>> Call Trace: > >>> <IRQ> > >>> __cfi_delayed_work_timer_fn+0x10/0x10 > >>> run_timer_softirq+0x3b6/0xbd0 > >>> sched_clock_cpu+0xc/0x110 > >>> irq_exit_rcu+0x18d/0x330 > >>> fred_sysvec_apic_timer_interrupt+0x5e/0x80 > >>> > >>> Fix this by ensuring strict ordering and proper serialization during > >>> teardown: > >>> > >>> 1. Move ucsi_unregister_partner() to the beginning of the teardown > >>> sequence and protect it under the connector mutex lock. > >>> 2. Ensure all pending partner tasks are explicitly flushed and finished > >>> before the workqueue is destroyed. > >>> 3. Switch from mod_delayed_work() to a cancel_delayed_work() and > >>> queue_delayed_work() sequence. This guarantees that items currently marked > >>> as pending won't be scheduled an additional time, preventing a double > >>> release of resources which leads to the following crash: > >>> > >>> Oops: general protection fault, probably for non-canonical address > >>> 0xdead000000000122: 0000 [#1] SMP NOPTI > >>> Workqueue: cros_ec_ucsi.3.auto-con2 ucsi_poll_worker > >>> RIP: 0010:ucsi_poll_worker+0x65/0x1e0 > >>> Call Trace: > >>> <TASK> > >>> process_scheduled_works+0x218/0x6d0 > >>> worker_thread+0x188/0x3f0 > >>> __cfi_worker_thread+0x10/0x10 > >>> kthread+0x226/0x2a0 > >>> > >>> To ensure these rules are applied identically across both the normal > >>> teardown and the ucsi_init() error paths, consolidate the cleanup logic > >>> into a new helper, ucsi_unregister_port(). > >> > >> > >> This seems to be causing regression in our linux-next CI. [1] > >> > >> <6>[ 18.008557] ------------[ cut here ]------------ > >> <4>[ 18.013166] DEBUG_LOCKS_WARN_ON(1) > >> <4>[ 18.013167] WARNING: kernel/locking/lockdep.c:238 at > >> __lock_acquire+0xa59/0x2750, CPU#1: kworker/u89:1/172 > >> ... > >> <4>[ 18.159950] Hardware name: Intel Corporation Meteor Lake Client > >> Platform/MTL-P DDR5 SODIMM SBS RVP, BIOS > >> MTLPFWI1.R00.3471.D89.2401091901 01/09/2024 > >> <4>[ 18.173125] Workqueue: events_dfl_long ucsi_init_work [typec_ucsi] > >> <4>[ 18.179257] RIP: 0010:__lock_acquire+0xa60/0x2750 > >> <4>[ 18.183927] Code: 44 8b 5d a8 85 c0 0f 84 98 fd ff ff 44 8b 35 07 > >> 0b 72 02 45 85 f6 0f 85 88 fd ff ff 48 8d 3d 27 25 73 02 48 c7 c6 1b 51 > >> 27 83 <67> 48 0f b9 3a 31 c0 44 8b 5d a8 44 8b 4d b0 e9 c6 f7 ff ff 31 d2 > >> ... > >> <4>[ 18.263886] PKRU: 55555554 > >> <4>[ 18.266583] Call Trace: > >> <4>[ 18.269014] <TASK> > >> <4>[ 18.271110] ? mark_held_locks+0x46/0x90 > >> <4>[ 18.275007] lock_acquire+0xd9/0x2e0 > >> <4>[ 18.278562] ? ucsi_unregister_port+0x36/0x140 [typec_ucsi] > >> <4>[ 18.284096] __mutex_lock+0xb2/0x1020 > >> <4>[ 18.287735] ? ucsi_unregister_port+0x36/0x140 [typec_ucsi] > >> <4>[ 18.293265] ? ucsi_unregister_port+0x36/0x140 [typec_ucsi] > >> <4>[ 18.298797] ? synchronize_rcu_expedited+0x2b2/0x300 > >> <4>[ 18.303724] ? __pfx_autoremove_wake_function+0x10/0x10 > >> <4>[ 18.308912] mutex_lock_nested+0x1b/0x30 > >> <4>[ 18.312806] ? mutex_lock_nested+0x1b/0x30 > >> <4>[ 18.316878] ucsi_unregister_port+0x36/0x140 [typec_ucsi] > >> <4>[ 18.322238] ucsi_init_work+0x66d/0xc10 [typec_ucsi] > >> <4>[ 18.327167] process_one_work+0x2ad/0x8b0 > >> <4>[ 18.331158] worker_thread+0x200/0x3f0 > >> <4>[ 18.334886] ? __pfx_worker_thread+0x10/0x10 > >> <4>[ 18.339128] kthread+0x10d/0x150 > >> <4>[ 18.342339] ? __pfx_kthread+0x10/0x10 > >> <4>[ 18.346067] ret_from_fork+0x3bd/0x470 > >> <4>[ 18.349795] ? __pfx_kthread+0x10/0x10 > >> <4>[ 18.353522] ret_from_fork_asm+0x1a/0x30 > >> <4>[ 18.357420] </TASK> > >> > >> Detailed log can be seen found in [2] > >> > >> We confirmed that reverting the patch solves the issue. > >> > >> Could you please check why the patch causes this regression and provide > >> a fix if necessary? > >> > >> Regards > >> Chaitanya > >> > >> [1] https://intel-gfx-ci.01.org/tree/linux-next/combined-alt.html? > >> [2] > >> https://intel-gfx-ci.01.org/tree/linux-next/next-20260714/bat-mtlp-9/boot0.txt > >> > >> -- Bisect Logs -- > >> > >> git bisect start > >> # status: waiting for both good and bad commits > >> # good: [5f1b513690edf51727e6928b97705b6437f9a98e] Merge remote-tracking > >> branch 'spi/for-7.3' into spi-next > >> git bisect good 5f1b513690edf51727e6928b97705b6437f9a98e > >> # status: waiting for bad commit, 1 good commit known > >> # bad: [49362394dad7df66c274c867a271394c10ca2bb8] Add linux-next > >> specific files for 20260713 > >> git bisect bad 49362394dad7df66c274c867a271394c10ca2bb8 > >> # bad: [dffddeb046466ed57038295bde28b42b7506a12b] Merge branch > >> 'nand/next' of > >> https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git > >> git bisect bad dffddeb046466ed57038295bde28b42b7506a12b > >> # bad: [d154d0766bf3fe830e1bf98fb2d8648294a4a8da] Merge branch > >> 'for-next' of > >> https://git.kernel.org/pub/scm/linux/kernel/git/khilman/linux-omap.git > >> git bisect bad d154d0766bf3fe830e1bf98fb2d8648294a4a8da > >> # bad: [671b0fd929bec9ebf863cb376baf9b9d1226a510] Merge branch 'master' > >> of https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux.git > >> git bisect bad 671b0fd929bec9ebf863cb376baf9b9d1226a510 > >> # good: [f4fb100039e96211609dfc44fb24b9e4a8a0f2f9] Merge tag > >> 's390-7.2-4' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux > >> git bisect good f4fb100039e96211609dfc44fb24b9e4a8a0f2f9 > >> # good: [c296d513e034df93ddb230ad1c7a118d6b58750c] Merge branch > >> 'arm/fixes' of https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git > >> git bisect good c296d513e034df93ddb230ad1c7a118d6b58750c > >> # good: [de53c0a584f08f31eb957f8c849a59fb33b27fa8] Merge branch 'for-rc' > >> of https://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git > >> git bisect good de53c0a584f08f31eb957f8c849a59fb33b27fa8 > >> # bad: [a6969de5a038bc08a948ada52bd7199a8dfa6cec] Merge branch > >> 'usb-linus' of > >> https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git > >> git bisect bad a6969de5a038bc08a948ada52bd7199a8dfa6cec > >> # good: [15eab2dd63a97587405ab6bfaad9728d5b35b5fe] Merge tag > >> 'asoc-fix-v7.2-rc2' of > >> https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into > >> for-linus > >> git bisect good 15eab2dd63a97587405ab6bfaad9728d5b35b5fe > >> # bad: [c2e819be6a5c7f34344926b4bd7e3dfca58cf48a] usb: gadget: printer: > >> fix infinite loop in printer_read() > >> git bisect bad c2e819be6a5c7f34344926b4bd7e3dfca58cf48a > >> # good: [29a142d3e8b35ebc9e0bcc78f4bc26c9b6a9ac0b] USB: gadget: > >> snps-udc: fix device name leak on probe failure > >> git bisect good 29a142d3e8b35ebc9e0bcc78f4bc26c9b6a9ac0b > >> # good: [1febec7e47cdcd01f43fb0211094e3010474666e] usb: gadget: f_ncm: > >> validate datagram bounds in ncm_unwrap_ntb() > >> git bisect good 1febec7e47cdcd01f43fb0211094e3010474666e > >> # bad: [0583f2fbf8f86ae3a0ce054f96783dd83e65d9bb] usb: gadget: udc: bdc: > >> free IRQ and drain func_wake_notify before teardown > >> git bisect bad 0583f2fbf8f86ae3a0ce054f96783dd83e65d9bb > >> # bad: [7aa7d4bf9d3fa9a6a47b640ad103ab433b7ff261] usb: typec: ucsi: Fix > >> race condition and ordering in port unregistration > >> git bisect bad 7aa7d4bf9d3fa9a6a47b640ad103ab433b7ff261 > >> # first bad commit: [7aa7d4bf9d3fa9a6a47b640ad103ab433b7ff261] usb: > >> typec: ucsi: Fix race condition and ordering in port unregistration > >>> > >>> Cc: [email protected] > >>> Fixes: b9aa02ca39a4 ("usb: typec: ucsi: Add polling mechanism for partner > >>> tasks like alt mode checking") > >>> Fixes: b13abcb7ddd8 ("usb: typec: ucsi: Fix NULL pointer access") > >>> Fixes: fac4b8633fd6 ("usb: ucsi: Ensure connector delayed work items are > >>> flushed") > >>> Signed-off-by: Andrei Kuchynski <[email protected]> > >>> --- > >>> drivers/usb/typec/ucsi/ucsi.c | 82 +++++++++++++++++------------------ > >>> 1 file changed, 39 insertions(+), 43 deletions(-) > >>> > >>> diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c > >>> index 92166a3725b16..d9668ed7c80ea 100644 > >>> --- a/drivers/usb/typec/ucsi/ucsi.c > >>> +++ b/drivers/usb/typec/ucsi/ucsi.c > >>> @@ -1845,6 +1845,42 @@ static int ucsi_register_port(struct ucsi *ucsi, > >>> struct ucsi_connector *con) > >>> return ret; > >>> } > >>> > >>> +static void ucsi_unregister_port(struct ucsi_connector *con) > >>> +{ > >>> + struct ucsi_work *uwork; > >>> + > >>> + if (con->wq) { > >>> + mutex_lock(&con->lock); > >>> + ucsi_unregister_partner(con); > >>> + /* > >>> + * queue delayed items immediately so they can execute > >>> + * and free themselves before the wq is destroyed > >>> + */ > >>> + list_for_each_entry(uwork, &con->partner_tasks, node) { > >>> + if (cancel_delayed_work(&uwork->work)) > >>> + queue_delayed_work(con->wq, &uwork->work, > >>> 0); > >>> + } > >>> + mutex_unlock(&con->lock); > >>> + > >>> + destroy_workqueue(con->wq); > >>> + con->wq = NULL; > >>> + } else { > >>> + ucsi_unregister_partner(con); > >>> + } > >>> + > >>> + ucsi_unregister_altmodes(con, UCSI_RECIPIENT_CON); > >>> + ucsi_unregister_port_psy(con); > >>> + > >>> + usb_power_delivery_unregister_capabilities(con->port_sink_caps); > >>> + con->port_sink_caps = NULL; > >>> + usb_power_delivery_unregister_capabilities(con->port_source_caps); > >>> + con->port_source_caps = NULL; > >>> + usb_power_delivery_unregister(con->pd); > >>> + con->pd = NULL; > >>> + typec_unregister_port(con->port); > >>> + con->port = NULL; > >>> +} > >>> + > >>> static u64 ucsi_get_supported_notifications(struct ucsi *ucsi) > >>> { > >>> u16 features = ucsi->cap.features; > >>> @@ -1971,22 +2007,8 @@ static int ucsi_init(struct ucsi *ucsi) > >>> for (i = 0; i < ucsi->cap.num_connectors; i++) > >>> lockdep_unregister_key(&connector[i].lock_key); > >>> > >>> - for (con = connector; con->port; con++) { > >>> - if (con->wq) > >>> - destroy_workqueue(con->wq); > >>> - ucsi_unregister_partner(con); > >>> - ucsi_unregister_altmodes(con, UCSI_RECIPIENT_CON); > >>> - ucsi_unregister_port_psy(con); > >>> - > >>> - > >>> usb_power_delivery_unregister_capabilities(con->port_sink_caps); > >>> - con->port_sink_caps = NULL; > >>> - > >>> usb_power_delivery_unregister_capabilities(con->port_source_caps); > >>> - con->port_source_caps = NULL; > >>> - usb_power_delivery_unregister(con->pd); > >>> - con->pd = NULL; > >>> - typec_unregister_port(con->port); > >>> - con->port = NULL; > >>> - } > >>> + for (con = connector; con->port; con++) > >>> + ucsi_unregister_port(con); > > > > Hi Chaitanya, > > Thank you for spotting this! > > > > Could you verify if calling lockdep_unregister_key(&connector[i].lock_key) > > after ucsi_unregister_port(con) resolves the issue? > > > > for (con = connector; con->port; con++) > > ucsi_unregister_port(con); > > for (i = 0; i < ucsi->cap.num_connectors; i++) > > lockdep_unregister_key(&connector[i].lock_key); > > > > I will also try testing this on my side. > > Thank you Andrei for the patch. It seems to work for us. >
Hi Chaitanya, Thanks for the testing! I will prepare a fix or maybe V2 of this patch. Could you please share your configuration details? Specifically, do you have any of the following enabled? CONFIG_DEBUG_LOCKDEP CONFIG_LOCK_STAT CONFIG_LOCKDEP_SMALL CONFIG_DEBUG_LOCKDEP CONFIG_PROVE_LOCKING I am still not able to reproduce it. Thanks, Andrei
