KCSAN: data-race in acpi_ut_trace_ptr / acpi_ut_trace_ptr

Status: moderation: reported on 2026/08/15 17:59
Subsystems: acpica
Labels: race:benign prio:low
[Documentation on labels]
Reported-by: syzbot+5052b8f9ee4c3426b1b6@syzkaller.appspotmail.com
First crash: 3d04h, last: 3d04h
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
494906d1 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ KCSAN: data-race in acpi_ut_trace_ptr / acpi_ut_trace_ptr 2026/08/17 02:57 2026/08/17 02:57 2026/08/17 02:58 746171ee
6c485f5a assessment-kcsan Benign: ✅ KCSAN: data-race in acpi_ut_trace_ptr / acpi_ut_trace_ptr 2026/08/15 19:27 2026/08/15 19:27 2026/08/15 19:56 746171ee

Sample crash report:
==================================================================
BUG: KCSAN: data-race in acpi_ut_trace_ptr / acpi_ut_trace_ptr

read-write to 0xffffffff89410638 of 4 bytes by task 30 on cpu 1:
 acpi_ut_trace_ptr+0x49/0x180 drivers/acpi/acpica/utdebug.c:306
 acpi_ns_handle_to_pathname+0x3b/0x1d0 drivers/acpi/acpica/nsnames.c:138
 acpi_rs_create_pci_routing_table+0x41a/0x760 drivers/acpi/acpica/rscreate.c:314
 acpi_rs_get_prt_method_data+0xa3/0x100 drivers/acpi/acpica/rsutils.c:456
 acpi_get_irq_routing_table+0x98/0xe0 drivers/acpi/acpica/rsxface.c:137
 acpi_pci_irq_find_prt_entry+0xb3/0x6e0 drivers/acpi/pci_irq.c:215
 acpi_pci_irq_lookup+0x3e/0x330 drivers/acpi/pci_irq.c:299
 acpi_pci_irq_enable+0x13a/0x3d0 drivers/acpi/pci_irq.c:414
 pcibios_enable_device+0x88/0xa0 arch/x86/pci/common.c:699
 do_pci_enable_device+0x152/0x2d0 drivers/pci/pci.c:1998
 pci_enable_device_flags+0x348/0x3a0 drivers/pci/pci.c:2089
 pci_enable_device+0x1a/0xa0 drivers/pci/pci.c:2122
 i801_probe+0x288/0xbf0 drivers/i2c/busses/i2c-i801.c:1573
 local_pci_probe drivers/pci/pci-driver.c:332 [inline]
 pci_call_probe drivers/pci/pci-driver.c:394 [inline]
 __pci_device_probe drivers/pci/pci-driver.c:455 [inline]
 pci_device_probe+0x28b/0x510 drivers/pci/pci-driver.c:489
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x1ba/0x600 drivers/base/dd.c:706
 __driver_probe_device+0x14f/0x1c0 drivers/base/dd.c:868
 driver_probe_device+0x37/0x2f0 drivers/base/dd.c:898
 __driver_attach_async_helper+0xb6/0x130 drivers/base/dd.c:1224
 async_run_entry_fn+0x52/0x180 kernel/async.c:129
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405
 worker_thread+0x569/0x750 kernel/workqueue.c:3486
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read-write to 0xffffffff89410638 of 4 bytes by task 49 on cpu 0:
 acpi_ut_trace_ptr+0x49/0x180 drivers/acpi/acpica/utdebug.c:306
 acpi_ns_build_normalized_path+0x43/0x420 drivers/acpi/acpica/nsnames.c:202
 acpi_ns_get_pathname_length+0x3f/0x70 drivers/acpi/acpica/nsnames.c:65
 acpi_rs_get_pci_routing_table_length+0x1f2/0x2b0 drivers/acpi/acpica/rscalc.c:817
 acpi_rs_create_pci_routing_table+0x79/0x760 drivers/acpi/acpica/rscreate.c:201
 acpi_rs_get_prt_method_data+0xa3/0x100 drivers/acpi/acpica/rsutils.c:456
 acpi_get_irq_routing_table+0x98/0xe0 drivers/acpi/acpica/rsxface.c:137
 acpi_pci_irq_find_prt_entry+0xb3/0x6e0 drivers/acpi/pci_irq.c:215
 acpi_pci_irq_lookup+0x3e/0x330 drivers/acpi/pci_irq.c:299
 acpi_pci_irq_enable+0x13a/0x3d0 drivers/acpi/pci_irq.c:414
 pcibios_enable_device+0x88/0xa0 arch/x86/pci/common.c:699
 do_pci_enable_device+0x152/0x2d0 drivers/pci/pci.c:1998
 pci_enable_device_flags+0x348/0x3a0 drivers/pci/pci.c:2089
 pci_enable_device+0x1a/0xa0 drivers/pci/pci.c:2122
 i801_probe+0x288/0xbf0 drivers/i2c/busses/i2c-i801.c:1573
 local_pci_probe drivers/pci/pci-driver.c:332 [inline]
 pci_call_probe drivers/pci/pci-driver.c:394 [inline]
 __pci_device_probe drivers/pci/pci-driver.c:455 [inline]
 pci_device_probe+0x28b/0x510 drivers/pci/pci-driver.c:489
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x1ba/0x600 drivers/base/dd.c:706
 __driver_probe_device+0x14f/0x1c0 drivers/base/dd.c:868
 driver_probe_device+0x37/0x2f0 drivers/base/dd.c:898
 __driver_attach_async_helper+0xb6/0x130 drivers/base/dd.c:1224
 async_run_entry_fn+0x52/0x180 kernel/async.c:129
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405
 worker_thread+0x569/0x750 kernel/workqueue.c:3486
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x0000000c -> 0x0000000e

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 49 Comm: kworker/u8:3 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: async async_run_entry_fn
==================================================================
ACPI: \_SB_.LNKA: Enabled at IRQ 11
i801_smbus 0000:00:05.0: SMBus base address uninitialized, upgrade BIOS

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/15 17:58 upstream 15ef2f78c49d 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in acpi_ut_trace_ptr / acpi_ut_trace_ptr
* Struck through repros no longer work on HEAD.