syzbot


INFO: task hung in i2c_smbus_xfer (4)

Status: auto-obsoleted due to no activity on 2026/02/27 11:15
Subsystems: i2c
[Documentation on labels]
First crash: 211d, last: 95d
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in i2c_smbus_xfer i2c 1 2 1290d 1300d 0/29 auto-obsoleted due to no activity on 2022/11/20 21:07
upstream INFO: task hung in i2c_smbus_xfer (3) i2c 1 3 706d 717d 0/29 auto-obsoleted due to no activity on 2024/06/27 07:58
upstream INFO: task hung in i2c_smbus_xfer (2) i2c 1 1 1102d 1102d 0/29 auto-obsoleted due to no activity on 2023/05/28 06:23

Sample crash report:
INFO: task syz.1.4753:22205 blocked for more than 430 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.4753      state:D stack:0     pid:22205 tgid:22204 ppid:21633  task_flags:0x400040 flags:0x00000001
Call trace: 
[<81a6483c>] (__schedule) from [<80295c94>] (__schedule_loop kernel/sched/core.c:7011 [inline])
[<81a6483c>] (__schedule) from [<80295c94>] (rt_mutex_schedule+0x20/0x38 kernel/sched/core.c:7307)
 r10:85933000 r9:00000002 r8:00000000 r7:df941d98 r6:df941da0 r5:85930c00
 r4:85930c00
[<80295c74>] (rt_mutex_schedule) from [<81a6b558>] (rt_mutex_slowlock_block.constprop.0+0x40/0x1d4 kernel/locking/rtmutex.c:1647)
 r5:85930c00 r4:83329854
[<81a6b518>] (rt_mutex_slowlock_block.constprop.0) from [<81a6c8b0>] (__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline])
[<81a6b518>] (rt_mutex_slowlock_block.constprop.0) from [<81a6c8b0>] (__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline])
[<81a6b518>] (rt_mutex_slowlock_block.constprop.0) from [<81a6c8b0>] (rt_mutex_slowlock.constprop.0+0xd4/0x364 kernel/locking/rtmutex.c:1800)
 r10:60000013 r9:df941da0 r8:00000002 r7:df941d98 r6:83329854 r5:00000000
 r4:85930c00
[<81a6c7dc>] (rt_mutex_slowlock.constprop.0) from [<81a6cc24>] (__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline])
[<81a6c7dc>] (rt_mutex_slowlock.constprop.0) from [<81a6cc24>] (__rt_mutex_lock_common kernel/locking/rtmutex_api.c:49 [inline])
[<81a6c7dc>] (rt_mutex_slowlock.constprop.0) from [<81a6cc24>] (rt_mutex_lock+0x44/0x48 kernel/locking/rtmutex_api.c:89)
 r10:00000022 r9:000000ab r8:00000000 r7:000000ab r6:00000000 r5:00000000
 r4:83329840
[<81a6cbe0>] (rt_mutex_lock) from [<810e7398>] (i2c_adapter_lock_bus+0x14/0x18 drivers/i2c/i2c-core-base.c:849)
[<810e7384>] (i2c_adapter_lock_bus) from [<810ecb90>] (i2c_lock_bus include/linux/i2c.h:809 [inline])
[<810e7384>] (i2c_adapter_lock_bus) from [<810ecb90>] (__i2c_lock_bus_helper drivers/i2c/i2c-core.h:46 [inline])
[<810e7384>] (i2c_adapter_lock_bus) from [<810ecb90>] (i2c_smbus_xfer+0xa4/0x12c drivers/i2c/i2c-core-smbus.c:542)
[<810ecaec>] (i2c_smbus_xfer) from [<810eea0c>] (i2cdev_ioctl_smbus+0xf4/0x384 drivers/i2c/i2c-dev.c:389)
 r8:00000022 r7:20000180 r6:00000000 r5:86a43c00 r4:00000008
[<810ee918>] (i2cdev_ioctl_smbus) from [<810eefa4>] (i2cdev_ioctl+0x308/0x404 drivers/i2c/i2c-dev.c:478)
 r10:85930c00 r9:00000003 r8:86677300 r7:20000200 r6:b5403587 r5:86a43c00
 r4:20000200
[<810eec9c>] (i2cdev_ioctl) from [<80578f40>] (vfs_ioctl fs/ioctl.c:51 [inline])
[<810eec9c>] (i2cdev_ioctl) from [<80578f40>] (do_vfs_ioctl fs/ioctl.c:551 [inline])
[<810eec9c>] (i2cdev_ioctl) from [<80578f40>] (__do_sys_ioctl fs/ioctl.c:595 [inline])
[<810eec9c>] (i2cdev_ioctl) from [<80578f40>] (sys_ioctl+0x130/0xba0 fs/ioctl.c:583)
 r6:86677301 r5:00000000 r4:00000720
[<80578e10>] (sys_ioctl) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:67)
Exception stack(0xdf941fa8 to 0xdf941ff0)
1fa0:                   00000000 00000000 00000003 00000720 20000200 00000000
1fc0: 00000000 00000000 00316308 00000036 00300000 00000000 00006364 76f480bc
1fe0: 76f47ec0 76f47eb0 00019294 00132a10
 r10:00000036 r9:85930c00 r8:8020029c r7:00000036 r6:00316308 r5:00000000
 r4:00000000
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT 
Hardware name: ARM-Versatile Express
Call trace: 
[<80201a24>] (dump_backtrace) from [<80201b20>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:00000000 r6:00000013 r5:60000093 r4:8225282c
[<80201b08>] (show_stack) from [<8021f8f8>] (__dump_stack lib/dump_stack.c:94 [inline])
[<80201b08>] (show_stack) from [<8021f8f8>] (dump_stack_lvl+0x70/0x7c lib/dump_stack.c:120)
[<8021f888>] (dump_stack_lvl) from [<8021f91c>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
 r5:00000000 r4:00000001
[<8021f904>] (dump_stack) from [<81a4e454>] (nmi_cpu_backtrace+0x160/0x17c lib/nmi_backtrace.c:113)
[<81a4e2f4>] (nmi_cpu_backtrace) from [<81a4e5a0>] (nmi_trigger_cpumask_backtrace+0x130/0x1d8 lib/nmi_backtrace.c:62)
 r7:00000000 r6:8280c690 r5:8281ae34 r4:ffffffff
[<81a4e470>] (nmi_trigger_cpumask_backtrace) from [<802304fc>] (arch_trigger_cpumask_backtrace+0x18/0x1c arch/arm/kernel/smp.c:852)
 r9:8281ba28 r8:8280c810 r7:00060d80 r6:00007f08 r5:82abf7d4 r4:8415b20c
[<802304e4>] (arch_trigger_cpumask_backtrace) from [<8037faf8>] (trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline])
[<802304e4>] (arch_trigger_cpumask_backtrace) from [<8037faf8>] (check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline])
[<802304e4>] (arch_trigger_cpumask_backtrace) from [<8037faf8>] (watchdog+0x5d0/0x850 kernel/hung_task.c:495)
[<8037f528>] (watchdog) from [<8028020c>] (kthread+0x12c/0x280 kernel/kthread.c:463)
 r10:00000000 r9:00000000 r8:8037f528 r7:830d6b00 r6:830d6b00 r5:8321d400
 r4:00000001
[<802800e0>] (kthread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:137)
Exception stack(0xdf8d9fb0 to 0xdf8d9ff8)
9fa0:                                     00000000 00000000 00000000 00000000
9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
9fe0: 00000000 00000000 00000000 00000000 00000013 00000000
 r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:802800e0
 r4:832c70c0
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 2818 Comm: pr/ttyAMA-1 Not tainted syzkaller #0 PREEMPT 
Hardware name: ARM-Versatile Express
PC is at kthread_should_stop+0x0/0x44 kernel/kthread.c:167
LR is at nbcon_kthread_func+0x134/0x2a4 kernel/printk/nbcon.c:1214
pc : [<802808f8>]    lr : [<802e38fc>]    psr: 20000113
sp : eaeb1ef8  ip : eaeb1ef8  fp : eaeb1f6c
r10: 82959594  r9 : 00000000  r8 : 00000001
r7 : 00000001  r6 : 8280c690  r5 : 84ba8c00  r4 : 829594f8
r3 : 84ba8c00  r2 : 00000000  r1 : 00000000  r0 : 82959594
Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
Control: 30c5387d  Table: 84fa3b40  DAC: 00000000
Call trace: 
[<802e37c8>] (nbcon_kthread_func) from [<8028020c>] (kthread+0x12c/0x280 kernel/kthread.c:463)
 r10:00000000 r9:829594f8 r8:802e37c8 r7:84762400 r6:84762400 r5:84ba8c00
 r4:00000001
[<802800e0>] (kthread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:137)
Exception stack(0xeaeb1fb0 to 0xeaeb1ff8)
1fa0:                                     00000000 00000000 00000000 00000000
1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
1fe0: 00000000 00000000 00000000 00000000 00000013 00000000
 r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:802800e0
 r4:8474f400

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/29 11:10 upstream 19eef1d98eed 01c07bfe .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 INFO: task hung in i2c_smbus_xfer
2025/09/20 06:48 upstream 1522b530ac3e 67c37560 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 INFO: task hung in i2c_smbus_xfer
2025/08/06 10:06 upstream 6bcdbd62bd56 ffe1dd46 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 INFO: task hung in i2c_smbus_xfer
* Struck through repros no longer work on HEAD.