WARNING in trace_event_raw_event_smbus_write

Status: upstream: reported on 2026/08/11 09:19
Reported-by: syzbot+2799d6178a1f91625aa4@syzkaller.appspotmail.com
First crash: 6d22h, last: 6d22h

Sample crash report:
------------[ cut here ]------------
memcpy: detected field-spanning write (size 35) of single field "entry->buf" at include/trace/events/smbus.h:60 (size 34)
WARNING: CPU: 0 PID: 7633 at include/trace/events/smbus.h:60 do_trace_event_raw_event_smbus_write include/trace/events/smbus.h:60 [inline]
WARNING: CPU: 0 PID: 7633 at include/trace/events/smbus.h:60 trace_event_raw_event_smbus_write+0x338/0x44c include/trace/events/smbus.h:23
Modules linked in:
CPU: 0 PID: 7633 Comm: syz.8.658 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
pstate: 62400005 (nZCv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : do_trace_event_raw_event_smbus_write include/trace/events/smbus.h:60 [inline]
pc : trace_event_raw_event_smbus_write+0x338/0x44c include/trace/events/smbus.h:23
lr : do_trace_event_raw_event_smbus_write include/trace/events/smbus.h:60 [inline]
lr : trace_event_raw_event_smbus_write+0x338/0x44c include/trace/events/smbus.h:23
sp : ffff8000211e77c0
x29: ffff8000211e7880 x28: dfff800000000000 x27: ffff70000423cefc
x26: ffff8000211e77e0 x25: ffff0000cbe85118 x24: 0000000000000000
x23: 0000000000000000 x22: ffff8000211e7b60 x21: 0000000000000023
x20: ffff0000c0031a14 x19: ffff800017d5e000 x18: 0000000000000000
x17: 20646c6569662065 x16: ffff8000082dd248 x15: 0000000000000002
x14: 0000000000000001 x13: 1ffff0000423ce48 x12: 0000000000080000
x11: 0000000000006e06 x10: ffff800033f4f000 x9 : 862bb9f6abf09c00
x8 : 862bb9f6abf09c00 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff8000211e7258 x4 : ffff800015464e80 x3 : ffff80000831d354
x2 : 0000000000000001 x1 : 0000000000000002 x0 : 0000000000000000
Call trace:
 do_trace_event_raw_event_smbus_write include/trace/events/smbus.h:60 [inline]
 trace_event_raw_event_smbus_write+0x338/0x44c include/trace/events/smbus.h:23
 __traceiter_smbus_write include/trace/events/smbus.h:23 [inline]
 trace_smbus_write include/trace/events/smbus.h:23 [inline]
 __i2c_smbus_xfer+0x2110/0x23f0 drivers/i2c/i2c-core-smbus.c:571
 i2c_smbus_xfer+0x1f0/0x314 drivers/i2c/i2c-core-smbus.c:545
 i2cdev_ioctl_smbus+0x444/0x698 drivers/i2c/i2c-dev.c:381
 i2cdev_ioctl+0x744/0x984 drivers/i2c/i2c-dev.c:467
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x200/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
irq event stamp: 1250
hardirqs last  enabled at (1249): [<ffff80000831388c>] __up_console_sem+0xb4/0xfc kernel/printk/printk.c:261
hardirqs last disabled at (1250): [<ffff800011b8c2bc>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405
softirqs last  enabled at (1244): [<ffff8000081ae3bc>] softirq_handle_end kernel/softirq.c:439 [inline]
softirqs last  enabled at (1244): [<ffff8000081ae3bc>] handle_softirqs+0xb1c/0xc90 kernel/softirq.c:624
softirqs last disabled at (1235): [<ffff800008020e6c>] __do_softirq+0x14/0x20 kernel/softirq.c:630
---[ end trace 0000000000000000 ]---
==================================================================
BUG: KASAN: stack-out-of-bounds in do_trace_event_raw_event_smbus_write include/trace/events/smbus.h:60 [inline]
BUG: KASAN: stack-out-of-bounds in trace_event_raw_event_smbus_write+0x294/0x44c include/trace/events/smbus.h:23
Read of size 35 at addr ffff8000211e7b60 by task syz.8.658/7633

CPU: 0 PID: 7633 Comm: syz.8.658 Tainted: G        W          syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
Call trace:
 dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
 print_address_description+0x88/0x218 mm/kasan/report.c:316
 print_report+0x50/0x68 mm/kasan/report.c:420
 kasan_report+0xa8/0xfc mm/kasan/report.c:524
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x258/0x290 mm/kasan/generic.c:189
 memcpy+0x48/0x90 mm/kasan/shadow.c:65
 do_trace_event_raw_event_smbus_write include/trace/events/smbus.h:60 [inline]
 trace_event_raw_event_smbus_write+0x294/0x44c include/trace/events/smbus.h:23
 __traceiter_smbus_write include/trace/events/smbus.h:23 [inline]
 trace_smbus_write include/trace/events/smbus.h:23 [inline]
 __i2c_smbus_xfer+0x2110/0x23f0 drivers/i2c/i2c-core-smbus.c:571
 i2c_smbus_xfer+0x1f0/0x314 drivers/i2c/i2c-core-smbus.c:545
 i2cdev_ioctl_smbus+0x444/0x698 drivers/i2c/i2c-dev.c:381
 i2cdev_ioctl+0x744/0x984 drivers/i2c/i2c-dev.c:467
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x200/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to stack of task syz.8.658/7633
 and is located at offset 32 in frame:
 i2cdev_ioctl_smbus+0x0/0x698 drivers/i2c/i2c-dev.c:309

This frame has 1 object:
 [32, 66) 'temp'

The buggy address belongs to a 8-page vmalloc region starting at 0xffff8000211e0000 allocated at copy_process+0x4ec/0x38f4 kernel/fork.c:2188
The buggy address belongs to the physical page:
page:000000006c941d0d refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12b350
memcg:ffff0000db5f7702
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff ffff0000db5f7702
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8000211e7a80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8000211e7b00: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00
>ffff8000211e7b80: 02 f3 f3 f3 f3 f3 f3 f3 00 00 00 00 00 00 00 00
                   ^
 ffff8000211e7c00: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 f8 f2 f8 f8
 ffff8000211e7c80: f2 f2 00 00 f3 f3 f3 f3 00 00 00 00 00 00 00 00
==================================================================
i2c i2c-0: Invalid block write size 34

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/11 09:19 linux-6.1.y e4f7d8be268e 508909ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in trace_event_raw_event_smbus_write
* Struck through repros no longer work on HEAD.