[v6.1] KASAN: slab-out-of-bounds Write in dtv5100_i2c_msg

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 50cbba13faa2 Linux 6.1.159
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=109f8d58580000
kernel config: https://syzkaller.appspot.com/x/.config?x=31ea1cecaf34f0db
dashboard link: https://syzkaller.appspot.com/bug?extid=ec64e4e37e67c62c4654
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7ad0bd66715a/disk-50cbba13.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3284d626258e/vmlinux-50cbba13.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a1f92ca7bbfc/Image-50cbba13.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ec64e4...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in dtv5100_i2c_msg+0x17c/0x270 drivers/media/usb/dvb-usb/dtv5100.c:58
Write of size 83 at addr ffff0000f50d0000 by task syz.0.1077/7199

CPU: 0 PID: 7199 Comm: syz.0.1077 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
Call trace:
dump_backtrace+0x1c8/0x1f4 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+0xf8/0x160 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+0xa8/0x100 mm/kasan/report.c:524
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x260/0x2a0 mm/kasan/generic.c:189
memcpy+0x60/0x90 mm/kasan/shadow.c:66
dtv5100_i2c_msg+0x17c/0x270 drivers/media/usb/dvb-usb/dtv5100.c:58
dtv5100_i2c_xfer+0x210/0x358 drivers/media/usb/dvb-usb/dtv5100.c:81
__i2c_transfer+0x610/0x21c0 drivers/i2c/i2c-core-base.c:-1
i2c_transfer+0x1c8/0x2e4 drivers/i2c/i2c-core-base.c:2333
i2cdev_ioctl_rdwr+0x318/0x680 drivers/i2c/i2c-dev.c:297
i2cdev_ioctl+0x74c/0x948 drivers/i2c/i2c-dev.c:458
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+0x98/0x2bc arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x138 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

Allocated by task 14:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4c/0x80 mm/kasan/common.c:52
kasan_save_alloc_info+0x28/0x34 mm/kasan/generic.c:505
____kasan_kmalloc mm/kasan/common.c:374 [inline]
__kasan_kmalloc+0xa0/0xb8 mm/kasan/common.c:383
kasan_kmalloc include/linux/kasan.h:211 [inline]
__do_kmalloc_node mm/slab_common.c:936 [inline]
__kmalloc+0xec/0x178 mm/slab_common.c:949
kmalloc include/linux/slab.h:568 [inline]
kzalloc include/linux/slab.h:699 [inline]
dvb_usb_init drivers/media/usb/dvb-usb/dvb-usb-init.c:167 [inline]
dvb_usb_device_init+0x6e4/0x1958 drivers/media/usb/dvb-usb/dvb-usb-init.c:310
dtv5100_probe+0x288/0x2c4 drivers/media/usb/dvb-usb/dtv5100.c:157
usb_probe_interface+0x4fc/0x994 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x39c/0xae0 drivers/base/dd.c:639
__driver_probe_device+0x180/0x314 drivers/base/dd.c:785
driver_probe_device+0x78/0x330 drivers/base/dd.c:815
__device_attach_driver+0x290/0x4e0 drivers/base/dd.c:943
bus_for_each_drv+0x150/0x1d8 drivers/base/bus.c:429
__device_attach+0x2a8/0x3d4 drivers/base/dd.c:1015
device_initial_probe+0x24/0x34 drivers/base/dd.c:1064
bus_probe_device+0xbc/0x1c4 drivers/base/bus.c:489
device_add+0xb04/0xf94 drivers/base/core.c:3697
usb_set_configuration+0x1598/0x1b0c drivers/usb/core/message.c:2165
usb_generic_driver_probe+0x8c/0x144 drivers/usb/core/generic.c:238
usb_probe_device+0x120/0x25c drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x39c/0xae0 drivers/base/dd.c:639
__driver_probe_device+0x180/0x314 drivers/base/dd.c:785
driver_probe_device+0x78/0x330 drivers/base/dd.c:815
__device_attach_driver+0x290/0x4e0 drivers/base/dd.c:943
bus_for_each_drv+0x150/0x1d8 drivers/base/bus.c:429
__device_attach+0x2a8/0x3d4 drivers/base/dd.c:1015
device_initial_probe+0x24/0x34 drivers/base/dd.c:1064
bus_probe_device+0xbc/0x1c4 drivers/base/bus.c:489
device_add+0xb04/0xf94 drivers/base/core.c:3697
usb_new_device+0x7f0/0x11c4 drivers/usb/core/hub.c:2659
hub_port_connect drivers/usb/core/hub.c:5517 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5657 [inline]
port_event drivers/usb/core/hub.c:5817 [inline]
hub_event+0x221c/0x3e2c drivers/usb/core/hub.c:5899
process_one_work+0x7f4/0x13a8 kernel/workqueue.c:2292
worker_thread+0x8c8/0xfbc kernel/workqueue.c:2439
kthread+0x250/0x2d8 kernel/kthread.c:376
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850

Last potentially related work creation:
kasan_save_stack+0x40/0x70 mm/kasan/common.c:45
__kasan_record_aux_stack+0xc0/0xdc mm/kasan/generic.c:486
kasan_record_aux_stack_noalloc+0x14/0x20 mm/kasan/generic.c:496
kvfree_call_rcu+0xb4/0x6f0 kernel/rcu/tree.c:3405
kernfs_unlink_open_file+0x37c/0x42c fs/kernfs/file.c:653
kernfs_fop_release+0x128/0x190 fs/kernfs/file.c:825
__fput+0x1bc/0x7c0 fs/file_table.c:320
____fput+0x20/0x30 fs/file_table.c:348
task_work_run+0x1ec/0x270 kernel/task_work.c:203
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
do_notify_resume+0x2038/0x2b28 arch/arm64/kernel/signal.c:1137
prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
el0_svc+0x98/0x138 arch/arm64/kernel/entry-common.c:638
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 the object at ffff0000f50d0000
which belongs to the cache kmalloc-128 of size 128
The buggy address is located 0 bytes inside of
128-byte region [ffff0000f50d0000, ffff0000f50d0080)

The buggy address belongs to the physical page:
page:0000000065268c92 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1350d0
flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000200 fffffc0003f4a580 dead000000000002 ffff0000c0002300
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff0000f50cff00: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc
ffff0000f50cff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff0000f50d0000: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
^
ffff0000f50d0080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff0000f50d0100: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 50cbba13faa2 Linux 6.1.159
git tree: linux-6.1.y

console output: https://syzkaller.appspot.com/x/log.txt?x=1078dd92580000

kernel config: https://syzkaller.appspot.com/x/.config?x=31ea1cecaf34f0db
dashboard link: https://syzkaller.appspot.com/bug?extid=ec64e4e37e67c62c4654
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: arm64

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1255bdc2580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15bd3a2a580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7ad0bd66715a/disk-50cbba13.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3284d626258e/vmlinux-50cbba13.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a1f92ca7bbfc/Image-50cbba13.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ec64e4...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in dtv5100_i2c_msg+0x17c/0x270 drivers/media/usb/dvb-usb/dtv5100.c:58

Write of size 83 at addr ffff0000cd540100 by task syz.0.17/4509

CPU: 0 PID: 4509 Comm: syz.0.17 Not tainted syzkaller #0

Allocated by task 4396:

The buggy address belongs to the object at ffff0000cd540100

which belongs to the cache kmalloc-128 of size 128
The buggy address is located 0 bytes inside of

128-byte region [ffff0000cd540100, ffff0000cd540180)

The buggy address belongs to the physical page:

page:00000000db13f6f0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10d540

flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff)

raw: 05ffc00000000200 dead000000000100 dead000000000122 ffff0000c0002300

raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:

ffff0000cd540000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff0000cd540080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff0000cd540100: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
^
ffff0000cd540180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff0000cd540200: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 68efe5a6c16a Linux 5.15.197
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=117e8984580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7e6ed99963d6ee1d
dashboard link: https://syzkaller.appspot.com/bug?extid=d835ed9e3eb9fb8d21ab

compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/900f9b9bd850/disk-68efe5a6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1e089a5019a6/vmlinux-68efe5a6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b319f477b907/bzImage-68efe5a6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:

Reported-by: syzbot+d835ed...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in dtv5100_i2c_msg+0x1db/0x2d0 drivers/media/usb/dvb-usb/dtv5100.c:58
Write of size 83 at addr ffff88805f5c5d80 by task syz.3.1122/9002

CPU: 0 PID: 9002 Comm: syz.3.1122 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
<TASK>
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
print_address_description+0x60/0x2d0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:434 [inline]
kasan_report+0xdf/0x130 mm/kasan/report.c:451
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x27b/0x290 mm/kasan/generic.c:189
memcpy+0x3c/0x60 mm/kasan/shadow.c:66
dtv5100_i2c_msg+0x1db/0x2d0 drivers/media/usb/dvb-usb/dtv5100.c:58
dtv5100_i2c_xfer+0x47c/0x650 drivers/media/usb/dvb-usb/dtv5100.c:81
__i2c_transfer+0x864/0x2060 drivers/i2c/i2c-core-base.c:-1
i2c_transfer+0x24c/0x390 drivers/i2c/i2c-core-base.c:2330
i2cdev_ioctl_rdwr+0x3da/0x6c0 drivers/i2c/i2c-dev.c:297
i2cdev_ioctl+0x5ba/0x750 drivers/i2c/i2c-dev.c:458
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f7c56ddf749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7c55046038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f7c57035fa0 RCX: 00007f7c56ddf749
RDX: 00002000000002c0 RSI: 0000000000000707 RDI: 0000000000000004
RBP: 00007f7c56e63f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7c57036038 R14: 00007f7c57035fa0 R15: 00007ffd585c7858
</TASK>

Allocated by task 4521:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
____kasan_kmalloc mm/kasan/common.c:513 [inline]
__kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522
kmalloc include/linux/slab.h:612 [inline]
kzalloc include/linux/slab.h:738 [inline]
dvb_usb_init drivers/media/usb/dvb-usb/dvb-usb-init.c:167 [inline]
dvb_usb_device_init+0xc5e/0x23f0 drivers/media/usb/dvb-usb/dvb-usb-init.c:310
usb_probe_interface+0x5a0/0xaf0 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x284/0xc80 drivers/base/dd.c:595
__driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
driver_probe_device+0x4f/0x420 drivers/base/dd.c:785
__device_attach_driver+0x2b0/0x500 drivers/base/dd.c:907
bus_for_each_drv+0x175/0x200 drivers/base/bus.c:429
__device_attach+0x29b/0x460 drivers/base/dd.c:979
bus_probe_device+0xbc/0x1e0 drivers/base/bus.c:489
device_add+0xa00/0xfb0 drivers/base/core.c:3412
usb_set_configuration+0x1991/0x1fd0 drivers/usb/core/message.c:2165
usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
usb_probe_device+0x139/0x270 drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x284/0xc80 drivers/base/dd.c:595
__driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
driver_probe_device+0x4f/0x420 drivers/base/dd.c:785
__device_attach_driver+0x2b0/0x500 drivers/base/dd.c:907
bus_for_each_drv+0x175/0x200 drivers/base/bus.c:429
__device_attach+0x29b/0x460 drivers/base/dd.c:979
bus_probe_device+0xbc/0x1e0 drivers/base/bus.c:489
device_add+0xa00/0xfb0 drivers/base/core.c:3412
usb_new_device+0xd53/0x1640 drivers/usb/core/hub.c:2632
hub_port_connect drivers/usb/core/hub.c:5497 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5637 [inline]
port_event drivers/usb/core/hub.c:5799 [inline]
hub_event+0x2dd9/0x5560 drivers/usb/core/hub.c:5881
process_one_work+0x863/0x1000 kernel/workqueue.c:2310
worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Last potentially related work creation:

kasan_save_stack+0x35/0x60 mm/kasan/common.c:38
kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348
kvfree_call_rcu+0x10a/0x7c0 kernel/rcu/tree.c:3600
cfg80211_update_known_bss+0x178/0xa20 net/wireless/scan.c:-1
cfg80211_bss_update+0x15f/0x2250 net/wireless/scan.c:1836
cfg80211_inform_single_bss_frame_data net/wireless/scan.c:2555 [inline]
cfg80211_inform_bss_frame_data+0x873/0x1f30 net/wireless/scan.c:2588
ieee80211_bss_info_update+0x6c2/0xaa0 net/mac80211/scan.c:190
ieee80211_rx_bss_info net/mac80211/ibss.c:1123 [inline]
ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1614 [inline]
ieee80211_ibss_rx_queued_mgmt+0x16d0/0x29c0 net/mac80211/ibss.c:1643
ieee80211_iface_process_skb net/mac80211/iface.c:1459 [inline]
ieee80211_iface_work+0x70e/0xc60 net/mac80211/iface.c:1513
process_one_work+0x863/0x1000 kernel/workqueue.c:2310
worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Second to last potentially related work creation:
kasan_save_stack+0x35/0x60 mm/kasan/common.c:38
kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348
kvfree_call_rcu+0x10a/0x7c0 kernel/rcu/tree.c:3600
cfg80211_update_known_bss+0x178/0xa20 net/wireless/scan.c:-1
cfg80211_bss_update+0x15f/0x2250 net/wireless/scan.c:1836
cfg80211_inform_single_bss_frame_data net/wireless/scan.c:2555 [inline]
cfg80211_inform_bss_frame_data+0x873/0x1f30 net/wireless/scan.c:2588
ieee80211_bss_info_update+0x6c2/0xaa0 net/mac80211/scan.c:190
ieee80211_rx_bss_info net/mac80211/ibss.c:1123 [inline]
ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1614 [inline]
ieee80211_ibss_rx_queued_mgmt+0x16d0/0x29c0 net/mac80211/ibss.c:1643
ieee80211_iface_process_skb net/mac80211/iface.c:1459 [inline]
ieee80211_iface_work+0x70e/0xc60 net/mac80211/iface.c:1513
process_one_work+0x863/0x1000 kernel/workqueue.c:2310
worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

The buggy address belongs to the object at ffff88805f5c5d80
which belongs to the cache kmalloc-96 of size 96

The buggy address is located 0 bytes inside of

96-byte region [ffff88805f5c5d80, ffff88805f5c5de0)
The buggy address belongs to the page:
page:ffffea00017d7140 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5f5c5
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea0001cc2fc0 0000000400000004 ffff888016841780
raw: 0000000000000000 0000000000200020 00000001ffffffff 0000000000000000

page dumped because: kasan: bad access detected

page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 4196, ts 58890455901, free_ts 11292844314
prep_new_page mm/page_alloc.c:2426 [inline]
get_page_from_freelist+0x1b77/0x1c60 mm/page_alloc.c:4192
__alloc_pages+0x1e1/0x470 mm/page_alloc.c:5487
alloc_slab_page mm/slub.c:1780 [inline]
allocate_slab mm/slub.c:1917 [inline]
new_slab+0xc0/0x4b0 mm/slub.c:1980
___slab_alloc+0x81e/0xdf0 mm/slub.c:3013
__slab_alloc mm/slub.c:3100 [inline]
slab_alloc_node mm/slub.c:3191 [inline]
slab_alloc mm/slub.c:3233 [inline]
kmem_cache_alloc_trace+0x1a5/0x2a0 mm/slub.c:3250
kmalloc include/linux/slab.h:607 [inline]
dst_cow_metrics_generic+0x52/0x1b0 net/core/dst.c:202
dst_metrics_write_ptr include/net/dst.h:118 [inline]
dst_metric_set include/net/dst.h:179 [inline]
icmp6_dst_alloc+0x2d8/0x4a0 net/ipv6/route.c:3281
mld_sendpack+0x580/0xc30 net/ipv6/mcast.c:1814
mld_dad_work+0x41/0x270 net/ipv6/mcast.c:2267
process_one_work+0x863/0x1000 kernel/workqueue.c:2310
worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1340 [inline]
free_pcp_prepare mm/page_alloc.c:1391 [inline]
free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
free_unref_page+0x94/0x280 mm/page_alloc.c:3396
free_contig_range+0x96/0xf0 mm/page_alloc.c:9406
destroy_args+0x100/0xa20 mm/debug_vm_pgtable.c:1018
debug_vm_pgtable+0x318/0x370 mm/debug_vm_pgtable.c:1336
do_one_initcall+0x1ee/0x680 init/main.c:1316
do_initcall_level+0x137/0x1f0 init/main.c:1389
do_initcalls+0x4b/0x90 init/main.c:1405
kernel_init_freeable+0x3ce/0x560 init/main.c:1629
kernel_init+0x19/0x1b0 init/main.c:1520
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Memory state around the buggy address:

ffff88805f5c5c80: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
ffff88805f5c5d00: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
>ffff88805f5c5d80: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
^
ffff88805f5c5e00: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
ffff88805f5c5e80: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
==================================================================


---

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 68efe5a6c16a Linux 5.15.197
git tree: linux-5.15.y

console output: https://syzkaller.appspot.com/x/log.txt?x=113079b4580000

kernel config: https://syzkaller.appspot.com/x/.config?x=7e6ed99963d6ee1d
dashboard link: https://syzkaller.appspot.com/bug?extid=d835ed9e3eb9fb8d21ab
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1498131a580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15814d58580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/900f9b9bd850/disk-68efe5a6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1e089a5019a6/vmlinux-68efe5a6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b319f477b907/bzImage-68efe5a6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d835ed...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in dtv5100_i2c_msg+0x1db/0x2d0 drivers/media/usb/dvb-usb/dtv5100.c:58

Write of size 83 at addr ffff888025418180 by task syz.0.17/4352

CPU: 1 PID: 4352 Comm: syz.0.17 Not tainted syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
<TASK>
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
print_address_description+0x60/0x2d0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:434 [inline]
kasan_report+0xdf/0x130 mm/kasan/report.c:451
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x27b/0x290 mm/kasan/generic.c:189
memcpy+0x3c/0x60 mm/kasan/shadow.c:66
dtv5100_i2c_msg+0x1db/0x2d0 drivers/media/usb/dvb-usb/dtv5100.c:58
dtv5100_i2c_xfer+0x47c/0x650 drivers/media/usb/dvb-usb/dtv5100.c:81
__i2c_transfer+0x864/0x2060 drivers/i2c/i2c-core-base.c:-1
i2c_transfer+0x24c/0x390 drivers/i2c/i2c-core-base.c:2330
i2cdev_ioctl_rdwr+0x3da/0x6c0 drivers/i2c/i2c-dev.c:297
i2cdev_ioctl+0x5ba/0x750 drivers/i2c/i2c-dev.c:458
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0

RIP: 0033:0x7fd3219d8749

Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48

RSP: 002b:00007fff15e02238 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fd321c2efa0 RCX: 00007fd3219d8749

RDX: 00002000000002c0 RSI: 0000000000000707 RDI: 0000000000000004

RBP: 00007fd321a5cf91 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007fd321c2efa0 R14: 00007fd321c2efa0 R15: 0000000000000003
</TASK>

Allocated by task 4242:

The buggy address belongs to the object at ffff888025418180

which belongs to the cache kmalloc-96 of size 96
The buggy address is located 0 bytes inside of

96-byte region [ffff888025418180, ffff8880254181e0)

The buggy address belongs to the page:

page:ffffea0000950600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x25418

flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)

raw: 00fff00000000200 0000000000000000 dead000000000122 ffff888016841780

raw: 0000000000000000 0000000000200020 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated

page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 4245, ts 82367015242, free_ts 82158440642

free_slab mm/slub.c:2020 [inline]
discard_slab mm/slub.c:2026 [inline]
__unfreeze_partials+0x1a5/0x200 mm/slub.c:2512
put_cpu_partial+0x12d/0x190 mm/slub.c:2592
qlist_free_all+0x35/0x90 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x150/0x160 mm/kasan/quarantine.c:283
__kasan_slab_alloc+0x2f/0xd0 mm/kasan/common.c:444
kasan_slab_alloc include/linux/kasan.h:254 [inline]
slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519
slab_alloc_node mm/slub.c:3225 [inline]
kmem_cache_alloc_node+0x12d/0x2d0 mm/slub.c:3261
__alloc_skb+0xf4/0x750 net/core/skbuff.c:415
alloc_skb include/linux/skbuff.h:1162 [inline]
mld_newpack+0x12a/0xb90 net/ipv6/mcast.c:1745
add_grhead+0x5a/0x240 net/ipv6/mcast.c:1856
add_grec+0x1341/0x15d0 net/ipv6/mcast.c:1994
mld_send_initial_cr+0xed/0x240 net/ipv6/mcast.c:2241
ipv6_mc_dad_complete+0x84/0x210 net/ipv6/mcast.c:2252
addrconf_dad_completed+0x6c7/0xca0 net/ipv6/addrconf.c:4255

Memory state around the buggy address:

ffff888025418080: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
ffff888025418100: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
>ffff888025418180: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
^
ffff888025418200: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
ffff888025418280: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
==================================================================


---