[v6.1] KASAN: slab-out-of-bounds Read in copy_from_sockptr

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fb28aa725e05 Linux 6.1.180
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=119ebdb9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=872c04466179833f
dashboard link: https://syzkaller.appspot.com/bug?extid=3fe274c1ae4fad0ec84a
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d420eb944682/disk-fb28aa72.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/affae450ab23/vmlinux-fb28aa72.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b9e6919ed519/Image-fb28aa72.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3fe274...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in copy_from_sockptr_offset include/linux/sockptr.h:49 [inline]
BUG: KASAN: slab-out-of-bounds in copy_from_sockptr+0x44/0x1a8 include/linux/sockptr.h:59
Read of size 84 at addr ffff0000eea8ad00 by task syz.9.1189/8876

CPU: 0 PID: 8876 Comm: syz.9.1189 Not tainted 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
copy_from_sockptr_offset include/linux/sockptr.h:49 [inline]
copy_from_sockptr+0x44/0x1a8 include/linux/sockptr.h:59
vcc_setsockopt+0x17c/0x694 net/atm/common.c:775
pvc_setsockopt+0x84/0xb0 net/atm/pvc.c:72
__sys_setsockopt+0x2fc/0x50c net/socket.c:2288
__do_sys_setsockopt net/socket.c:2299 [inline]
__se_sys_setsockopt net/socket.c:2296 [inline]
__arm64_sys_setsockopt+0xc0/0xdc net/socket.c:2296
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x13c/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

Allocated by task 8876:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505
____kasan_kmalloc mm/kasan/common.c:375 [inline]
__kasan_kmalloc+0xa0/0xb8 mm/kasan/common.c:384
kasan_kmalloc include/linux/kasan.h:211 [inline]
__do_kmalloc_node mm/slab_common.c:936 [inline]
__kmalloc+0xd8/0x180 mm/slab_common.c:949
kmalloc include/linux/slab.h:568 [inline]
__cgroup_bpf_run_filter_setsockopt+0xa1c/0xbe0 kernel/bpf/cgroup.c:1873
__sys_setsockopt+0x4c0/0x50c net/socket.c:2271
__do_sys_setsockopt net/socket.c:2299 [inline]
__se_sys_setsockopt net/socket.c:2296 [inline]
__arm64_sys_setsockopt+0xc0/0xdc net/socket.c:2296
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x13c/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

Last potentially related work creation:
kasan_save_stack+0x40/0x70 mm/kasan/common.c:46
__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
cfg80211_update_known_bss+0x11c/0x7fc net/wireless/scan.c:-1
cfg80211_bss_update+0x150/0x1ccc net/wireless/scan.c:1847
cfg80211_inform_single_bss_frame_data net/wireless/scan.c:2509 [inline]
cfg80211_inform_bss_frame_data+0x890/0x10f8 net/wireless/scan.c:2542
ieee80211_bss_info_update+0x640/0xa7c net/mac80211/scan.c:190
ieee80211_rx_bss_info net/mac80211/ibss.c:1120 [inline]
ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1609 [inline]
ieee80211_ibss_rx_queued_mgmt+0x143c/0x2608 net/mac80211/ibss.c:1638
ieee80211_iface_process_skb net/mac80211/iface.c:1679 [inline]
ieee80211_iface_work+0x5a8/0xa4c net/mac80211/iface.c:1733
cfg80211_wiphy_work+0x1e0/0x220 net/wireless/core.c:433
process_one_work+0x7e4/0x13bc kernel/workqueue.c:2292
worker_thread+0x8cc/0xfe8 kernel/workqueue.c:2439
kthread+0x254/0x2e0 kernel/kthread.c:376
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850

The buggy address belongs to the object at ffff0000eea8ad00
which belongs to the cache kmalloc-128 of size 128
The buggy address is located 0 bytes inside of
128-byte region [ffff0000eea8ad00, ffff0000eea8ad80)

The buggy address belongs to the physical page:
page:00000000b37e070f refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12ea8a
flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000200 dead000000000100 dead000000000122 ffff0000c0002300
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff0000eea8ac00: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff0000eea8ac80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff0000eea8ad00: 00 02 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff0000eea8ad80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff0000eea8ae00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: fb28aa725e05 Linux 6.1.180
git tree: linux-6.1.y

console output: https://syzkaller.appspot.com/x/log.txt?x=16412649580000

kernel config: https://syzkaller.appspot.com/x/.config?x=872c04466179833f
dashboard link: https://syzkaller.appspot.com/bug?extid=3fe274c1ae4fad0ec84a
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: arm64

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16aa43b9580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d420eb944682/disk-fb28aa72.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/affae450ab23/vmlinux-fb28aa72.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b9e6919ed519/Image-fb28aa72.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3fe274...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in copy_from_sockptr_offset include/linux/sockptr.h:49 [inline]
BUG: KASAN: slab-out-of-bounds in copy_from_sockptr+0x44/0x1a8 include/linux/sockptr.h:59

Read of size 84 at addr ffff0000f0afe000 by task syz.0.17/4484

CPU: 0 PID: 4484 Comm: syz.0.17 Not tainted syzkaller #0

Allocated by task 4484:

kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505
____kasan_kmalloc mm/kasan/common.c:375 [inline]
__kasan_kmalloc+0xa0/0xb8 mm/kasan/common.c:384
kasan_kmalloc include/linux/kasan.h:211 [inline]
__do_kmalloc_node mm/slab_common.c:936 [inline]
__kmalloc+0xd8/0x180 mm/slab_common.c:949
kmalloc include/linux/slab.h:568 [inline]

kzalloc include/linux/slab.h:699 [inline]
sockopt_alloc_buf kernel/bpf/cgroup.c:1781 [inline]
__cgroup_bpf_run_filter_setsockopt+0x1e4/0xbe0 kernel/bpf/cgroup.c:1822

__sys_setsockopt+0x4c0/0x50c net/socket.c:2271
__do_sys_setsockopt net/socket.c:2299 [inline]
__se_sys_setsockopt net/socket.c:2296 [inline]
__arm64_sys_setsockopt+0xc0/0xdc net/socket.c:2296
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x13c/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 the object at ffff0000f0afe000

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

128-byte region [ffff0000f0afe000, ffff0000f0afe080)

The buggy address belongs to the physical page:

page:0000000006654382 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x130afe

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

raw: 05ffc00000000200 0000000000000000 dead000000000122 ffff0000c0002300

raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:

ffff0000f0afdf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff0000f0afdf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff0000f0afe000: 00 00 00 00 00 00 05 fc fc fc fc fc fc fc fc fc
^
ffff0000f0afe080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff0000f0afe100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
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