syzbot
KASAN: slab-out-of-bounds Read in pn533_recv_frame
Status:
upstream: reported on 2026/10/12 17:44
Subsystems:
nfc
Labels:
prio:high
[Documentation on labels]
Reported-by: syzbot+93f169a8e7d66864f800@syzkaller.appspotmail.com
First crash: 6d20h, last: 22h13m
Sample crash report:
=========
==================================================================
BUG: KASAN: slab-out-of-bounds in hex_dump_to_buffer+0xbc4/0xc60 lib/hexdump.c:194
Read of size 1 at addr ffff888055a45640 by task kworker/1:1H/2093
CPU: 1 UID: 0 PID: 2093 Comm: kworker/1:1H Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026
Workqueue: events_highpri snd_vmidi_output_work
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x13d/0x4b0 mm/kasan/report.c:482
kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
hex_dump_to_buffer+0xbc4/0xc60 lib/hexdump.c:194
print_hex_dump+0x14a/0x1f0 lib/hexdump.c:277
pn533_recv_frame+0x48e/0x6d0 drivers/nfc/pn533/pn533.c:2202
__usb_hcd_giveback_urb+0x38e/0x610 drivers/usb/core/hcd.c:1657
usb_hcd_giveback_urb+0x3ca/0x4a0 drivers/usb/core/hcd.c:1741
dummy_timer+0xdaf/0x3820 drivers/usb/gadget/udc/dummy_hcd.c:2023
__run_hrtimer kernel/time/hrtimer.c:2074 [inline]
__hrtimer_run_queues+0x462/0x9c0 kernel/time/hrtimer.c:2131
hrtimer_run_softirq+0x1ca/0x360 kernel/time/hrtimer.c:2148
handle_softirqs+0x1e6/0x9d0 kernel/softirq.c:645
__do_softirq kernel/softirq.c:679 [inline]
invoke_softirq kernel/softirq.c:519 [inline]
__irq_exit_rcu+0x16a/0x210 kernel/softirq.c:758
irq_exit_rcu+0x9/0x30 kernel/softirq.c:775
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:finish_task_switch.isra.0+0x2ca/0x10d0 kernel/sched/core.c:5384
Code: b6 0a 00 00 41 c7 87 20 0e 00 00 00 00 00 00 e9 47 04 00 00 49 8d 7f 48 e8 b3 fe ff 09 e8 1e 42 3d 00 fb 48 8d bb 18 17 00 00 <48> b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 04 02 84
RSP: 0018:ffffc9000707f8d8 EFLAGS: 00000202
RAX: 0000000003e2065d RBX: ffff88802e538000 RCX: 0000000000000040
RDX: 0000000000000001 RSI: ffffffff8e3e346f RDI: ffff88802e539718
RBP: ffffc9000707f930 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff88808d78a580
R13: 0000000000000001 R14: ffffffff92459904 R15: ffff8880b833bf00
context_switch kernel/sched/core.c:5536 [inline]
__schedule+0x1261/0x6920 kernel/sched/core.c:7284
preempt_schedule_common+0x3c/0xb0 kernel/sched/core.c:7463
preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:211 [inline]
_raw_spin_unlock_irqrestore+0x61/0x80 kernel/locking/spinlock.c:221
spin_unlock_irqrestore include/linux/spinlock.h:425 [inline]
class_spinlock_irqsave_destructor include/linux/spinlock.h:642 [inline]
snd_rawmidi_transmit+0xf1/0x130 sound/core/rawmidi.c:1489
snd_vmidi_output_work+0x111/0x390 sound/core/seq/seq_virmidi.c:152
process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396
process_scheduled_works kernel/workqueue.c:3479 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Allocated by task 2093:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
unpoison_slab_object mm/kasan/common.c:351 [inline]
__kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:377
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4683 [inline]
slab_alloc_node mm/slub.c:4996 [inline]
kmem_cache_alloc_node_noprof+0x282/0x6e0 mm/slub.c:5068
kmalloc_reserve+0x148/0x350 net/core/skbuff.c:615
__alloc_skb+0x185/0x710 net/core/skbuff.c:715
alloc_skb include/linux/skbuff.h:1384 [inline]
pn533_recv_response+0x100/0x200 drivers/nfc/pn533/usb.c:65
__usb_hcd_giveback_urb+0x38e/0x610 drivers/usb/core/hcd.c:1657
usb_hcd_giveback_urb+0x3ca/0x4a0 drivers/usb/core/hcd.c:1741
dummy_timer+0xdaf/0x3820 drivers/usb/gadget/udc/dummy_hcd.c:2023
__run_hrtimer kernel/time/hrtimer.c:2074 [inline]
__hrtimer_run_queues+0x462/0x9c0 kernel/time/hrtimer.c:2131
hrtimer_run_softirq+0x1ca/0x360 kernel/time/hrtimer.c:2148
handle_softirqs+0x1e6/0x9d0 kernel/softirq.c:645
__do_softirq kernel/softirq.c:679 [inline]
invoke_softirq kernel/softirq.c:519 [inline]
__irq_exit_rcu+0x16a/0x210 kernel/softirq.c:758
irq_exit_rcu+0x9/0x30 kernel/softirq.c:775
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
The buggy address belongs to the object at ffff888055a45380
which belongs to the cache skbuff_small_head of size 704
The buggy address is located 0 bytes to the right of
allocated 704-byte region [ffff888055a45380, ffff888055a45640)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x55a44
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff888021ae8b40 dead000000000100 dead000000000122
raw: 0000000000000000 0000000200130013 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff888021ae8b40 dead000000000100 dead000000000122
head: 0000000000000000 0000000200130013 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffffffffffff01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 16404, tgid 16404 (syz-executor), ts 1143707632772
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871
prep_new_page mm/page_alloc.c:1879 [inline]
get_page_from_freelist+0x110d/0x35d0 mm/page_alloc.c:3943
__alloc_frozen_pages_noprof+0x2eb/0x3300 mm/page_alloc.c:5436
alloc_slab_page mm/slub.c:3347 [inline]
allocate_slab mm/slub.c:3462 [inline]
new_slab+0xa9/0x6e0 mm/slub.c:3513
refill_objects+0xe3/0x410 mm/slub.c:7418
refill_sheaf mm/slub.c:2885 [inline]
__pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4774
alloc_from_pcs mm/slub.c:4850 [inline]
slab_alloc_node mm/slub.c:4984 [inline]
kmem_cache_alloc_node_noprof+0x4f2/0x6e0 mm/slub.c:5068
kmalloc_reserve+0x148/0x350 net/core/skbuff.c:615
__alloc_skb+0x185/0x710 net/core/skbuff.c:715
alloc_skb include/linux/skbuff.h:1384 [inline]
netlink_alloc_large_skb+0x69/0x150 net/netlink/af_netlink.c:1204
netlink_sendmsg+0x680/0xda0 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:800 [inline]
__sock_sendmsg net/socket.c:815 [inline]
__sys_sendto+0x48b/0x4e0 net/socket.c:2281
__do_sys_sendto net/socket.c:2288 [inline]
__se_sys_sendto net/socket.c:2284 [inline]
__x64_sys_sendto+0xe0/0x1c0 net/socket.c:2284
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 15280 tgid 15280 ts 1031381640257 stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
__free_pages_prepare mm/page_alloc.c:1418 [inline]
__free_frozen_pages+0x79f/0x10f0 mm/page_alloc.c:2962
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:361
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4683 [inline]
slab_alloc_node mm/slub.c:4996 [inline]
kmem_cache_alloc_noprof+0x269/0x6a0 mm/slub.c:5010
new_handle fs/jbd2/transaction.c:457 [inline]
jbd2__journal_start+0x194/0x6b0 fs/jbd2/transaction.c:485
__ext4_journal_start_sb+0x314/0x610 fs/ext4/ext4_jbd2.c:122
__ext4_journal_start fs/ext4/ext4_jbd2.h:238 [inline]
ext4_dirty_inode+0xa1/0x130 fs/ext4/inode.c:6733
__mark_inode_dirty+0x1f3/0x16e0 fs/fs-writeback.c:2744
generic_update_time fs/inode.c:2252 [inline]
file_update_time_flags+0x49c/0x520 fs/inode.c:2482
ext4_page_mkwrite+0x324/0x1860 fs/ext4/inode.c:6902
do_page_mkwrite+0x17a/0x440 mm/memory.c:3816
do_shared_fault mm/memory.c:6076 [inline]
do_fault+0x659/0x1830 mm/memory.c:6138
do_pte_missing mm/memory.c:4700 [inline]
handle_pte_fault mm/memory.c:6558 [inline]
__handle_mm_fault+0x150b/0x2f60 mm/memory.c:6707
handle_mm_fault+0x363/0xa20 mm/memory.c:6876
do_user_addr_fault+0x59c/0x12f0 arch/x86/mm/fault.c:1343
Memory state around the buggy address:
ffff888055a45500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff888055a45580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888055a45600: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
^
ffff888055a45680: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
ffff888055a45700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: b6 0a mov $0xa,%dh
2: 00 00 add %al,(%rax)
4: 41 c7 87 20 0e 00 00 movl $0x0,0xe20(%r15)
b: 00 00 00 00
f: e9 47 04 00 00 jmp 0x45b
14: 49 8d 7f 48 lea 0x48(%r15),%rdi
18: e8 b3 fe ff 09 call 0x9fffed0
1d: e8 1e 42 3d 00 call 0x3d4240
22: fb sti
23: 48 8d bb 18 17 00 00 lea 0x1718(%rbx),%rdi
* 2a: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax <-- trapping instruction
31: fc ff df
34: 48 89 fa mov %rdi,%rdx
37: 48 c1 ea 03 shr $0x3,%rdx
3b: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax
3f: 84 .byte 0x84
Struck through repros no longer work on HEAD.