syzbot
KASAN: slab-out-of-bounds Read in pn533_recv_frame
Status:
upstream: reported C repro on 2026/10/13 09:17
Reported-by: syzbot+ffad7df43563f8084151@syzkaller.appspotmail.com
First crash: 1d10h, last: 1d00h
Sample crash report:
==================================================================
BUG: KASAN: slab-out-of-bounds in hex_dump_to_buffer+0x3b2/0xd60 lib/hexdump.c:193
Read of size 1 at addr ffff88802419c600 by task swapper/1/0
CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
<IRQ>
dump_stack_lvl+0x188/0x250 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
hex_dump_to_buffer+0x3b2/0xd60 lib/hexdump.c:193
print_hex_dump+0x168/0x2b0 lib/hexdump.c:276
pn533_recv_frame+0x593/0x5f0 drivers/nfc/pn533/pn533.c:2206
__usb_hcd_giveback_urb+0x35d/0x520 drivers/usb/core/hcd.c:1674
dummy_timer+0xa47/0x34a0 drivers/usb/gadget/udc/dummy_hcd.c:2012
call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
expire_timers kernel/time/timer.c:1699 [inline]
__run_timers+0x56c/0x810 kernel/time/timer.c:1970
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
handle_softirqs+0x336/0x830 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:730
Code: b7 48 89 df e8 76 fc f2 f7 eb ad e8 6f aa f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 00 cc 66 90 0f 00 2d f7 61 5a 00 fb f4 <c3> 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48
RSP: 0018:ffffc90000d67d48 EFLAGS: 000002c2
RAX: 09850ab72cbaef00 RBX: ffff88813fe48000 RCX: 09850ab72cbaef00
RDX: 0000000000000001 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4c00
RBP: ffffc90000d67e80 R08: ffff8880b8f3b30b R09: 1ffff110171e7661
R10: dffffc0000000000 R11: ffffed10171e7662 R12: 1ffff920001acfb4
R13: dffffc0000000000 R14: 1ffff11027fc9000 R15: 0000000000000000
default_idle_call+0x81/0xc0 kernel/sched/idle.c:112
cpuidle_idle_call kernel/sched/idle.c:202 [inline]
do_idle+0x3a1/0x650 kernel/sched/idle.c:326
cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:424
start_secondary+0x32f/0x430 arch/x86/kernel/smpboot.c:281
secondary_startup_64_no_verify+0xb1/0xbb
</TASK>
Allocated by task 0:
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+0xaf/0xe0 mm/kasan/common.c:522
kmalloc_reserve net/core/skbuff.c:356 [inline]
__alloc_skb+0x22c/0x750 net/core/skbuff.c:427
alloc_skb include/linux/skbuff.h:1162 [inline]
pn533_recv_response+0xbc/0x230 drivers/nfc/pn533/usb.c:65
__usb_hcd_giveback_urb+0x35d/0x520 drivers/usb/core/hcd.c:1674
dummy_timer+0xa47/0x34a0 drivers/usb/gadget/udc/dummy_hcd.c:2012
call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
expire_timers kernel/time/timer.c:1699 [inline]
__run_timers+0x56c/0x810 kernel/time/timer.c:1970
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
handle_softirqs+0x336/0x830 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
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
__call_rcu kernel/rcu/tree.c:3011 [inline]
call_rcu+0x189/0x900 kernel/rcu/tree.c:3091
percpu_ref_put_many include/linux/percpu-refcount.h:322 [inline]
percpu_ref_put+0x1f6/0x200 include/linux/percpu-refcount.h:338
rcu_do_batch kernel/rcu/tree.c:2523 [inline]
rcu_core+0x96e/0x1650 kernel/rcu/tree.c:2763
handle_softirqs+0x336/0x830 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
The buggy address belongs to the object at ffff88802419c400
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 0 bytes to the right of
512-byte region [ffff88802419c400, ffff88802419c600)
The buggy address belongs to the page:
page:ffffea0000906700 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2419c
head:ffffea0000906700 order:2 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea0000a06000 0000000200000002 ffff888017841c80
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
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 1399, ts 10339001800, free_ts 0
prep_new_page mm/page_alloc.c:2426 [inline]
get_page_from_freelist+0x24f6/0x2670 mm/page_alloc.c:4192
__alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
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+0x807/0xdd0 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+0xf9/0x290 mm/slub.c:3250
kmalloc include/linux/slab.h:607 [inline]
kzalloc include/linux/slab.h:738 [inline]
alloc_bprm+0x56/0x690 fs/exec.c:1522
kernel_execve+0x49/0x8e0 fs/exec.c:1984
call_usermodehelper_exec_async+0x207/0x350 kernel/umh.c:112
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
page_owner free stack trace missing
Memory state around the buggy address:
ffff88802419c500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88802419c580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88802419c600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff88802419c680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802419c700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
----------------
Code disassembly (best guess):
0: b7 48 mov $0x48,%bh
2: 89 df mov %ebx,%edi
4: e8 76 fc f2 f7 call 0xf7f2fc7f
9: eb ad jmp 0xffffffb8
b: e8 6f aa f6 ff call 0xfff6aa7f
10: 00 00 add %al,(%rax)
12: cc int3
13: cc int3
14: 00 00 add %al,(%rax)
16: cc int3
17: cc int3
18: 00 00 add %al,(%rax)
1a: cc int3
1b: cc int3
1c: 00 00 add %al,(%rax)
1e: cc int3
1f: 66 90 xchg %ax,%ax
21: 0f 00 2d f7 61 5a 00 verw 0x5a61f7(%rip) # 0x5a621f
28: fb sti
29: f4 hlt
* 2a: c3 ret <-- trapping instruction
2b: 0f 1f 40 00 nopl 0x0(%rax)
2f: 41 57 push %r15
31: 41 56 push %r14
33: 53 push %rbx
34: 49 be 00 00 00 00 00 movabs $0xdffffc0000000000,%r14
3b: fc ff df
3e: 65 gs
3f: 48 rex.W
Struck through repros no longer work on HEAD.