From: syzbot <syzbot+93f169a8e7d66864f800@syzkaller.appspotmail.com>
To: chandradhar.2003@gmail.com, david@ixit.cz, krzk@kernel.org,
linux-kernel@vger.kernel.org, michael.thalmeier@hale.at,
netdev@vger.kernel.org, oe-linux-nfc@lists.linux.dev,
sameo@linux.intel.com, shreeramrahul94@gmail.com,
syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [nfc?] KASAN: slab-out-of-bounds Read in pn533_recv_frame
Date: Thu, 05 Nov 2026 00:23:46 -0800 [thread overview]
Message-ID: <6aec3d12.f31022ea.233d2f.0004.GAE@google.com> (raw)
In-Reply-To: <6acd1c88.a150a118.27e199.0053.GAE@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: 8b7179210b22 Add linux-next specific files for 20261104
git tree: linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1472fca1580000
kernel config: https://syzkaller.appspot.com/x/.config?x=5dad87d6a9d5ee90
dashboard link: https://syzkaller.appspot.com/bug?extid=93f169a8e7d66864f800
compiler: Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1641aca1580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15c09edd580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/24dabb992a55/disk-8b717921.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/efb6c59219d5/vmlinux-8b717921.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ced4d906c236/bzImage-8b717921.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+93f169a8e7d66864f800@syzkaller.appspotmail.com
PN533 RX: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
PN533 RX: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
PN533 RX: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
PN533 RX: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
BUG: KASAN: slab-out-of-bounds in hex_dump_to_buffer+0x36c/0xd70 lib/hexdump.c:194
Read of size 1 at addr ffff888027737a00 by task swapper/1/0
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
<IRQ>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description+0x55/0x1e0 mm/kasan/report.c:378
print_report+0x58/0x70 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
hex_dump_to_buffer+0x36c/0xd70 lib/hexdump.c:194
print_hex_dump+0x16b/0x2b0 lib/hexdump.c:277
pn533_recv_frame+0x5f6/0x6d0 drivers/nfc/pn533/pn533.c:2202
__usb_hcd_giveback_urb+0x378/0x540 drivers/usb/core/hcd.c:1658
dummy_timer+0xa9a/0x4ce0 drivers/usb/gadget/udc/dummy_hcd.c:2051
__run_hrtimer kernel/time/hrtimer.c:2079 [inline]
__hrtimer_run_queues+0x3bc/0xa10 kernel/time/hrtimer.c:2136
hrtimer_run_softirq+0x1e3/0x2e0 kernel/time/hrtimer.c:2153
handle_softirqs+0x265/0x8d0 kernel/softirq.c:669
__do_softirq kernel/softirq.c:703 [inline]
invoke_softirq kernel/softirq.c:542 [inline]
__irq_exit_rcu+0xc6/0x220 kernel/softirq.c:786
irq_exit_rcu+0x9/0x30 kernel/softirq.c:809
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1073 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1073
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:finish_task_switch+0x413/0xc60 kernel/sched/core.c:5434
Code: 04 00 00 41 c7 84 24 20 0e 00 00 00 00 00 00 0f 1f 44 00 00 49 83 c4 48 4c 89 e7 e8 c7 56 89 0a e8 22 92 3a 00 fb 4c 8b 65 c8 <49> 8d bc 24 18 17 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0
RSP: 0018:ffffc900001c7be0 EFLAGS: 00000206
RAX: 000000000008812b RBX: ffff8880b833d3a0 RCX: 8000000000000001
RDX: 0000000000000000 RSI: ffffffff8e9ef560 RDI: ffffffff8cb01080
RBP: ffffc900001c7c30 R08: ffffffff91e104bf R09: 1ffffffff23c2097
R10: dffffc0000000000 R11: fffffbfff23c2098 R12: ffff88801fa99f40
R13: ffff88801fa99f40 R14: dffffc0000000000 R15: 1ffff11017067a74
context_switch kernel/sched/core.c:5586 [inline]
__schedule+0x17e5/0x5830 kernel/sched/core.c:7382
schedule_idle+0x51/0x90 kernel/sched/core.c:7500
do_idle+0x4ad/0x540 kernel/sched/idle.c:384
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:458
start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
common_startup_64+0x13e/0x157
</TASK>
Allocated by task 0:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3f/0x90 mm/kasan/common.c:79
unpoison_slab_object mm/kasan/common.c:354 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:380
kasan_slab_alloc include/linux/kasan.h:257 [inline]
slab_post_alloc_hook mm/slub.c:4716 [inline]
slab_alloc_node mm/slub.c:5029 [inline]
kmem_cache_alloc_node_noprof+0x34f/0x600 mm/slub.c:5101
kmalloc_reserve net/core/skbuff.c:616 [inline]
__alloc_skb+0x27a/0x7a0 net/core/skbuff.c:716
alloc_skb include/linux/skbuff.h:1390 [inline]
pn533_recv_response+0xc4/0x230 drivers/nfc/pn533/usb.c:65
__usb_hcd_giveback_urb+0x378/0x540 drivers/usb/core/hcd.c:1658
dummy_timer+0xa9a/0x4ce0 drivers/usb/gadget/udc/dummy_hcd.c:2051
__run_hrtimer kernel/time/hrtimer.c:2079 [inline]
__hrtimer_run_queues+0x3bc/0xa10 kernel/time/hrtimer.c:2136
hrtimer_run_softirq+0x1e3/0x2e0 kernel/time/hrtimer.c:2153
handle_softirqs+0x265/0x8d0 kernel/softirq.c:669
__do_softirq kernel/softirq.c:703 [inline]
invoke_softirq kernel/softirq.c:542 [inline]
__irq_exit_rcu+0xc6/0x220 kernel/softirq.c:786
irq_exit_rcu+0x9/0x30 kernel/softirq.c:809
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1073 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1073
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
The buggy address belongs to the object at ffff888027737740
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 [ffff888027737740, ffff888027737a00)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x27734
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 ffff888140a9bdc0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000200130013 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff888140a9bdc0 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5650, tgid 5650 (syz-executor223), ts 84263979260
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1874
prep_new_page+0x22/0xb0 mm/page_alloc.c:1882
get_page_from_freelist+0x22a1/0x22e0 mm/page_alloc.c:3964
__alloc_frozen_pages_noprof+0x211/0x450 mm/page_alloc.c:5506
alloc_slab_page mm/slub.c:3382 [inline]
allocate_slab+0x7d/0x5e0 mm/slub.c:3497
new_slab mm/slub.c:3548 [inline]
refill_objects+0x2d5/0x350 mm/slub.c:7522
refill_sheaf mm/slub.c:2915 [inline]
__pcs_replace_empty_main+0x2c8/0x6c0 mm/slub.c:4807
alloc_from_pcs mm/slub.c:4883 [inline]
slab_alloc_node mm/slub.c:5017 [inline]
kmem_cache_alloc_node_noprof+0x432/0x600 mm/slub.c:5101
kmalloc_reserve net/core/skbuff.c:616 [inline]
__alloc_skb+0x27a/0x7a0 net/core/skbuff.c:716
napi_alloc_skb+0x86/0xaf0 net/core/skbuff.c:856
page_to_skb+0x240/0x1780 drivers/net/virtio_net.c:880
receive_mergeable drivers/net/virtio_net.c:2426 [inline]
receive_buf+0x720/0x1b60 drivers/net/virtio_net.c:2596
virtnet_receive_packets drivers/net/virtio_net.c:2921 [inline]
virtnet_receive drivers/net/virtio_net.c:2945 [inline]
virtnet_poll+0x22bf/0x3100 drivers/net/virtio_net.c:3040
__napi_poll+0xaa/0x330 net/core/dev.c:7985
napi_poll net/core/dev.c:8048 [inline]
net_rx_action+0x61d/0xf50 net/core/dev.c:8205
handle_softirqs+0x265/0x8d0 kernel/softirq.c:669
page last free pid 5317 tgid 5317 ts 54559667751 stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
__free_pages_prepare mm/page_alloc.c:1416 [inline]
__free_frozen_pages+0xd1a/0xe10 mm/page_alloc.c:2972
__slab_free+0x269/0x2c0 mm/slub.c:5922
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:364
kasan_slab_alloc include/linux/kasan.h:257 [inline]
slab_post_alloc_hook mm/slub.c:4716 [inline]
slab_alloc_node mm/slub.c:5029 [inline]
kmem_cache_alloc_noprof+0x2b4/0x600 mm/slub.c:5043
vm_area_alloc+0x24/0x140 mm/vma_init.c:36
__mmap_new_vma mm/vma.c:2765 [inline]
__mmap_region mm/vma.c:3119 [inline]
mmap_region+0x18e8/0x2820 mm/vma.c:3201
do_mmap+0xe0a/0x1300 mm/mmap.c:573
vm_mmap_pgoff+0x27a/0x520 mm/util.c:581
ksys_mmap_pgoff+0x4dc/0x760 mm/mmap.c:619
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x16a/0x530 arch/x86/entry/syscall_64.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Memory state around the buggy address:
ffff888027737900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff888027737980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888027737a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff888027737a80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888027737b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 00 00 add %al,(%rax)
2: 41 c7 84 24 20 0e 00 movl $0x0,0xe20(%r12)
9: 00 00 00 00 00
e: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
13: 49 83 c4 48 add $0x48,%r12
17: 4c 89 e7 mov %r12,%rdi
1a: e8 c7 56 89 0a call 0xa8956e6
1f: e8 22 92 3a 00 call 0x3a9246
24: fb sti
25: 4c 8b 65 c8 mov -0x38(%rbp),%r12
* 29: 49 8d bc 24 18 17 00 lea 0x1718(%r12),%rdi <-- trapping instruction
30: 00
31: 48 89 f8 mov %rdi,%rax
34: 48 c1 e8 03 shr $0x3,%rax
38: 42 0f b6 04 30 movzbl (%rax,%r14,1),%eax
3d: 84 c0 test %al,%al
---
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.
prev parent reply other threads:[~2026-11-05 8:23 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-12 17:44 syzbot
2026-11-05 8:23 ` syzbot [this message]
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