[v6.1] KASAN: use-after-free Read in rose_send_frame

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 882efbdd9d34 Linux 6.1.155
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=160d585b980000
kernel config: https://syzkaller.appspot.com/x/.config?x=7eb38bd5021fec61
dashboard link: https://syzkaller.appspot.com/bug?extid=eeab790effbfe2b4065c
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/23ee6a61dc15/disk-882efbdd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0bb5f10b3f6e/vmlinux-882efbdd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/64776e288bcc/bzImage-882efbdd.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+eeab79...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in rose_send_frame+0x73/0x220 net/rose/rose_link.c:101
Read of size 8 at addr ffff888055f99420 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 08/18/2025
Call Trace:
<IRQ>
dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
print_address_description mm/kasan/report.c:316 [inline]
print_report+0xa8/0x210 mm/kasan/report.c:420
kasan_report+0x10b/0x140 mm/kasan/report.c:524
rose_send_frame+0x73/0x220 net/rose/rose_link.c:101
rose_transmit_restart_request net/rose/rose_link.c:198 [inline]
rose_t0timer_expiry+0x13f/0x350 net/rose/rose_link.c:83
call_timer_fn+0x1a0/0x670 kernel/time/timer.c:1504
expire_timers kernel/time/timer.c:1549 [inline]
__run_timers+0x525/0x7c0 kernel/time/timer.c:1820
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833
handle_softirqs+0x2a1/0x920 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x12f/0x220 kernel/softirq.c:679
irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:742
Code: 48 89 df e8 87 71 af f7 e9 4c ff ff ff e8 ad 07 f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 66 90 0f 00 2d 37 13 65 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:ffffc90000177de8 EFLAGS: 000002c6
RAX: 766a3d05d892a700 RBX: ffffffff8a218f77 RCX: 766a3d05d892a700
RDX: 0000000000000001 RSI: ffffffff8a8c0500 RDI: ffffffff8adefd20
RBP: ffffc90000177f20 R08: dffffc0000000000 R09: ffffed10171e6afa
R10: ffffed10171e6afa R11: 1ffff110171e6af9 R12: 0000000000000001
R13: dffffc0000000000 R14: ffff888017739dc0 R15: 1ffffffff1c3ecf6
default_idle_call+0x84/0xc0 kernel/sched/idle.c:109
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x1fc/0x570 kernel/sched/idle.c:303
cpu_startup_entry+0x3f/0x60 kernel/sched/idle.c:401
start_secondary+0xe4/0xf0 arch/x86/kernel/smpboot.c:281
secondary_startup_64_no_verify+0xcf/0xdb
</TASK>

Allocated by task 5899:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
____kasan_kmalloc mm/kasan/common.c:374 [inline]
__kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:383
kmalloc include/linux/slab.h:563 [inline]
rose_add_node+0x227/0xe80 net/rose/rose_route.c:85
rose_rt_ioctl+0xb13/0xf20 net/rose/rose_route.c:748
rose_ioctl+0x27a/0x790 net/rose/af_rose.c:1381
sock_do_ioctl+0xd3/0x2f0 net/socket.c:1204
sock_ioctl+0x4ed/0x6e0 net/socket.c:1321
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

Freed by task 15:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
kasan_save_free_info+0x2d/0x50 mm/kasan/generic.c:516
____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
kasan_slab_free include/linux/kasan.h:177 [inline]
slab_free_hook mm/slub.c:1729 [inline]
slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1755
slab_free mm/slub.c:3687 [inline]
__kmem_cache_free+0xb6/0x1f0 mm/slub.c:3700
rose_neigh_put include/net/rose.h:166 [inline]
rose_timer_expiry+0x4a7/0x5d0 net/rose/rose_timer.c:183
call_timer_fn+0x1a0/0x670 kernel/time/timer.c:1504
expire_timers kernel/time/timer.c:1549 [inline]
__run_timers+0x525/0x7c0 kernel/time/timer.c:1820
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833
handle_softirqs+0x2a1/0x920 kernel/softirq.c:596
run_ksoftirqd+0x98/0xf0 kernel/softirq.c:963
smpboot_thread_fn+0x64a/0xa40 kernel/smpboot.c:164
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

The buggy address belongs to the object at ffff888055f99400
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 32 bytes inside of
512-byte region [ffff888055f99400, ffff888055f99600)

The buggy address belongs to the physical page:
page:ffffea000157e600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x55f98
head:ffffea000157e600 order:2 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888017441c80
raw: 0000000000000000 0000000000100010 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 0x52a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 4268, tgid 4268 (syz-executor), ts 77408886606, free_ts 21956785306
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2532
prep_new_page mm/page_alloc.c:2539 [inline]
get_page_from_freelist+0x1a26/0x1ac0 mm/page_alloc.c:4328
__alloc_pages+0x1df/0x4e0 mm/page_alloc.c:5614
alloc_slab_page+0x5d/0x160 mm/slub.c:1799
allocate_slab mm/slub.c:1944 [inline]
new_slab+0x87/0x2c0 mm/slub.c:1997
___slab_alloc+0xbc6/0x1230 mm/slub.c:3154
__slab_alloc mm/slub.c:3240 [inline]
slab_alloc_node mm/slub.c:3325 [inline]
__kmem_cache_alloc_node+0x1a0/0x260 mm/slub.c:3398
__do_kmalloc_node mm/slab_common.c:935 [inline]
__kmalloc+0xa0/0x240 mm/slab_common.c:949
kmalloc include/linux/slab.h:568 [inline]
kzalloc include/linux/slab.h:699 [inline]
fib6_info_alloc+0x2e/0xe0 net/ipv6/ip6_fib.c:156
ip6_route_info_create+0x44f/0x1210 net/ipv6/route.c:3794
addrconf_f6i_alloc+0x1b9/0x3f0 net/ipv6/route.c:4621
fixup_permanent_addr net/ipv6/addrconf.c:3528 [inline]
addrconf_permanent_addr+0x26e/0x980 net/ipv6/addrconf.c:3567
addrconf_notify+0x986/0xf40 net/ipv6/addrconf.c:3639
notifier_call_chain kernel/notifier.c:87 [inline]
raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:455
call_netdevice_notifiers_extack net/core/dev.c:2039 [inline]
call_netdevice_notifiers net/core/dev.c:2053 [inline]
__dev_notify_flags+0x178/0x2d0 net/core/dev.c:-1
dev_change_flags+0xe3/0x1a0 net/core/dev.c:8714
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1459 [inline]
free_pcp_prepare mm/page_alloc.c:1509 [inline]
free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3384
free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3479
free_contig_range+0x9d/0x150 mm/page_alloc.c:9574
destroy_args+0x100/0xa31 mm/debug_vm_pgtable.c:1031
debug_vm_pgtable+0x32a/0x37e mm/debug_vm_pgtable.c:1359
do_one_initcall+0x214/0x7a0 init/main.c:1298
do_initcall_level+0x137/0x1e4 init/main.c:1371
do_initcalls+0x4b/0x8a init/main.c:1387
kernel_init_freeable+0x3fa/0x5ac init/main.c:1626
kernel_init+0x19/0x1b0 init/main.c:1514
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Memory state around the buggy address:
ffff888055f99300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888055f99380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888055f99400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888055f99480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888055f99500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: 48 89 df mov %rbx,%rdi
3: e8 87 71 af f7 call 0xf7af718f
8: e9 4c ff ff ff jmp 0xffffff59
d: e8 ad 07 f6 ff call 0xfff607bf
12: 00 00 add %al,(%rax)
14: cc int3
15: cc int3
16: 00 00 add %al,(%rax)
18: cc int3
19: cc int3
1a: 00 00 add %al,(%rax)
1c: cc int3
1d: cc int3
1e: 00 66 90 add %ah,-0x70(%rsi)
21: 0f 00 2d 37 13 65 00 verw 0x651337(%rip) # 0x65135f
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


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