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BUG: KASAN: slab-use-after-free in rose_get_neigh+0x549/0x640 net/rose/rose_route.c:692
Read of size 1 at addr ffff888034a9f030 by task syz.1.1361/9841

CPU: 1 UID: 0 PID: 9841 Comm: syz.1.1361 Not tainted 6.15.0-rc4-syzkaller-00296-ge8ab83e34bdc #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc3/0x670 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 rose_get_neigh+0x549/0x640 net/rose/rose_route.c:692
 rose_connect+0x2d4/0x1540 net/rose/af_rose.c:816
 __sys_connect_file+0x13e/0x1a0 net/socket.c:2038
 __sys_connect+0x14d/0x170 net/socket.c:2057
 __do_sys_connect net/socket.c:2063 [inline]
 __se_sys_connect net/socket.c:2060 [inline]
 __x64_sys_connect+0x72/0xb0 net/socket.c:2060
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3ce778e969
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3ce8573038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f3ce79b5fa0 RCX: 00007f3ce778e969
RDX: 000000000000001c RSI: 0000200000000040 RDI: 0000000000000008
RBP: 00007f3ce7810ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f3ce79b5fa0 R15: 00007ffdb425d1b8
 </TASK>

Allocated by task 8100:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kmalloc_noprof include/linux/slab.h:905 [inline]
 rose_add_node net/rose/rose_route.c:85 [inline]
 rose_rt_ioctl+0x87e/0x1d40 net/rose/rose_route.c:747
 rose_ioctl+0x64d/0x7d0 net/rose/af_rose.c:1380
 sock_do_ioctl+0x115/0x280 net/socket.c:1190
 sock_ioctl+0x227/0x6b0 net/socket.c:1311
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl fs/ioctl.c:892 [inline]
 __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 9841:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2380 [inline]
 slab_free mm/slub.c:4642 [inline]
 kfree+0x2b6/0x4d0 mm/slub.c:4841
 rose_remove_neigh+0x25e/0x370 net/rose/rose_route.c:240
 rose_rt_device_down+0x2aa/0x390 net/rose/rose_route.c:522
 rose_device_event+0xfc/0x120 net/rose/af_rose.c:248
 notifier_call_chain+0xb9/0x410 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2176
 call_netdevice_notifiers_extack net/core/dev.c:2214 [inline]
 call_netdevice_notifiers net/core/dev.c:2228 [inline]
 __dev_notify_flags+0x1f7/0x2e0 net/core/dev.c:9407
 netif_change_flags+0x108/0x160 net/core/dev.c:9434
 dev_change_flags+0xba/0x250 net/core/dev_api.c:68
 dev_ifsioc+0x1498/0x1f70 net/core/dev_ioctl.c:565
 dev_ioctl+0x223/0x10e0 net/core/dev_ioctl.c:821
 sock_do_ioctl+0x19d/0x280 net/socket.c:1204
 sock_ioctl+0x227/0x6b0 net/socket.c:1311
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl fs/ioctl.c:892 [inline]
 __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888034a9f000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 48 bytes inside of
 freed 512-byte region [ffff888034a9f000, ffff888034a9f200)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x34a9c
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 ffff88801b441c80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801b441c80 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0000d2a701 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 1, tgid 1 (swapper/0), ts 13045045600, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1718
 prep_new_page mm/page_alloc.c:1726 [inline]
 get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3688
 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4970
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2450 [inline]
 allocate_slab mm/slub.c:2618 [inline]
 new_slab+0x244/0x340 mm/slub.c:2672
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3858
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3948
 __slab_alloc_node mm/slub.c:4023 [inline]
 slab_alloc_node mm/slub.c:4184 [inline]
 __do_kmalloc_node mm/slub.c:4326 [inline]
 __kmalloc_node_track_caller_noprof+0x2ee/0x510 mm/slub.c:4346
 __do_krealloc mm/slub.c:4904 [inline]
 krealloc_noprof+0x157/0x380 mm/slub.c:4957
 add_sysfs_param+0xd3/0xa00 kernel/params.c:654
 kernel_add_sysfs_param kernel/params.c:811 [inline]
 param_sysfs_builtin kernel/params.c:850 [inline]
 param_sysfs_builtin_init+0x307/0x4c0 kernel/params.c:984
 do_one_initcall+0x120/0x6e0 init/main.c:1257
 do_initcall_level init/main.c:1319 [inline]
 do_initcalls init/main.c:1335 [inline]
 do_basic_setup init/main.c:1354 [inline]
 kernel_init_freeable+0x5c2/0x900 init/main.c:1567
 kernel_init+0x1c/0x2b0 init/main.c:1457
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888034a9ef00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888034a9ef80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888034a9f000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff888034a9f080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888034a9f100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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