syzbot

==================================================================
BUG: KASAN: slab-use-after-free in rose_timer_expiry+0x45a/0x4d0 net/rose/rose_timer.c:183
Read of size 2 at addr ffff888033fbf02a by task syz.8.3526/21001

CPU: 1 UID: 0 PID: 21001 Comm: syz.8.3526 Not tainted 6.16.0-rc2-syzkaller-00047-g52da431bf03b #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <IRQ>
 __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+0xcd/0x680 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 rose_timer_expiry+0x45a/0x4d0 net/rose/rose_timer.c:183
 call_timer_fn+0x19a/0x620 kernel/time/timer.c:1747
 expire_timers kernel/time/timer.c:1798 [inline]
 __run_timers+0x6ef/0x960 kernel/time/timer.c:2372
 __run_timer_base kernel/time/timer.c:2384 [inline]
 __run_timer_base kernel/time/timer.c:2376 [inline]
 run_timer_base+0x114/0x190 kernel/time/timer.c:2393
 run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2403
 handle_softirqs+0x219/0x8e0 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0x109/0x170 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__copy_msghdr+0x321/0x470 net/socket.c:2456
Code: 45 31 e4 e8 01 ad 6f f8 44 89 e0 5b 5d 41 5c 41 5d e9 be d2 c3 f7 e8 ee ac 6f f8 c7 43 08 00 00 00 00 45 31 e4 e8 df ac 6f f8 <44> 89 63 08 4d 85 ed 0f 85 c1 fe ff ff e8 cd ac 6f f8 4c 8b 6d 00
RSP: 0018:ffffc9000a6ffa60 EFLAGS: 00000246
RAX: 0000000000080000 RBX: ffffc9000a6ffd98 RCX: ffffc90010e28000
RDX: 0000000000080000 RSI: ffffffff894c6e61 RDI: ffffc9000a6ffda0
RBP: ffffc9000a6ffaa8 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: ffffc9000a6ffbb0 R14: ffffc9000a6ffb90 R15: ffffc9000a6ffaa8
 copy_msghdr_from_user+0xc1/0x160 net/socket.c:2499
 recvmsg_copy_msghdr net/socket.c:2752 [inline]
 ___sys_recvmsg+0xdb/0x1a0 net/socket.c:2824
 do_recvmmsg+0x2fe/0x750 net/socket.c:2923
 __sys_recvmmsg net/socket.c:2997 [inline]
 __do_sys_recvmmsg net/socket.c:3020 [inline]
 __se_sys_recvmmsg net/socket.c:3013 [inline]
 __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3013
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb69258e929
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:00007fb69332c038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007fb6927b6080 RCX: 00007fb69258e929
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003
RBP: 00007fb692610b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fb6927b6080 R15: 00007ffeeea6beb8
 </TASK>

Allocated by task 19512:
 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+0x118/0x280 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:907 [inline]
 __se_sys_ioctl fs/ioctl.c:893 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 20874:
 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:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kfree+0x2b4/0x4d0 mm/slub.c:4842
 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+0xbc/0x410 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2230
 call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
 call_netdevice_notifiers net/core/dev.c:2282 [inline]
 dev_close_many+0x319/0x630 net/core/dev.c:1785
 netif_close net/core/dev.c:1798 [inline]
 netif_close+0x17f/0x230 net/core/dev.c:1792
 dev_close+0xaa/0x240 net/core/dev_api.c:220
 bpq_device_event+0x601/0x840 drivers/net/hamradio/bpqether.c:528
 notifier_call_chain+0xbc/0x410 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2230
 call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
 call_netdevice_notifiers net/core/dev.c:2282 [inline]
 __dev_notify_flags+0x1f7/0x2e0 net/core/dev.c:9499
 netif_change_flags+0x108/0x160 net/core/dev.c:9526
 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:823
 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:907 [inline]
 __se_sys_ioctl fs/ioctl.c:893 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888033fbf000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 42 bytes inside of
 freed 512-byte region [ffff888033fbf000, ffff888033fbf200)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888033fbdc00 pfn:0x33fbc
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000240 ffff88801b841c80 ffffea0001ea8610 ffffea00014ed810
raw: ffff888033fbdc00 000000000010000e 00000000f5000000 0000000000000000
head: 00fff00000000240 ffff88801b841c80 ffffea0001ea8610 ffffea00014ed810
head: ffff888033fbdc00 000000000010000e 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0000cfef01 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 12340, tgid 12340 (syz-executor), ts 801510986610, free_ts 797401311517
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x1321/0x3890 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:4959
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2451 [inline]
 allocate_slab mm/slub.c:2619 [inline]
 new_slab+0x23b/0x330 mm/slub.c:2673
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3859
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3949
 __slab_alloc_node mm/slub.c:4024 [inline]
 slab_alloc_node mm/slub.c:4185 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kmalloc_noprof+0x2f2/0x510 mm/slub.c:4340
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 fib6_info_alloc+0x40/0x160 net/ipv6/ip6_fib.c:155
 ip6_route_info_create+0x14c/0x870 net/ipv6/route.c:3811
 ip6_route_add.part.0+0x22/0x1d0 net/ipv6/route.c:3940
 ip6_route_add+0x45/0x60 net/ipv6/route.c:3937
 addrconf_prefix_route+0x2fd/0x510 net/ipv6/addrconf.c:2487
 inet6_addr_add+0x589/0x960 net/ipv6/addrconf.c:3052
 inet6_rtm_newaddr+0x1619/0x1c70 net/ipv6/addrconf.c:5063
 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6944
page last free pid 5838 tgid 5838 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 __free_frozen_pages+0x7fe/0x1180 mm/page_alloc.c:2706
 __folio_put+0x329/0x450 mm/swap.c:112
 __btree_node_data_free+0x351/0x4c0 fs/bcachefs/btree_cache.c:107
 bch2_fs_btree_cache_exit+0x759/0x10e0 fs/bcachefs/btree_cache.c:612
 __bch2_fs_free fs/bcachefs/super.c:620 [inline]
 bch2_fs_release+0x191/0xa10 fs/bcachefs/super.c:668
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1e7/0x5a0 lib/kobject.c:737
 deactivate_locked_super+0xc1/0x1a0 fs/super.c:474
 deactivate_super fs/super.c:507 [inline]
 deactivate_super+0xde/0x100 fs/super.c:503
 cleanup_mnt+0x225/0x450 fs/namespace.c:1417
 task_work_run+0x150/0x240 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:114
 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
 do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888033fbef00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888033fbef80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888033fbf000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff888033fbf080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888033fbf100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	45 31 e4             	xor    %r12d,%r12d
   3:	e8 01 ad 6f f8       	call   0xf86fad09
   8:	44 89 e0             	mov    %r12d,%eax
   b:	5b                   	pop    %rbx
   c:	5d                   	pop    %rbp
   d:	41 5c                	pop    %r12
   f:	41 5d                	pop    %r13
  11:	e9 be d2 c3 f7       	jmp    0xf7c3d2d4
  16:	e8 ee ac 6f f8       	call   0xf86fad09
  1b:	c7 43 08 00 00 00 00 	movl   $0x0,0x8(%rbx)
  22:	45 31 e4             	xor    %r12d,%r12d
  25:	e8 df ac 6f f8       	call   0xf86fad09
* 2a:	44 89 63 08          	mov    %r12d,0x8(%rbx) <-- trapping instruction
  2e:	4d 85 ed             	test   %r13,%r13
  31:	0f 85 c1 fe ff ff    	jne    0xfffffef8
  37:	e8 cd ac 6f f8       	call   0xf86fad09
  3c:	4c 8b 6d 00          	mov    0x0(%rbp),%r13