syzbot


KASAN: slab-use-after-free Write in rose_t0timer_expiry

Status: upstream: reported on 2025/09/25 18:49
Subsystems: hams
[Documentation on labels]
Reported-by: syzbot+350060a9356421ae83dc@syzkaller.appspotmail.com
First crash: 64d, last: 30d
Discussions (2)
Title Replies (including bot) Last reply
[syzbot] Monthly hams report (Oct 2025) 0 (1) 2025/10/24 18:48
[syzbot] [hams?] KASAN: slab-use-after-free Write in rose_t0timer_expiry 0 (1) 2025/09/25 18:49

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in rose_t0timer_expiry+0x114/0x150 net/rose/rose_link.c:85
Write of size 1 at addr ffff888057fe3c35 by task syz.2.2523/14463

CPU: 1 UID: 0 PID: 14463 Comm: syz.2.2523 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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:378 [inline]
 print_report+0xcd/0x630 mm/kasan/report.c:482
 kasan_report+0xe0/0x110 mm/kasan/report.c:595
 rose_t0timer_expiry+0x114/0x150 net/rose/rose_link.c:85
 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:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x109/0x170 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1052
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:finish_task_switch.isra.0+0x22a/0xc10 kernel/sched/core.c:5193
Code: fb 09 00 00 44 8b 05 39 ed f7 0e 45 85 c0 0f 85 be 01 00 00 4c 89 e7 e8 a4 f6 ff ff e8 cf d3 3a 00 fb 65 48 8b 1d de 27 17 12 <48> 8d bb 58 16 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1
RSP: 0018:ffffc90003b176d0 EFLAGS: 00000202
RAX: 0000000000016345 RBX: ffff8880301a0000 RCX: ffffffff81c50aff
RDX: 0000000000000000 RSI: ffffffff8da2a268 RDI: ffffffff8bf06cc0
RBP: ffffc90003b17718 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff9081f4d7 R11: 0000000000000001 R12: ffff8880b853a380
R13: ffff88801d682480 R14: ffff8880b843a380 R15: ffff8880b853b1b0
 context_switch kernel/sched/core.c:5328 [inline]
 __schedule+0x1198/0x5de0 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7026
 schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:100 [inline]
 __wait_for_common+0x2fc/0x4e0 kernel/sched/completion.c:121
 rdmsr_safe_on_cpu+0x1dc/0x210 arch/x86/lib/msr-smp.c:181
 msr_read+0x19d/0x250 arch/x86/kernel/msr.c:66
 vfs_read+0x1e4/0xcf0 fs/read_write.c:570
 ksys_read+0x12a/0x250 fs/read_write.c:715
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fadd618efc9
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:00007fadd43d5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fadd63e6090 RCX: 00007fadd618efc9
RDX: 0000000000018ff8 RSI: 000020000001b700 RDI: 0000000000000004
RBP: 00007fadd6211f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fadd63e6128 R14: 00007fadd63e6090 R15: 00007ffe8c1ea638
 </TASK>

Allocated by task 12521:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:417
 kmalloc_noprof include/linux/slab.h:957 [inline]
 rose_add_node net/rose/rose_route.c:85 [inline]
 rose_rt_ioctl+0x880/0x2580 net/rose/rose_route.c:748
 rose_ioctl+0x64d/0x7c0 net/rose/af_rose.c:1381
 sock_do_ioctl+0x118/0x280 net/socket.c:1254
 sock_ioctl+0x227/0x6b0 net/socket.c:1375
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 0:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 __kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:587
 kasan_save_free_info mm/kasan/kasan.h:406 [inline]
 poison_slab_object mm/kasan/common.c:252 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2530 [inline]
 slab_free mm/slub.c:6619 [inline]
 kfree+0x2b8/0x6d0 mm/slub.c:6826
 rose_neigh_put include/net/rose.h:166 [inline]
 rose_timer_expiry+0x53f/0x630 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:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x109/0x170 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1052
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697

The buggy address belongs to the object at ffff888057fe3c00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 53 bytes inside of
 freed 512-byte region [ffff888057fe3c00, ffff888057fe3e00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x57fe0
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 ffff88813ffa6c80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813ffa6c80 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea00015ff801 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 3580, tgid 3580 (kworker/u8:8), ts 62929132847, free_ts 14103490860
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1850
 prep_new_page mm/page_alloc.c:1858 [inline]
 get_page_from_freelist+0x10a3/0x3a30 mm/page_alloc.c:3884
 __alloc_frozen_pages_noprof+0x25f/0x2470 mm/page_alloc.c:5183
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:3046 [inline]
 allocate_slab mm/slub.c:3219 [inline]
 new_slab+0x24a/0x360 mm/slub.c:3273
 ___slab_alloc+0xdc4/0x1ae0 mm/slub.c:4643
 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4762
 __slab_alloc_node mm/slub.c:4838 [inline]
 slab_alloc_node mm/slub.c:5260 [inline]
 __kmalloc_cache_noprof+0x477/0x780 mm/slub.c:5750
 kmalloc_noprof include/linux/slab.h:957 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 mca_alloc net/ipv6/mcast.c:871 [inline]
 __ipv6_dev_mc_inc+0x2f1/0xbc0 net/ipv6/mcast.c:961
 addrconf_join_solict net/ipv6/addrconf.c:2246 [inline]
 addrconf_dad_begin net/ipv6/addrconf.c:4099 [inline]
 addrconf_dad_work+0x28c/0x14e0 net/ipv6/addrconf.c:4227
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
 process_scheduled_works kernel/workqueue.c:3346 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page last free pid 1 tgid 1 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1394 [inline]
 __free_frozen_pages+0x7df/0x1160 mm/page_alloc.c:2906
 __free_pages mm/page_alloc.c:5302 [inline]
 free_contig_range+0x183/0x4b0 mm/page_alloc.c:7146
 destroy_args+0xb69/0x12e0 mm/debug_vm_pgtable.c:958
 debug_vm_pgtable+0x1a32/0x3640 mm/debug_vm_pgtable.c:1345
 do_one_initcall+0x123/0x6e0 init/main.c:1283
 do_initcall_level init/main.c:1345 [inline]
 do_initcalls init/main.c:1361 [inline]
 do_basic_setup init/main.c:1380 [inline]
 kernel_init_freeable+0x5c8/0x920 init/main.c:1593
 kernel_init+0x1c/0x2b0 init/main.c:1483
 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff888057fe3b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888057fe3b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888057fe3c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff888057fe3c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888057fe3d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	fb                   	sti
   1:	09 00                	or     %eax,(%rax)
   3:	00 44 8b 05          	add    %al,0x5(%rbx,%rcx,4)
   7:	39 ed                	cmp    %ebp,%ebp
   9:	f7 0e 45 85 c0 0f    	testl  $0xfc08545,(%rsi)
   f:	85 be 01 00 00 4c    	test   %edi,0x4c000001(%rsi)
  15:	89 e7                	mov    %esp,%edi
  17:	e8 a4 f6 ff ff       	call   0xfffff6c0
  1c:	e8 cf d3 3a 00       	call   0x3ad3f0
  21:	fb                   	sti
  22:	65 48 8b 1d de 27 17 	mov    %gs:0x121727de(%rip),%rbx        # 0x12172808
  29:	12
* 2a:	48 8d bb 58 16 00 00 	lea    0x1658(%rbx),%rdi <-- trapping instruction
  31:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  38:	fc ff df
  3b:	48 89 fa             	mov    %rdi,%rdx
  3e:	48                   	rex.W
  3f:	c1                   	.byte 0xc1

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/24 07:02 upstream 6fab32bb6508 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-use-after-free Write in rose_t0timer_expiry
2025/09/20 03:37 upstream e8442d5b7bc6 67c37560 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-use-after-free Write in rose_t0timer_expiry
* Struck through repros no longer work on HEAD.