KASAN: slab-use-after-free Read in lock_timer

Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported
KASAN: slab-use-after-free Read in __timer_delete_sync mptcp	syz	error		1	15d	13d
Title	Replies (including bot)	Last reply
[syzbot] [mptcp?] KASAN: slab-use-after-free Read in lock_timer_base	1 (2)	2024/09/09 15:31
Kernel	Title	Count	Last	Reported	Patched	Status
linux-4.14	general protection fault in lock_timer_base (3)	2	1293d	1310d	0/1	auto-closed as invalid on 2021/06/30 20:28
linux-4.14	general protection fault in lock_timer_base (4)	2	864d	871d	0/1	auto-obsoleted due to no activity on 2022/09/03 04:12
upstream	UBSAN: array-index-out-of-bounds in lock_timer_base bcachefs kvm	4	91d	105d	26/28	fixed on 2024/07/09 19:14
TCP: request_sock_subflow_v4: Possible SYN flooding on port [::]:20002. Sending cookies.
==================================================================
BUG: KASAN: slab-use-after-free in lock_timer_base+0x1a7/0x240 kernel/time/timer.c:1052
Read of size 4 at addr ffff888029b38e50 by task kworker/0:2/940

CPU: 0 UID: 0 PID: 940 Comm: kworker/0:2 Not tainted 6.11.0-rc5-syzkaller-00219-g1934261d8974 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Workqueue: events mptcp_worker
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 lock_timer_base+0x1a7/0x240 kernel/time/timer.c:1052
 __try_to_del_timer_sync+0xb5/0x340 kernel/time/timer.c:1506
 __timer_delete_sync+0x245/0x310 kernel/time/timer.c:1665
 del_timer_sync include/linux/timer.h:185 [inline]
 sk_stop_timer_sync+0x1c/0x90 net/core/sock.c:3454
 mptcp_pm_del_add_timer+0x18d/0x250 net/mptcp/pm_netlink.c:345
 mptcp_incoming_options+0x158d/0x2570 net/mptcp/options.c:1166
 tcp_data_queue+0xf5/0x76c0 net/ipv4/tcp_input.c:5206
 tcp_rcv_established+0xfba/0x2020 net/ipv4/tcp_input.c:6230
 tcp_v4_do_rcv+0x96d/0xc70 net/ipv4/tcp_ipv4.c:1911
 tcp_v4_rcv+0x2dc0/0x37f0 net/ipv4/tcp_ipv4.c:2346
 ip_protocol_deliver_rcu+0x22e/0x440 net/ipv4/ip_input.c:205
 ip_local_deliver_finish+0x341/0x5f0 net/ipv4/ip_input.c:233
 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314
 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314
 __netif_receive_skb_one_core net/core/dev.c:5661 [inline]
 __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5775
 process_backlog+0x662/0x15b0 net/core/dev.c:6108
 __napi_poll+0xcb/0x490 net/core/dev.c:6772
 napi_poll net/core/dev.c:6841 [inline]
 net_rx_action+0x89b/0x1240 net/core/dev.c:6963
 handle_softirqs+0x2c4/0x970 kernel/softirq.c:554
 do_softirq+0x11b/0x1e0 kernel/softirq.c:455
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:382
 mptcp_pm_send_ack net/mptcp/pm_netlink.c:496 [inline]
 mptcp_pm_nl_addr_send_ack+0x3ec/0x4e0 net/mptcp/pm_netlink.c:785
 mptcp_pm_nl_work+0x18e8/0x1fc0 net/mptcp/pm_netlink.c:924
 mptcp_worker+0x12f/0x1440 net/mptcp/protocol.c:2759
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
 worker_thread+0x86d/0xd10 kernel/workqueue.c:3389
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Allocated by task 940:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
 __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __kmalloc_cache_noprof+0x19c/0x2c0 mm/slub.c:4189
 kmalloc_noprof include/linux/slab.h:681 [inline]
 mptcp_pm_alloc_anno_list+0x14e/0x390 net/mptcp/pm_netlink.c:370
 mptcp_pm_create_subflow_or_signal_addr+0x1920/0x22c0 net/mptcp/pm_netlink.c:586
 mptcp_pm_nl_fully_established net/mptcp/pm_netlink.c:640 [inline]
 mptcp_pm_nl_work+0x19ae/0x1fc0 net/mptcp/pm_netlink.c:932
 mptcp_worker+0x12f/0x1440 net/mptcp/protocol.c:2759
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
 worker_thread+0x86d/0xd10 kernel/workqueue.c:3389
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Freed by task 12966:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
 poison_slab_object+0xe0/0x150 mm/kasan/common.c:240
 __kasan_slab_free+0x37/0x60 mm/kasan/common.c:256
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2252 [inline]
 slab_free mm/slub.c:4473 [inline]
 kfree+0x149/0x360 mm/slub.c:4594
 remove_anno_list_by_saddr+0x156/0x190 net/mptcp/pm_netlink.c:1466
 mptcp_pm_remove_addrs_and_subflows net/mptcp/pm_netlink.c:1687 [inline]
 mptcp_nl_remove_addrs_list net/mptcp/pm_netlink.c:1718 [inline]
 mptcp_pm_nl_flush_addrs_doit+0x664/0xd60 net/mptcp/pm_netlink.c:1759
 genl_family_rcv_msg_doit net/netlink/genetlink.c:1115 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
 genl_rcv_msg+0xb14/0xec0 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2550
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline]
 netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1357
 netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:745
 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2597
 ___sys_sendmsg net/socket.c:2651 [inline]
 __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2680
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888029b38e00
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 80 bytes inside of
 freed 192-byte region [ffff888029b38e00, ffff888029b38ec0)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x29b38
ksm flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xfdffffff(slab)
raw: 00fff00000000000 ffff88801ac413c0 ffffea0000bd3380 dead000000000003
raw: 0000000000000000 0000000080100010 00000001fdffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x352800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL|__GFP_THISNODE), pid 5573, tgid 5573 (cmp), ts 78576722831, free_ts 78537901249
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1493
 prep_new_page mm/page_alloc.c:1501 [inline]
 get_page_from_freelist+0x2e4c/0x2f10 mm/page_alloc.c:3439
 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4695
 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
 alloc_slab_page+0x5f/0x120 mm/slub.c:2321
 allocate_slab+0x5a/0x2f0 mm/slub.c:2484
 new_slab mm/slub.c:2537 [inline]
 ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3723
 __slab_alloc+0x58/0xa0 mm/slub.c:3813
 __slab_alloc_node mm/slub.c:3866 [inline]
 slab_alloc_node mm/slub.c:4025 [inline]
 __do_kmalloc_node mm/slub.c:4157 [inline]
 __kmalloc_node_noprof+0x286/0x440 mm/slub.c:4164
 kmalloc_array_node_noprof include/linux/slab.h:788 [inline]
 alloc_slab_obj_exts mm/slub.c:1976 [inline]
 account_slab mm/slub.c:2447 [inline]
 allocate_slab+0xb6/0x2f0 mm/slub.c:2502
 new_slab mm/slub.c:2537 [inline]
 ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3723
 __slab_alloc+0x58/0xa0 mm/slub.c:3813
 __slab_alloc_node mm/slub.c:3866 [inline]
 slab_alloc_node mm/slub.c:4025 [inline]
 kmem_cache_alloc_noprof+0x1c1/0x2a0 mm/slub.c:4044
 vma_lock_alloc kernel/fork.c:445 [inline]
 vm_area_dup+0x61/0x290 kernel/fork.c:498
 __split_vma+0x1a9/0xc30 mm/mmap.c:2465
 do_vmi_align_munmap+0x433/0x18c0 mm/mmap.c:2676
 do_vmi_munmap+0x261/0x2f0 mm/mmap.c:2830
page last free pid 5572 tgid 5572 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1094 [inline]
 free_unref_folios+0x103a/0x1b00 mm/page_alloc.c:2660
 folios_put_refs+0x76e/0x860 mm/swap.c:1039
 free_pages_and_swap_cache+0x5c8/0x690 mm/swap_state.c:335
 __tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline]
 tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:366 [inline]
 tlb_flush_mmu+0x3a3/0x680 mm/mmu_gather.c:373
 tlb_finish_mmu+0xd4/0x200 mm/mmu_gather.c:465
 exit_mmap+0x44f/0xc80 mm/mmap.c:3425
 __mmput+0x115/0x390 kernel/fork.c:1345
 exit_mm+0x220/0x310 kernel/exit.c:571
 do_exit+0x9b2/0x27f0 kernel/exit.c:869
 do_group_exit+0x207/0x2c0 kernel/exit.c:1031
 __do_sys_exit_group kernel/exit.c:1042 [inline]
 __se_sys_exit_group kernel/exit.c:1040 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1040
 x64_sys_call+0x2634/0x2640 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888029b38d00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888029b38d80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff888029b38e00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff888029b38e80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff888029b38f00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================