syzbot

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BUG: KASAN: slab-use-after-free in sk_psock_verdict_data_ready+0x6c/0x390 net/core/skmsg.c:1233
Read of size 8 at addr ffff88807b07da20 by task syz.4.92/6265

CPU: 0 UID: 0 PID: 6265 Comm: syz.4.92 Not tainted 6.15.0-rc4-syzkaller-00746-g836b313a14a3 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xb4/0x290 mm/kasan/report.c:521
 kasan_report+0x118/0x150 mm/kasan/report.c:634
 sk_psock_verdict_data_ready+0x6c/0x390 net/core/skmsg.c:1233
 unix_stream_sendmsg+0x64c/0xb60 net/unix/af_unix.c:2321
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:727
 ____sys_sendmsg+0x505/0x830 net/socket.c:2566
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620
 __sys_sendmsg net/socket.c:2652 [inline]
 __do_sys_sendmsg net/socket.c:2657 [inline]
 __se_sys_sendmsg net/socket.c:2655 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2655
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4b9a38e969
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:00007f4b9b1e6038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f4b9a5b6080 RCX: 00007f4b9a38e969
RDX: 0000000000000003 RSI: 0000200000000980 RDI: 000000000000000c
RBP: 00007f4b9a410ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f4b9a5b6080 R15: 00007ffc0db5b908
 </TASK>

Allocated by task 6265:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4161 [inline]
 slab_alloc_node mm/slub.c:4210 [inline]
 kmem_cache_alloc_lru_noprof+0x1c6/0x3d0 mm/slub.c:4229
 sock_alloc_inode+0x28/0xc0 net/socket.c:309
 alloc_inode+0x67/0x1b0 fs/inode.c:346
 new_inode_pseudo include/linux/fs.h:3309 [inline]
 sock_alloc net/socket.c:622 [inline]
 __sock_create+0x12d/0x9f0 net/socket.c:1505
 sock_create net/socket.c:1599 [inline]
 __sys_socketpair+0x23a/0x560 net/socket.c:1750
 __do_sys_socketpair net/socket.c:1799 [inline]
 __se_sys_socketpair net/socket.c:1796 [inline]
 __x64_sys_socketpair+0x9b/0xb0 net/socket.c:1796
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 15:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2398 [inline]
 slab_free mm/slub.c:4656 [inline]
 kmem_cache_free+0x192/0x3f0 mm/slub.c:4758
 rcu_do_batch kernel/rcu/tree.c:2568 [inline]
 rcu_core+0xca5/0x1710 kernel/rcu/tree.c:2824
 handle_softirqs+0x283/0x870 kernel/softirq.c:579
 run_ksoftirqd+0x9b/0x100 kernel/softirq.c:968
 smpboot_thread_fn+0x53f/0xa60 kernel/smpboot.c:164
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47
 kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:548
 __call_rcu_common kernel/rcu/tree.c:3082 [inline]
 call_rcu+0x142/0x990 kernel/rcu/tree.c:3202
 destroy_inode fs/inode.c:401 [inline]
 evict+0x847/0x9c0 fs/inode.c:834
 __dentry_kill+0x209/0x660 fs/dcache.c:660
 dput+0x19f/0x2b0 fs/dcache.c:902
 __fput+0x68e/0xa70 fs/file_table.c:473
 task_work_run+0x1d1/0x260 kernel/task_work.c:227
 resume_user_mode_work+0x5e/0x80 include/linux/resume_user_mode.h:50
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x9a/0x120 kernel/entry/common.c:218
 do_syscall_64+0x103/0x210 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88807b07da00
 which belongs to the cache sock_inode_cache of size 1408
The buggy address is located 32 bytes inside of
 freed 1408-byte region [ffff88807b07da00, ffff88807b07df80)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807b07aa00 pfn:0x7b078
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888030360c01
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801e2e8dc0 ffffea0001ec6c00 0000000000000002
raw: ffff88807b07aa00 0000000000150013 00000000f5000000 ffff888030360c01
head: 00fff00000000040 ffff88801e2e8dc0 ffffea0001ec6c00 0000000000000002
head: ffff88807b07aa00 0000000000150013 00000000f5000000 ffff888030360c01
head: 00fff00000000003 ffffea0001ec1e01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Reclaimable, gfp_mask 0xd20d0(__GFP_RECLAIMABLE|__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5495, tgid 5495 (dhcpcd), ts 68499125647, free_ts 29042625498
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1d8/0x230 mm/page_alloc.c:1714
 prep_new_page mm/page_alloc.c:1722 [inline]
 get_page_from_freelist+0x21e0/0x22c0 mm/page_alloc.c:3684
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4966
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2468 [inline]
 allocate_slab+0x8a/0x3b0 mm/slub.c:2632
 new_slab mm/slub.c:2686 [inline]
 ___slab_alloc+0xbfc/0x1480 mm/slub.c:3872
 __slab_alloc mm/slub.c:3962 [inline]
 __slab_alloc_node mm/slub.c:4037 [inline]
 slab_alloc_node mm/slub.c:4198 [inline]
 kmem_cache_alloc_lru_noprof+0x288/0x3d0 mm/slub.c:4229
 sock_alloc_inode+0x28/0xc0 net/socket.c:309
 alloc_inode+0x67/0x1b0 fs/inode.c:346
 new_inode_pseudo include/linux/fs.h:3309 [inline]
 sock_alloc net/socket.c:622 [inline]
 __sock_create+0x12d/0x9f0 net/socket.c:1505
 sock_create net/socket.c:1599 [inline]
 __sys_socket_create net/socket.c:1636 [inline]
 __sys_socket+0xd7/0x1b0 net/socket.c:1683
 __do_sys_socket net/socket.c:1697 [inline]
 __se_sys_socket net/socket.c:1695 [inline]
 __x64_sys_socket+0x7a/0x90 net/socket.c:1695
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
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:1258 [inline]
 __free_frozen_pages+0xb14/0xce0 mm/page_alloc.c:2721
 __free_pages mm/page_alloc.c:5076 [inline]
 free_contig_range+0x159/0x440 mm/page_alloc.c:6932
 destroy_args+0x86/0x460 mm/debug_vm_pgtable.c:1017
 debug_vm_pgtable+0x3cf/0x410 mm/debug_vm_pgtable.c:1397
 do_one_initcall+0x233/0x820 init/main.c:1257
 do_initcall_level+0x137/0x1f0 init/main.c:1319
 do_initcalls+0x69/0xd0 init/main.c:1335
 kernel_init_freeable+0x3d9/0x570 init/main.c:1567
 kernel_init+0x1d/0x1d0 init/main.c:1457
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff88807b07d900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807b07d980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88807b07da00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff88807b07da80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807b07db00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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