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BUG: KASAN: slab-use-after-free in __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166
Read of size 1 at addr ffff88803ec08868 by task syz.2.22/5895

CPU: 1 UID: 0 PID: 5895 Comm: syz.2.22 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 __kasan_check_byte+0x2a/0x40 mm/kasan/common.c:574
 kasan_check_byte include/linux/kasan.h:402 [inline]
 lock_acquire+0x84/0x350 kernel/locking/lockdep.c:5844
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
 _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166
 rt_mutex_slowunlock+0xbf/0x8b0 kernel/locking/rtmutex.c:1430
 spin_unlock include/linux/spinlock_rt.h:109 [inline]
 class_spinlock_destructor include/linux/spinlock.h:587 [inline]
 dma_buf_fd+0x178/0x330 drivers/dma-buf/dma-buf.c:796
 dma_heap_buffer_alloc drivers/dma-buf/dma-heap.c:76 [inline]
 dma_heap_ioctl_allocate drivers/dma-buf/dma-heap.c:116 [inline]
 dma_heap_ioctl+0x50b/0x620 drivers/dma-buf/dma-heap.c:176
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xff/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fce45f8ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fce441bd028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fce46206090 RCX: 00007fce45f8ce59
RDX: 0000200000000000 RSI: 000000004008af00 RDI: 0000000000000003
RBP: 00007fce46022d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fce46206128 R14: 00007fce46206090 R15: 00007ffd9c92db18
 </TASK>

Allocated by task 5895:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5308 [inline]
 __kmalloc_noprof+0x3e7/0x7b0 mm/slub.c:5320
 kmalloc_noprof include/linux/slab.h:954 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 dma_buf_export+0x3ba/0xad0 drivers/dma-buf/dma-buf.c:739
 system_heap_allocate+0xf11/0x1430 drivers/dma-buf/heaps/system_heap.c:473
 dma_heap_buffer_alloc drivers/dma-buf/dma-heap.c:72 [inline]
 dma_heap_ioctl_allocate drivers/dma-buf/dma-heap.c:116 [inline]
 dma_heap_ioctl+0x4ce/0x620 drivers/dma-buf/dma-heap.c:176
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xff/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5901:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2700 [inline]
 slab_free mm/slub.c:6291 [inline]
 kfree+0x1c5/0x6c0 mm/slub.c:6606
 __dentry_kill+0x211/0x690 fs/dcache.c:723
 finish_dput+0xc9/0x480 fs/dcache.c:927
 __fput+0x6a3/0xa70 fs/file_table.c:518
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xf3/0x4d0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88803ec08800
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 104 bytes inside of
 freed 1024-byte region [ffff88803ec08800, ffff88803ec08c00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3ec08
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88813fe16dc0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88813fe16dc0 dead000000000100 dead000000000122
head: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 0080000000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5895, tgid 5879 (syz.2.22), ts 109027437906, free_ts 108982701090
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1861
 prep_new_page mm/page_alloc.c:1869 [inline]
 get_page_from_freelist+0x27d6/0x2850 mm/page_alloc.c:3949
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5292
 alloc_slab_page mm/slub.c:3289 [inline]
 allocate_slab+0x74/0x5e0 mm/slub.c:3404
 new_slab mm/slub.c:3447 [inline]
 refill_objects+0x33c/0x3d0 mm/slub.c:7319
 refill_sheaf mm/slub.c:2827 [inline]
 __pcs_replace_empty_main+0x373/0x720 mm/slub.c:4664
 alloc_from_pcs mm/slub.c:4762 [inline]
 slab_alloc_node mm/slub.c:4896 [inline]
 __do_kmalloc_node mm/slub.c:5307 [inline]
 __kmalloc_noprof+0x530/0x7b0 mm/slub.c:5320
 kmalloc_noprof include/linux/slab.h:954 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 dma_buf_export+0x3ba/0xad0 drivers/dma-buf/dma-buf.c:739
 system_heap_allocate+0xf11/0x1430 drivers/dma-buf/heaps/system_heap.c:473
 dma_heap_buffer_alloc drivers/dma-buf/dma-heap.c:72 [inline]
 dma_heap_ioctl_allocate drivers/dma-buf/dma-heap.c:116 [inline]
 dma_heap_ioctl+0x4ce/0x620 drivers/dma-buf/dma-heap.c:176
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xff/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 12 tgid 12 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1405 [inline]
 __free_frozen_pages+0x1075/0x11b0 mm/page_alloc.c:2946
 __slab_free+0x252/0x2a0 mm/slub.c:5653
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4582 [inline]
 slab_alloc_node mm/slub.c:4911 [inline]
 kmem_cache_alloc_node_noprof+0x22a/0x6e0 mm/slub.c:4963
 __alloc_skb+0x1d0/0x7d0 net/core/skbuff.c:702
 alloc_skb include/linux/skbuff.h:1381 [inline]
 mld_newpack+0x14c/0xc90 net/ipv6/mcast.c:1762
 add_grhead+0x5a/0x2a0 net/ipv6/mcast.c:1873
 add_grec+0x1452/0x1740 net/ipv6/mcast.c:2012
 mld_send_initial_cr+0x288/0x550 net/ipv6/mcast.c:2255
 ipv6_mc_dad_complete+0x88/0x540 net/ipv6/mcast.c:2266
 addrconf_dad_completed+0x622/0xe60 net/ipv6/addrconf.c:4352
 addrconf_dad_work+0xdc4/0x1680 include/linux/rwlock_rt.h:-1
 process_one_work+0x98b/0x1630 kernel/workqueue.c:3306
 process_scheduled_works kernel/workqueue.c:3389 [inline]
 worker_thread+0xb49/0x1140 kernel/workqueue.c:3470

Memory state around the buggy address:
 ffff88803ec08700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88803ec08780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88803ec08800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                          ^
 ffff88803ec08880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88803ec08900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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