================================================================== BUG: KASAN: use-after-free in mutex_can_spin_on_owner kernel/locking/mutex.c:617 [inline] BUG: KASAN: use-after-free in mutex_optimistic_spin kernel/locking/mutex.c:661 [inline] BUG: KASAN: use-after-free in __mutex_lock_common kernel/locking/mutex.c:973 [inline] BUG: KASAN: use-after-free in __mutex_lock+0xcd7/0x1060 kernel/locking/mutex.c:1114 Read of size 4 at addr ffff8881d683bf38 by task syz-executor/17877 CPU: 0 PID: 17877 Comm: syz-executor Tainted: G W 5.4.290-syzkaller-00002-g41adfeb3d639 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1d8/0x241 lib/dump_stack.c:118 print_address_description+0x8c/0x600 mm/kasan/report.c:384 __kasan_report+0xf3/0x120 mm/kasan/report.c:516 kasan_report+0x30/0x60 mm/kasan/common.c:653 mutex_can_spin_on_owner kernel/locking/mutex.c:617 [inline] mutex_optimistic_spin kernel/locking/mutex.c:661 [inline] __mutex_lock_common kernel/locking/mutex.c:973 [inline] __mutex_lock+0xcd7/0x1060 kernel/locking/mutex.c:1114 mutex_lock_killable+0xd8/0x110 kernel/locking/mutex.c:1348 lo_open+0x18/0xc0 drivers/block/loop.c:1899 __blkdev_get+0x3c8/0x1160 fs/block_dev.c:1581 blkdev_get+0x2de/0x3a0 fs/block_dev.c:1714 do_dentry_open+0x964/0x1130 fs/open.c:806 do_last fs/namei.c:3565 [inline] path_openat+0x29bf/0x34b0 fs/namei.c:3683 do_filp_open+0x20b/0x450 fs/namei.c:3713 do_sys_open+0x39c/0x810 fs/open.c:1123 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 RIP: 0033:0x7ffacd27fa51 Code: 75 57 89 f0 25 00 00 41 00 3d 00 00 41 00 74 49 80 3d fa 1a 1f 00 00 74 6d 89 da 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 93 00 00 00 48 8b 54 24 28 64 48 2b 14 25 RSP: 002b:00007fff6a25f090 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007ffacd27fa51 RDX: 0000000000000002 RSI: 00007fff6a25f1a0 RDI: 00000000ffffff9c RBP: 00007fff6a25f1a0 R08: 000000000000000a R09: 00007fff6a25ee57 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffacd46a260 R14: 0000000000000003 R15: 00007fff6a25f1a0 Allocated by task 17844: save_stack mm/kasan/common.c:70 [inline] set_track mm/kasan/common.c:78 [inline] __kasan_kmalloc+0x171/0x210 mm/kasan/common.c:529 slab_post_alloc_hook mm/slab.h:584 [inline] slab_alloc_node mm/slub.c:2829 [inline] slab_alloc mm/slub.c:2837 [inline] kmem_cache_alloc+0xd9/0x250 mm/slub.c:2842 kmem_cache_alloc_node include/linux/slab.h:427 [inline] alloc_task_struct_node kernel/fork.c:171 [inline] dup_task_struct+0x4f/0x600 kernel/fork.c:882 copy_process+0x56d/0x3230 kernel/fork.c:1889 _do_fork+0x197/0x900 kernel/fork.c:2399 __do_sys_clone3 kernel/fork.c:2688 [inline] __se_sys_clone3 kernel/fork.c:2675 [inline] __x64_sys_clone3+0x2da/0x300 kernel/fork.c:2675 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Freed by task 10: save_stack mm/kasan/common.c:70 [inline] set_track mm/kasan/common.c:78 [inline] kasan_set_free_info mm/kasan/common.c:345 [inline] __kasan_slab_free+0x1b5/0x270 mm/kasan/common.c:487 slab_free_hook mm/slub.c:1455 [inline] slab_free_freelist_hook mm/slub.c:1494 [inline] slab_free mm/slub.c:3080 [inline] kmem_cache_free+0x10b/0x2c0 mm/slub.c:3096 __rcu_reclaim kernel/rcu/rcu.h:222 [inline] rcu_do_batch+0x492/0xa00 kernel/rcu/tree.c:2167 rcu_core+0x4c8/0xcb0 kernel/rcu/tree.c:2387 __do_softirq+0x23b/0x6b7 kernel/softirq.c:292 The buggy address belongs to the object at ffff8881d683bf00 which belongs to the cache task_struct of size 3904 The buggy address is located 56 bytes inside of 3904-byte region [ffff8881d683bf00, ffff8881d683ce40) The buggy address belongs to the page: page:ffffea00075a0e00 refcount:1 mapcount:0 mapping:ffff8881f5cf0280 index:0xffff8881d6839f80 compound_mapcount: 0 flags: 0x8000000000010200(slab|head) raw: 8000000000010200 ffffea000717b808 ffffea0006f9a608 ffff8881f5cf0280 raw: ffff8881d6839f80 0000000000080007 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL) set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook mm/page_alloc.c:2165 [inline] prep_new_page+0x18f/0x370 mm/page_alloc.c:2171 get_page_from_freelist+0x2d13/0x2d90 mm/page_alloc.c:3794 __alloc_pages_nodemask+0x393/0x840 mm/page_alloc.c:4893 alloc_slab_page+0x39/0x3c0 mm/slub.c:343 allocate_slab mm/slub.c:1683 [inline] new_slab+0x97/0x440 mm/slub.c:1749 new_slab_objects mm/slub.c:2505 [inline] ___slab_alloc+0x2fe/0x490 mm/slub.c:2667 __slab_alloc+0x62/0xa0 mm/slub.c:2707 slab_alloc_node mm/slub.c:2792 [inline] slab_alloc mm/slub.c:2837 [inline] kmem_cache_alloc+0x109/0x250 mm/slub.c:2842 kmem_cache_alloc_node include/linux/slab.h:427 [inline] alloc_task_struct_node kernel/fork.c:171 [inline] dup_task_struct+0x4f/0x600 kernel/fork.c:882 copy_process+0x56d/0x3230 kernel/fork.c:1889 _do_fork+0x197/0x900 kernel/fork.c:2399 kernel_thread+0x16a/0x1d0 kernel/fork.c:2489 create_kthread kernel/kthread.c:311 [inline] kthreadd+0x3b1/0x4f0 kernel/kthread.c:654 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1176 [inline] free_pcp_prepare mm/page_alloc.c:1233 [inline] free_unref_page_prepare+0x297/0x380 mm/page_alloc.c:3085 free_unref_page_list+0x10a/0x590 mm/page_alloc.c:3154 release_pages+0xad8/0xb20 mm/swap.c:842 __pagevec_release+0xc3/0x150 mm/swap.c:862 pagevec_release include/linux/pagevec.h:88 [inline] truncate_inode_pages_range+0xa6b/0x1a20 mm/truncate.c:367 f2fs_evict_inode+0x113/0x11e0 fs/f2fs/inode.c:751 evict+0x4ea/0x960 fs/inode.c:610 dispose_list fs/inode.c:645 [inline] evict_inodes+0x63c/0x6c0 fs/inode.c:699 generic_shutdown_super+0x94/0x300 fs/super.c:454 kill_block_super+0x7a/0xe0 fs/super.c:1455 kill_f2fs_super+0x2f9/0x3c0 fs/f2fs/super.c:4348 deactivate_locked_super+0xa8/0x110 fs/super.c:335 deactivate_super+0x1e2/0x2a0 fs/super.c:366 cleanup_mnt+0x44e/0x500 fs/namespace.c:1102 task_work_run+0x140/0x170 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x190/0x1a0 arch/x86/entry/common.c:163 Memory state around the buggy address: ffff8881d683be00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881d683be80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8881d683bf00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881d683bf80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881d683c000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb 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