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BUG: KASAN: slab-use-after-free in jfs_lazycommit+0x6d7/0xa10
Read of size 4 at addr ffff88810ba7b894 by task jfsCommit/132

CPU: 0 UID: 0 PID: 132 Comm: jfsCommit Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 print_address_description+0x55/0x1e0
 print_report+0x58/0x70
 kasan_report+0x117/0x150
 jfs_lazycommit+0x6d7/0xa10
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Allocated by task 26425:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_cache_noprof+0x3a6/0x690
 jfs_fill_super+0xc2/0xd80
 get_tree_bdev_flags+0x431/0x4f0
 vfs_get_tree+0x92/0x2a0
 do_new_mount+0x341/0xd30
 __se_sys_mount+0x31d/0x420
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 22535:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5c/0x80
 kfree+0x1c5/0x6c0
 generic_shutdown_super+0x13d/0x2d0
 kill_block_super+0x44/0x90
 deactivate_locked_super+0xbc/0x130
 cleanup_mnt+0x437/0x4d0
 task_work_run+0x1d9/0x270
 exit_to_user_mode_loop+0xf3/0x4d0
 do_syscall_64+0x33e/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88810ba7b800
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 148 bytes inside of
 freed 256-byte region [ffff88810ba7b800, ffff88810ba7b900)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10ba7a
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x100000000000040(head|node=0|zone=2)
page_type: f5(slab)
raw: 0100000000000040 ffff888100041b40 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 0100000000000040 ffff888100041b40 dead000000000100 dead000000000122
head: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 0100000000000001 ffffffffffffff81 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 9798, tgid 9794 (syz.4.1848), ts 182005362952, free_ts 181396126749
 post_alloc_hook+0x1f9/0x250
 get_page_from_freelist+0x27d6/0x2850
 __alloc_frozen_pages_noprof+0x18d/0x380
 allocate_slab+0x74/0x5e0
 refill_objects+0x33c/0x3d0
 __pcs_replace_empty_main+0x373/0x720
 __kmalloc_noprof+0x530/0x7b0
 iter_file_splice_write+0x1dd/0x10f0
 direct_splice_actor+0x104/0x160
 splice_direct_to_actor+0x545/0xc80
 do_splice_direct+0x19b/0x2a0
 do_sendfile+0x547/0x7e0
 __se_sys_sendfile64+0x144/0x1a0
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 9307 tgid 9307 stack trace:
 __free_frozen_pages+0x1075/0x11b0
 __slab_free+0x252/0x2a0
 qlist_free_all+0x99/0x100
 kasan_quarantine_reduce+0x148/0x160
 __kasan_slab_alloc+0x22/0x80
 kmem_cache_alloc_noprof+0x33b/0x680
 do_getname+0x2e/0x250
 do_sys_openat2+0xca/0x200
 __x64_sys_openat+0x138/0x170
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88810ba7b780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88810ba7b800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88810ba7b880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff88810ba7b900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88810ba7b980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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