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BUG: KASAN: slab-use-after-free in jfs_lazycommit+0x749/0xaa0
Read of size 4 at addr ffff888115c9fe94 by task jfsCommit/117

CPU: 1 UID: 0 PID: 117 Comm: jfsCommit Not tainted syzkaller #0 PREEMPT(full) 
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_report+0xba/0x230
 kasan_report+0x117/0x150
 jfs_lazycommit+0x749/0xaa0
 kthread+0x726/0x8b0
 ret_from_fork+0x51b/0xa40
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Allocated by task 6657:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_cache_noprof+0x3d1/0x6e0
 jfs_fill_super+0xc2/0xd80
 get_tree_bdev_flags+0x431/0x4f0
 vfs_get_tree+0x92/0x2a0
 do_new_mount+0x329/0xa50
 __se_sys_mount+0x31d/0x420
 do_syscall_64+0xe2/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5895:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5c/0x80
 kfree+0x1be/0x650
 generic_shutdown_super+0x135/0x2c0
 kill_block_super+0x44/0x90
 deactivate_locked_super+0xbc/0x130
 cleanup_mnt+0x437/0x4d0
 task_work_run+0x1d9/0x270
 exit_to_user_mode_loop+0xed/0x480
 do_syscall_64+0x2b7/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888115c9fe00
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 148 bytes inside of
 freed 256-byte region [ffff888115c9fe00, ffff888115c9ff00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x115c9e
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0x17ff00000000040(head|node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 017ff00000000040 ffff888100041b40 ffffea000414e780 dead000000000005
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 017ff00000000040 ffff888100041b40 ffffea000414e780 dead000000000005
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 017ff00000000001 ffffea0004572781 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 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 5896, tgid 5896 (syz-executor), ts 70107032505, free_ts 68592317059
 post_alloc_hook+0x228/0x280
 get_page_from_freelist+0x24dc/0x2580
 __alloc_frozen_pages_noprof+0x18d/0x380
 alloc_pages_mpol+0x232/0x4a0
 allocate_slab+0x86/0x3a0
 ___slab_alloc+0xd82/0x1760
 __slab_alloc+0x65/0x100
 __kmalloc_noprof+0x46c/0x7e0
 __register_sysctl_table+0xba1/0x1340
 __devinet_sysctl_register+0x386/0x490
 devinet_sysctl_register+0x187/0x200
 inetdev_init+0x2a4/0x4e0
 inetdev_event+0x30d/0x1610
 notifier_call_chain+0x19d/0x3a0
 register_netdevice+0x15e8/0x1a90
 register_netdev+0x40/0x60
page last free pid 15 tgid 15 stack trace:
 __free_frozen_pages+0xbb0/0xd10
 rcu_core+0xc9e/0x1750
 handle_softirqs+0x22a/0x7c0
 run_ksoftirqd+0x36/0x60
 smpboot_thread_fn+0x541/0xa50
 kthread+0x726/0x8b0
 ret_from_fork+0x51b/0xa40
 ret_from_fork_asm+0x1a/0x30

Memory state around the buggy address:
 ffff888115c9fd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888115c9fe00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888115c9fe80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff888115c9ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888115c9ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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