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BUG: KASAN: slab-use-after-free in jfs_lazycommit+0x74b/0xa90 fs/jfs/jfs_txnmgr.c:2737
Read of size 4 at addr ffff888061b6b294 by task jfsCommit/114

CPU: 1 UID: 0 PID: 114 Comm: jfsCommit Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 jfs_lazycommit+0x74b/0xa90 fs/jfs/jfs_txnmgr.c:2737
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>

Allocated by task 20866:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 poison_kmalloc_redzone mm/kasan/common.c:397 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414
 kasan_kmalloc include/linux/kasan.h:262 [inline]
 __kmalloc_cache_noprof+0x3e2/0x700 mm/slub.c:5771
 kmalloc_noprof include/linux/slab.h:957 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 jfs_fill_super+0xc2/0xd80 fs/jfs/super.c:452
 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1699
 vfs_get_tree+0x92/0x2b0 fs/super.c:1759
 fc_mount fs/namespace.c:1209 [inline]
 do_new_mount_fc fs/namespace.c:3652 [inline]
 do_new_mount+0x302/0xa10 fs/namespace.c:3728
 do_mount fs/namespace.c:4051 [inline]
 __do_sys_mount fs/namespace.c:4240 [inline]
 __se_sys_mount+0x313/0x410 fs/namespace.c:4217
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 19957:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:252 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2540 [inline]
 slab_free mm/slub.c:6663 [inline]
 kfree+0x1c0/0x680 mm/slub.c:6871
 generic_shutdown_super+0x135/0x2c0 fs/super.c:643
 kill_block_super+0x44/0x90 fs/super.c:1730
 deactivate_locked_super+0xbc/0x130 fs/super.c:474
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1328
 task_work_run+0x1d4/0x260 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:44 [inline]
 exit_to_user_mode_loop+0xff/0x4f0 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2e9/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888061b6b200
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 148 bytes inside of
 freed 256-byte region [ffff888061b6b200, ffff888061b6b300)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x61b6a
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88813fe26b40 ffffea0001f4f480 dead000000000004
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813fe26b40 ffffea0001f4f480 dead000000000004
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000001 ffffea000186da81 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 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 8168, tgid 8168 (syz-executor), ts 371013561037, free_ts 364629167783
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x234/0x290 mm/page_alloc.c:1846
 prep_new_page mm/page_alloc.c:1854 [inline]
 get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3915
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486
 alloc_slab_page mm/slub.c:3075 [inline]
 allocate_slab+0x86/0x3b0 mm/slub.c:3248
 new_slab mm/slub.c:3302 [inline]
 ___slab_alloc+0xf56/0x1990 mm/slub.c:4651
 __slab_alloc+0x65/0x100 mm/slub.c:4774
 __slab_alloc_node mm/slub.c:4850 [inline]
 slab_alloc_node mm/slub.c:5246 [inline]
 __do_kmalloc_node mm/slub.c:5651 [inline]
 __kmalloc_noprof+0x47d/0x800 mm/slub.c:5664
 kmalloc_noprof include/linux/slab.h:961 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 new_dir fs/proc/proc_sysctl.c:966 [inline]
 get_subdir fs/proc/proc_sysctl.c:1010 [inline]
 sysctl_mkdir_p fs/proc/proc_sysctl.c:1320 [inline]
 __register_sysctl_table+0xba1/0x1340 fs/proc/proc_sysctl.c:1395
 neigh_sysctl_register+0x9a2/0xa80 net/core/neighbour.c:3886
 addrconf_sysctl_register+0xb3/0x1c0 net/ipv6/addrconf.c:7367
 ipv6_add_dev+0xd44/0x1410 net/ipv6/addrconf.c:460
 addrconf_notify+0x771/0x1080 net/ipv6/addrconf.c:3650
 notifier_call_chain+0x19d/0x3d0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2269 [inline]
 call_netdevice_notifiers net/core/dev.c:2283 [inline]
 register_netdevice+0x15fd/0x1b00 net/core/dev.c:11422
 veth_newlink+0x5d4/0xa60 drivers/net/veth.c:1886
page last free pid 8231 tgid 8231 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0xbc8/0xd30 mm/page_alloc.c:2943
 mm_free_pgd kernel/fork.c:541 [inline]
 __mmdrop+0xb6/0x750 kernel/fork.c:683
 exit_mm+0x1da/0x2c0 kernel/exit.c:581
 do_exit+0x650/0x2300 kernel/exit.c:958
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1111
 __do_sys_exit_group kernel/exit.c:1122 [inline]
 __se_sys_exit_group kernel/exit.c:1120 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1120
 __pfx_syscall_get_nr+0x0/0x10 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888061b6b180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888061b6b200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888061b6b280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff888061b6b300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888061b6b380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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