========================= ================================================================== BUG: KASAN: slab-use-after-free in jfs_lazycommit+0x6e1/0xa20 fs/jfs/jfs_txnmgr.c:2738 Read of size 4 at addr ffff888037757894 by task jfsCommit/129 CPU: 0 UID: 0 PID: 129 Comm: jfsCommit Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 Call Trace: 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 jfs_lazycommit+0x6e1/0xa20 fs/jfs/jfs_txnmgr.c:2738 kthread+0x38b/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 12596: 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:409 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:426 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x3d0/0x670 mm/slub.c:5563 _kmalloc_noprof include/linux/slab.h:991 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] jfs_fill_super+0xc2/0xda0 fs/jfs/super.c:452 get_tree_bdev_flags+0x430/0x4f0 fs/super.c:1883 vfs_get_tree+0x92/0x2a0 fs/super.c:1943 fc_mount fs/namespace.c:1282 [inline] do_new_mount_fc fs/namespace.c:3910 [inline] do_new_mount+0x325/0xb00 fs/namespace.c:3986 do_mount fs/namespace.c:4350 [inline] __do_sys_mount fs/namespace.c:4565 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4542 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 5600: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:264 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:296 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2748 [inline] slab_free mm/slub.c:6509 [inline] kfree+0x1c5/0x6d0 mm/slub.c:6802 generic_shutdown_super+0x13d/0x2d0 fs/super.c:751 kill_block_super+0x44/0xa0 fs/super.c:1914 deactivate_locked_super+0xbe/0x110 fs/super.c:586 cleanup_mnt+0x204/0x2a0 fs/namespace.c:1396 task_work_run+0x1d9/0x260 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:70 [inline] exit_to_user_mode_loop+0x204/0x770 kernel/entry/common.c:101 __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:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline] do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888037757800 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 148 bytes inside of freed 256-byte region [ffff888037757800, ffff888037757900) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888037756200 pfn:0x37756 head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x80000000000240(workingset|head|node=0|zone=1) page_type: f5(slab) raw: 0080000000000240 ffff88813ff44b40 ffff88813ff3f988 ffffea0000cc3910 raw: ffff888037756200 0000000000100009 00000000f5000000 0000000000000000 head: 0080000000000240 ffff88813ff44b40 ffff88813ff3f988 ffffea0000cc3910 head: ffff888037756200 0000000000100009 00000000f5000000 0000000000000000 head: 0080000000000001 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 5599, tgid 5599 (syz-executor), ts 85515109940 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871 prep_new_page mm/page_alloc.c:1879 [inline] get_page_from_freelist+0x2591/0x2600 mm/page_alloc.c:3943 __alloc_frozen_pages_noprof+0x230/0x5c0 mm/page_alloc.c:5436 alloc_slab_page mm/slub.c:3347 [inline] allocate_slab+0x7d/0x620 mm/slub.c:3462 new_slab mm/slub.c:3513 [inline] refill_objects+0x2d8/0x350 mm/slub.c:7418 refill_sheaf mm/slub.c:2885 [inline] __pcs_replace_empty_main+0x339/0x690 mm/slub.c:4774 alloc_from_pcs mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:4984 [inline] __kmalloc_cache_noprof+0x46a/0x670 mm/slub.c:5559 _kmalloc_noprof include/linux/slab.h:991 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] kset_create lib/kobject.c:969 [inline] kset_create_and_add+0x5a/0x180 lib/kobject.c:1012 register_queue_kobjects net/core/net-sysfs.c:2085 [inline] netdev_register_kobject+0x1c1/0x350 net/core/net-sysfs.c:2344 register_netdevice+0x1450/0x1ed0 net/core/dev.c:11549 register_vlan_dev+0x3a0/0x850 net/8021q/vlan.c:179 vlan_newlink+0x4b2/0x610 net/8021q/vlan_netlink.c:194 rtnl_newlink_create+0x305/0x7b0 net/core/rtnetlink.c:3974 __rtnl_newlink net/core/rtnetlink.c:4103 [inline] rtnl_newlink+0x166d/0x1c30 net/core/rtnetlink.c:4220 rtnetlink_rcv_msg+0x802/0xc00 net/core/rtnetlink.c:7137 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2579 page last free pid 5601 tgid 5601 ts 85511354018 stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0xf8e/0x1070 mm/page_alloc.c:2962 __slab_free+0x250/0x2a0 mm/slub.c:5823 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:361 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] __do_kmalloc_node mm/slub.c:5413 [inline] __kmalloc_noprof+0x3b4/0x790 mm/slub.c:5439 _kmalloc_noprof include/linux/slab.h:995 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] udp_tunnel_nic_alloc net/ipv4/udp_tunnel_nic.c:758 [inline] udp_tunnel_nic_register net/ipv4/udp_tunnel_nic.c:835 [inline] udp_tunnel_nic_netdevice_event+0x4e6/0x1810 net/ipv4/udp_tunnel_nic.c:933 notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2313 [inline] call_netdevice_notifiers net/core/dev.c:2327 [inline] register_netdevice+0x18bb/0x1ed0 net/core/dev.c:11587 nsim_init_netdevsim drivers/net/netdevsim/netdev.c:1072 [inline] nsim_create+0xbe9/0x1160 drivers/net/netdevsim/netdev.c:1154 __nsim_dev_port_add+0x7f8/0xcd0 drivers/net/netdevsim/dev.c:1434 nsim_dev_port_add_all+0x37/0xf0 drivers/net/netdevsim/dev.c:1495 nsim_drv_probe+0x8c0/0xbc0 drivers/net/netdevsim/dev.c:1656 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x254/0xae0 drivers/base/dd.c:706 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868 driver_probe_device+0x4f/0x240 drivers/base/dd.c:898 Memory state around the buggy address: ffff888037757780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888037757800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888037757880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888037757900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888037757980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================