================================================================== BUG: KASAN: slab-use-after-free in jfs_lazycommit+0xa46/0xb30 fs/jfs/jfs_txnmgr.c:2736 Read of size 4 at addr ffff888074d9e094 by task jfsCommit/109 CPU: 0 UID: 0 PID: 109 Comm: jfsCommit Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 jfs_lazycommit+0xa46/0xb30 fs/jfs/jfs_txnmgr.c:2736 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 6218: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:388 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:405 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] jfs_fill_super+0xca/0x1040 fs/jfs/super.c:452 get_tree_bdev_flags+0x38c/0x620 fs/super.c:1692 vfs_get_tree+0x8e/0x340 fs/super.c:1815 do_new_mount fs/namespace.c:3808 [inline] path_mount+0x1513/0x2000 fs/namespace.c:4123 do_mount fs/namespace.c:4136 [inline] __do_sys_mount fs/namespace.c:4347 [inline] __se_sys_mount fs/namespace.c:4324 [inline] __x64_sys_mount+0x28d/0x310 fs/namespace.c:4324 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 5861: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x60/0x70 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2417 [inline] slab_free mm/slub.c:4680 [inline] kfree+0x2b4/0x4d0 mm/slub.c:4879 generic_shutdown_super+0x156/0x390 fs/super.c:643 kill_block_super+0x3b/0x90 fs/super.c:1766 deactivate_locked_super+0xc1/0x1a0 fs/super.c:474 deactivate_super fs/super.c:507 [inline] deactivate_super+0xde/0x100 fs/super.c:503 cleanup_mnt+0x225/0x450 fs/namespace.c:1375 task_work_run+0x150/0x240 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888074d9e000 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 148 bytes inside of freed 256-byte region [ffff888074d9e000, ffff888074d9e100) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888074d9f600 pfn:0x74d9e head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 ksm flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801b841b40 ffffea0000ca2500 0000000000000003 raw: ffff888074d9f600 000000000010000f 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b841b40 ffffea0000ca2500 0000000000000003 head: ffff888074d9f600 000000000010000f 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffea0001d36781 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 6037, tgid 6036 (syz.5.6), ts 95062363273, free_ts 95060638843 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1851 prep_new_page mm/page_alloc.c:1859 [inline] get_page_from_freelist+0x132b/0x38e0 mm/page_alloc.c:3858 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:5148 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:2487 [inline] allocate_slab mm/slub.c:2655 [inline] new_slab+0x247/0x330 mm/slub.c:2709 ___slab_alloc+0xcf2/0x1740 mm/slub.c:3891 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3981 __slab_alloc_node mm/slub.c:4056 [inline] slab_alloc_node mm/slub.c:4217 [inline] __do_kmalloc_node mm/slub.c:4364 [inline] __kvmalloc_node_noprof+0x3b1/0x620 mm/slub.c:5052 kvmalloc_array_node_noprof include/linux/slab.h:1065 [inline] io_alloc_cache_init+0x33/0x170 io_uring/alloc_cache.c:25 io_ring_ctx_alloc io_uring/io_uring.c:329 [inline] io_uring_create io_uring/io_uring.c:3743 [inline] io_uring_setup+0x5e1/0x2120 io_uring/io_uring.c:3890 __do_sys_io_uring_setup io_uring/io_uring.c:3924 [inline] __se_sys_io_uring_setup io_uring/io_uring.c:3915 [inline] __x64_sys_io_uring_setup+0xc2/0x170 io_uring/io_uring.c:3915 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 5875 tgid 5875 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0x7d5/0x10f0 mm/page_alloc.c:2895 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:340 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4180 [inline] slab_alloc_node mm/slub.c:4229 [inline] kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4236 locks_alloc_lock fs/locks.c:275 [inline] flock_lock_inode+0xbe5/0x1030 fs/locks.c:1091 flock_lock_inode_wait fs/locks.c:2084 [inline] locks_lock_inode_wait+0x1da/0x490 fs/locks.c:2111 locks_lock_file_wait include/linux/filelock.h:427 [inline] __do_sys_flock+0x446/0x520 fs/locks.c:2179 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888074d9df80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888074d9e000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888074d9e080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888074d9e100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888074d9e180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================