================================================================== BUG: KASAN: slab-use-after-free in jfs_lazycommit+0x74b/0xa90 fs/jfs/jfs_txnmgr.c:2737 Read of size 4 at addr ffff88803dc9b494 by task jfsCommit/115 CPU: 0 UID: 0 PID: 115 Comm: jfsCommit Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: 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+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 12810: 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:400 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417 kasan_kmalloc include/linux/kasan.h:262 [inline] __kmalloc_cache_noprof+0x3d5/0x6f0 mm/slub.c:5723 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:1691 vfs_get_tree+0x92/0x2b0 fs/super.c:1751 fc_mount fs/namespace.c:1208 [inline] do_new_mount_fc fs/namespace.c:3651 [inline] do_new_mount+0x302/0x9e0 fs/namespace.c:3725 do_mount fs/namespace.c:4048 [inline] __do_sys_mount fs/namespace.c:4236 [inline] __se_sys_mount+0x313/0x410 fs/namespace.c:4213 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 6239: 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:587 kasan_save_free_info mm/kasan/kasan.h:406 [inline] 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:2507 [inline] slab_free mm/slub.c:6557 [inline] kfree+0x19a/0x6d0 mm/slub.c:6765 generic_shutdown_super+0x135/0x2c0 fs/super.c:642 kill_block_super+0x44/0x90 fs/super.c:1722 deactivate_locked_super+0xbc/0x130 fs/super.c:473 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1327 task_work_run+0x1d4/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xe9/0x130 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+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88803dc9b400 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 148 bytes inside of freed 256-byte region [ffff88803dc9b400, ffff88803dc9b500) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3dc9a 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 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813fe26b40 dead000000000122 0000000000000000 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffea0000f72681 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 12808, tgid 12802 (syz.0.1179), ts 564799038091, free_ts 511017451572 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3884 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:3023 [inline] allocate_slab+0x96/0x3a0 mm/slub.c:3196 new_slab mm/slub.c:3250 [inline] ___slab_alloc+0xe94/0x1920 mm/slub.c:4626 __slab_alloc+0x65/0x100 mm/slub.c:4745 __slab_alloc_node mm/slub.c:4821 [inline] slab_alloc_node mm/slub.c:5232 [inline] __do_kmalloc_node mm/slub.c:5601 [inline] __kmalloc_noprof+0x471/0x7f0 mm/slub.c:5614 kmalloc_noprof include/linux/slab.h:961 [inline] io_cache_alloc_new+0x40/0x100 io_uring/alloc_cache.c:40 io_cache_alloc io_uring/alloc_cache.h:59 [inline] io_uring_alloc_async_data io_uring/io_uring.h:323 [inline] io_rw_alloc_async io_uring/rw.c:202 [inline] __io_prep_rw+0x23f/0xe20 io_uring/rw.c:261 io_prep_rw io_uring/rw.c:322 [inline] io_prep_rwv+0x91/0x3e0 io_uring/rw.c:344 io_init_req io_uring/io_uring.c:2261 [inline] io_submit_sqe io_uring/io_uring.c:2308 [inline] io_submit_sqes+0x935/0x1e60 io_uring/io_uring.c:2460 __do_sys_io_uring_enter io_uring/io_uring.c:3527 [inline] __se_sys_io_uring_enter+0x2e0/0x2b80 io_uring/io_uring.c:3466 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 page last free pid 43 tgid 43 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2906 vfree+0x25a/0x400 mm/vmalloc.c:3440 delayed_vfree_work+0x55/0x80 mm/vmalloc.c:3359 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff88803dc9b380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88803dc9b400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88803dc9b480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88803dc9b500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88803dc9b580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================