================================================================== BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:96 [inline] BUG: KASAN: slab-use-after-free in atomic_long_inc_return include/linux/atomic/atomic-instrumented.h:3609 [inline] BUG: KASAN: slab-use-after-free in bch2_dev_get fs/bcachefs/sb-members.h:114 [inline] BUG: KASAN: slab-use-after-free in bch2_get_next_dev+0x28c/0x3b8 fs/bcachefs/sb-members.h:145 Write of size 8 at addr ffff0000c7656040 by task kworker/u9:6/6560 CPU: 1 UID: 0 PID: 6560 Comm: kworker/u9:6 Not tainted 6.17.0-rc1-syzkaller-g8f5ae30d69d7 #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025 Workqueue: bcachefs_journal journal_write_done Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 print_address_description+0xa8/0x238 mm/kasan/report.c:378 print_report+0x68/0x84 mm/kasan/report.c:482 kasan_report+0xb0/0x110 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x264/0x2a4 mm/kasan/generic.c:189 __kasan_check_write+0x20/0x30 mm/kasan/shadow.c:37 instrument_atomic_read_write include/linux/instrumented.h:96 [inline] atomic_long_inc_return include/linux/atomic/atomic-instrumented.h:3609 [inline] bch2_dev_get fs/bcachefs/sb-members.h:114 [inline] bch2_get_next_dev+0x28c/0x3b8 fs/bcachefs/sb-members.h:145 bch2_do_discards+0x2c/0x148 fs/bcachefs/alloc_background.c:1984 journal_write_done+0xd78/0xf2c fs/bcachefs/journal_io.c:1821 process_one_work+0x7e8/0x155c kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x958/0xed8 kernel/workqueue.c:3400 kthread+0x5fc/0x75c kernel/kthread.c:463 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844 Allocated by task 8510: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:68 kasan_save_alloc_info+0x44/0x54 mm/kasan/generic.c:562 poison_kmalloc_redzone mm/kasan/common.c:388 [inline] __kasan_kmalloc+0x9c/0xb4 mm/kasan/common.c:405 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x2a4/0x3fc mm/slub.c:4396 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] __bch2_dev_alloc+0xb8/0x958 fs/bcachefs/super.c:1487 bch2_dev_alloc+0xc0/0x160 fs/bcachefs/super.c:1558 bch2_fs_alloc fs/bcachefs/super.c:1051 [inline] bch2_fs_open+0x1ebc/0x2010 fs/bcachefs/super.c:2433 bch2_fs_get_tree+0x350/0x107c fs/bcachefs/fs.c:2472 vfs_get_tree+0x90/0x28c fs/super.c:1815 do_new_mount+0x278/0x7f4 fs/namespace.c:3805 path_mount+0x5b4/0xde0 fs/namespace.c:4120 do_mount fs/namespace.c:4133 [inline] __do_sys_mount fs/namespace.c:4344 [inline] __se_sys_mount fs/namespace.c:4321 [inline] __arm64_sys_mount+0x3e8/0x468 fs/namespace.c:4321 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x58/0x180 arch/arm64/kernel/entry-common.c:879 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:898 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 Freed by task 6561: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:68 kasan_save_free_info+0x58/0x70 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x74/0x98 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+0x17c/0x474 mm/slub.c:4879 bch2_dev_release+0x20/0x30 fs/bcachefs/super.c:1368 kobject_cleanup lib/kobject.c:689 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x2b0/0x438 lib/kobject.c:737 bch2_dev_free+0x36c/0x414 fs/bcachefs/super.c:1402 bch2_fs_free+0x368/0x4e0 fs/bcachefs/super.c:728 bch2_kill_sb+0x48/0x58 fs/bcachefs/fs.c:2619 deactivate_locked_super+0xc4/0x12c fs/super.c:474 deactivate_super+0xe0/0x100 fs/super.c:507 cleanup_mnt+0x31c/0x3ac fs/namespace.c:1378 __cleanup_mnt+0x20/0x30 fs/namespace.c:1385 task_work_run+0x1dc/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] do_notify_resume+0x174/0x1f4 arch/arm64/kernel/entry-common.c:155 exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:173 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:182 [inline] el0_svc+0xb8/0x180 arch/arm64/kernel/entry-common.c:880 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:898 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 Last potentially related work creation: kasan_save_stack+0x40/0x6c mm/kasan/common.c:47 kasan_record_aux_stack+0xb0/0xc8 mm/kasan/generic.c:548 insert_work+0x54/0x2cc kernel/workqueue.c:2184 __queue_work+0xdb0/0x1210 kernel/workqueue.c:2339 queue_work_on+0xdc/0x18c kernel/workqueue.c:2390 queue_work include/linux/workqueue.h:669 [inline] bch2_dev_do_discards fs/bcachefs/alloc_background.c:1974 [inline] bch2_do_discards+0xb8/0x148 fs/bcachefs/alloc_background.c:1985 journal_write_done+0xd78/0xf2c fs/bcachefs/journal_io.c:1821 process_one_work+0x7e8/0x155c kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x958/0xed8 kernel/workqueue.c:3400 kthread+0x5fc/0x75c kernel/kthread.c:463 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844 Second to last potentially related work creation: kasan_save_stack+0x40/0x6c mm/kasan/common.c:47 kasan_record_aux_stack+0xb0/0xc8 mm/kasan/generic.c:548 insert_work+0x54/0x2cc kernel/workqueue.c:2184 __queue_work+0xdb0/0x1210 kernel/workqueue.c:2339 queue_work_on+0xdc/0x18c kernel/workqueue.c:2390 queue_work include/linux/workqueue.h:669 [inline] bch2_dev_do_discards fs/bcachefs/alloc_background.c:1974 [inline] bch2_do_discards+0xb8/0x148 fs/bcachefs/alloc_background.c:1985 journal_write_done+0xd78/0xf2c fs/bcachefs/journal_io.c:1821 process_one_work+0x7e8/0x155c kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x958/0xed8 kernel/workqueue.c:3400 kthread+0x5fc/0x75c kernel/kthread.c:463 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844 The buggy address belongs to the object at ffff0000c7656000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 64 bytes inside of freed 4096-byte region [ffff0000c7656000, ffff0000c7657000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x107650 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x5ffc00000000040(head|node=0|zone=2|lastcpupid=0x7ff) page_type: f5(slab) raw: 05ffc00000000040 ffff0000c0002140 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000 head: 05ffc00000000040 ffff0000c0002140 dead000000000100 dead000000000122 head: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000 head: 05ffc00000000003 fffffdffc31d9401 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000c7655f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff0000c7655f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff0000c7656000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000c7656080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000c7656100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================