================================================================== BUG: KASAN: slab-use-after-free in __ref_is_percpu include/linux/percpu-refcount.h:174 [inline] BUG: KASAN: slab-use-after-free in percpu_ref_put_many include/linux/percpu-refcount.h:332 [inline] BUG: KASAN: slab-use-after-free in percpu_ref_put+0xda/0x250 include/linux/percpu-refcount.h:351 Read of size 8 at addr ffff88804069a0b0 by task kworker/u4:4/1031 CPU: 0 UID: 0 PID: 1031 Comm: kworker/u4:4 Not tainted 6.13.0-syzkaller-09760-g69e858e0b8b2 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Workqueue: loop0 loop_rootcg_workfn Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x169/0x550 mm/kasan/report.c:489 kasan_report+0x143/0x180 mm/kasan/report.c:602 __ref_is_percpu include/linux/percpu-refcount.h:174 [inline] percpu_ref_put_many include/linux/percpu-refcount.h:332 [inline] percpu_ref_put+0xda/0x250 include/linux/percpu-refcount.h:351 blk_update_request+0x5e5/0x1160 block/blk-mq.c:983 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1145 loop_handle_cmd drivers/block/loop.c:1943 [inline] loop_process_work+0x1bc8/0x21c0 drivers/block/loop.c:1961 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317 worker_thread+0x870/0xd30 kernel/workqueue.c:3398 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Allocated by task 5343: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x243/0x390 mm/slub.c:4325 kmalloc_noprof include/linux/slab.h:901 [inline] kzalloc_noprof include/linux/slab.h:1037 [inline] __bch2_dev_alloc+0x57/0xa60 fs/bcachefs/super.c:1299 bch2_dev_alloc+0xd4/0x170 fs/bcachefs/super.c:1366 bch2_fs_alloc fs/bcachefs/super.c:931 [inline] bch2_fs_open+0x2c0d/0x2d50 fs/bcachefs/super.c:2053 bch2_fs_get_tree+0x738/0x1740 fs/bcachefs/fs.c:2190 vfs_get_tree+0x90/0x2b0 fs/super.c:1814 do_new_mount+0x2be/0xb40 fs/namespace.c:3560 do_mount fs/namespace.c:3900 [inline] __do_sys_mount fs/namespace.c:4111 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 5343: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2353 [inline] slab_free mm/slub.c:4609 [inline] kfree+0x196/0x430 mm/slub.c:4757 kobject_cleanup lib/kobject.c:689 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x22f/0x480 lib/kobject.c:737 bch2_fs_free+0x27b/0x3c0 fs/bcachefs/super.c:669 deactivate_locked_super+0xc4/0x130 fs/super.c:473 cleanup_mnt+0x41f/0x4b0 fs/namespace.c:1413 task_work_run+0x24f/0x310 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f Last potentially related work creation: kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47 kasan_record_aux_stack+0xaa/0xc0 mm/kasan/generic.c:548 insert_work+0x3e/0x330 kernel/workqueue.c:2183 __queue_work+0xc8b/0xf50 kernel/workqueue.c:2339 queue_work_on+0x1c2/0x380 kernel/workqueue.c:2390 queue_work include/linux/workqueue.h:662 [inline] bch2_dev_do_invalidates+0x17a/0x1f0 fs/bcachefs/alloc_background.c:2193 bch2_do_invalidates+0x29/0x60 fs/bcachefs/alloc_background.c:2204 __bch2_fs_read_write+0x386/0x3b0 fs/bcachefs/super.c:502 bch2_fs_initialize+0xa45/0x1610 fs/bcachefs/recovery.c:1133 bch2_fs_start+0x36d/0x610 fs/bcachefs/super.c:1031 bch2_fs_get_tree+0xd8d/0x1740 fs/bcachefs/fs.c:2203 vfs_get_tree+0x90/0x2b0 fs/super.c:1814 do_new_mount+0x2be/0xb40 fs/namespace.c:3560 do_mount fs/namespace.c:3900 [inline] __do_sys_mount fs/namespace.c:4111 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Second to last potentially related work creation: kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47 kasan_record_aux_stack+0xaa/0xc0 mm/kasan/generic.c:548 insert_work+0x3e/0x330 kernel/workqueue.c:2183 __queue_work+0xc8b/0xf50 kernel/workqueue.c:2339 queue_work_on+0x1c2/0x380 kernel/workqueue.c:2390 queue_work include/linux/workqueue.h:662 [inline] bch2_dev_do_discards+0x17a/0x1f0 fs/bcachefs/alloc_background.c:1949 bch2_do_discards+0x29/0x60 fs/bcachefs/alloc_background.c:1960 __bch2_fs_read_write+0x37e/0x3b0 fs/bcachefs/super.c:501 bch2_fs_initialize+0xa45/0x1610 fs/bcachefs/recovery.c:1133 bch2_fs_start+0x36d/0x610 fs/bcachefs/super.c:1031 bch2_fs_get_tree+0xd8d/0x1740 fs/bcachefs/fs.c:2203 vfs_get_tree+0x90/0x2b0 fs/super.c:1814 do_new_mount+0x2be/0xb40 fs/namespace.c:3560 do_mount fs/namespace.c:3900 [inline] __do_sys_mount fs/namespace.c:4111 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88804069a000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 176 bytes inside of freed 4096-byte region [ffff88804069a000, ffff88804069b000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x40698 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 anon flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 04fff00000000040 ffff88801ac42140 0000000000000000 dead000000000001 raw: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000 head: 04fff00000000040 ffff88801ac42140 0000000000000000 dead000000000001 head: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000 head: 04fff00000000003 ffffea000101a601 ffffffffffffffff 0000000000000000 head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5024, tgid 5024 (dhcpcd), ts 43728168803, free_ts 43717580313 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1551 prep_new_page mm/page_alloc.c:1559 [inline] get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3477 __alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4739 alloc_pages_mpol+0x311/0x660 mm/mempolicy.c:2270 alloc_slab_page mm/slub.c:2423 [inline] allocate_slab+0x8f/0x3a0 mm/slub.c:2587 new_slab mm/slub.c:2640 [inline] ___slab_alloc+0xc27/0x14a0 mm/slub.c:3826 __slab_alloc+0x58/0xa0 mm/slub.c:3916 __slab_alloc_node mm/slub.c:3991 [inline] slab_alloc_node mm/slub.c:4152 [inline] __kmalloc_cache_noprof+0x27b/0x390 mm/slub.c:4320 kmalloc_noprof include/linux/slab.h:901 [inline] kzalloc_noprof include/linux/slab.h:1037 [inline] kernfs_iop_get_link+0x67/0x5a0 fs/kernfs/symlink.c:135 pick_link+0x631/0xd50 step_into+0xcd2/0x10b0 fs/namei.c:1984 walk_component fs/namei.c:2120 [inline] link_path_walk+0x7b7/0xea0 fs/namei.c:2479 path_openat+0x266/0x3590 fs/namei.c:3985 do_filp_open+0x27f/0x4e0 fs/namei.c:4016 do_sys_openat2+0x13e/0x1d0 fs/open.c:1427 do_sys_open fs/open.c:1442 [inline] __do_sys_openat fs/open.c:1458 [inline] __se_sys_openat fs/open.c:1453 [inline] __x64_sys_openat+0x247/0x2a0 fs/open.c:1453 page last free pid 5024 tgid 5024 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1127 [inline] free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2660 discard_slab mm/slub.c:2684 [inline] __put_partials+0x160/0x1c0 mm/slub.c:3153 put_cpu_partial+0x17c/0x250 mm/slub.c:3228 __slab_free+0x290/0x380 mm/slub.c:4479 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4115 [inline] slab_alloc_node mm/slub.c:4164 [inline] kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4171 getname_flags+0xb7/0x540 fs/namei.c:139 do_readlinkat+0xd8/0x3a0 fs/stat.c:561 __do_sys_readlink fs/stat.c:599 [inline] __se_sys_readlink fs/stat.c:596 [inline] __x64_sys_readlink+0x7f/0x90 fs/stat.c:596 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888040699f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88804069a000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88804069a080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88804069a100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88804069a180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================