================================================================== BUG: KASAN: use-after-free in arch_atomic_read arch/x86/include/asm/atomic.h:29 [inline] BUG: KASAN: use-after-free in atomic_read include/linux/atomic/atomic-instrumented.h:28 [inline] BUG: KASAN: use-after-free in kernfs_get+0x8a/0x90 fs/kernfs/dir.c:519 Read of size 4 at addr ffff888122823640 by task kworker/0:2/299 CPU: 0 PID: 299 Comm: kworker/0:2 Tainted: G W 6.1.78-syzkaller-00046-g6aaa06c15d9b #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 Workqueue: events flush_stashed_error_work Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x151/0x1b7 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:316 [inline] print_report+0x158/0x4e0 mm/kasan/report.c:427 kasan_report+0x13c/0x170 mm/kasan/report.c:531 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:350 arch_atomic_read arch/x86/include/asm/atomic.h:29 [inline] atomic_read include/linux/atomic/atomic-instrumented.h:28 [inline] kernfs_get+0x8a/0x90 fs/kernfs/dir.c:519 sysfs_notify+0x9a/0xd0 fs/sysfs/file.c:187 ext4_notify_error_sysfs+0x25/0x30 fs/ext4/sysfs.c:518 flush_stashed_error_work+0x2fe/0x320 process_one_work+0x73d/0xcb0 kernel/workqueue.c:2299 worker_thread+0xa60/0x1260 kernel/workqueue.c:2446 kthread+0x26d/0x300 kernel/kthread.c:386 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 Allocated by task 4927: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 kasan_save_alloc_info+0x1f/0x30 mm/kasan/generic.c:505 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:333 kasan_slab_alloc include/linux/kasan.h:202 [inline] slab_post_alloc_hook+0x53/0x2c0 mm/slab.h:768 slab_alloc_node mm/slub.c:3421 [inline] slab_alloc mm/slub.c:3429 [inline] __kmem_cache_alloc_lru mm/slub.c:3436 [inline] kmem_cache_alloc+0x175/0x2c0 mm/slub.c:3445 kmem_cache_zalloc include/linux/slab.h:679 [inline] __kernfs_new_node+0xdb/0x700 fs/kernfs/dir.c:608 kernfs_new_node+0x130/0x230 fs/kernfs/dir.c:684 kernfs_create_dir_ns+0x44/0x130 fs/kernfs/dir.c:1035 sysfs_create_dir_ns+0x185/0x390 fs/sysfs/dir.c:59 create_dir lib/kobject.c:63 [inline] kobject_add_internal+0x635/0xbf0 lib/kobject.c:231 kobject_add_varg lib/kobject.c:366 [inline] kobject_init_and_add+0x120/0x190 lib/kobject.c:449 ext4_register_sysfs+0xbf/0x2c0 fs/ext4/sysfs.c:531 __ext4_fill_super fs/ext4/super.c:5495 [inline] ext4_fill_super+0x7930/0x8460 fs/ext4/super.c:5651 get_tree_bdev+0x440/0x680 fs/super.c:1357 ext4_get_tree+0x1c/0x20 fs/ext4/super.c:5681 vfs_get_tree+0x88/0x290 fs/super.c:1564 do_new_mount+0x2ba/0xb30 fs/namespace.c:3051 path_mount+0x671/0x1070 fs/namespace.c:3381 do_mount fs/namespace.c:3394 [inline] __do_sys_mount fs/namespace.c:3602 [inline] __se_sys_mount+0x2c4/0x3b0 fs/namespace.c:3579 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3579 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 4071: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:516 ____kasan_slab_free+0x131/0x180 mm/kasan/common.c:241 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:249 kasan_slab_free include/linux/kasan.h:178 [inline] slab_free_hook mm/slub.c:1745 [inline] slab_free_freelist_hook mm/slub.c:1771 [inline] slab_free mm/slub.c:3684 [inline] kmem_cache_free+0x291/0x510 mm/slub.c:3706 kernfs_put+0x392/0x520 fs/kernfs/dir.c:562 sysfs_put include/linux/sysfs.h:657 [inline] __kobject_del+0x10f/0x300 lib/kobject.c:597 kobject_del+0x45/0x60 lib/kobject.c:619 ext4_unregister_sysfs+0x91/0xa0 fs/ext4/sysfs.c:565 ext4_put_super+0x7d/0xd60 fs/ext4/super.c:1215 generic_shutdown_super+0x14f/0x370 fs/super.c:503 kill_block_super+0x7e/0xe0 fs/super.c:1461 deactivate_locked_super+0xad/0x110 fs/super.c:334 deactivate_super+0xbe/0xf0 fs/super.c:365 cleanup_mnt+0x485/0x510 fs/namespace.c:1186 __cleanup_mnt+0x19/0x20 fs/namespace.c:1193 task_work_run+0x24d/0x2e0 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0x94/0xa0 kernel/entry/common.c:171 exit_to_user_mode_prepare+0x5a/0xa0 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:297 do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x63/0xcd The buggy address belongs to the object at ffff888122823640 which belongs to the cache kernfs_node_cache of size 136 The buggy address is located 0 bytes inside of 136-byte region [ffff888122823640, ffff8881228236c8) The buggy address belongs to the physical page: page:ffffea00048a08c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x122823 flags: 0x4000000000000200(slab|zone=1) raw: 4000000000000200 0000000000000000 dead000000000122 ffff8881002a0900 raw: 0000000000000000 0000000000140014 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 4927, tgid 4926 (syz.1.1637), ts 178309437558, free_ts 178309326420 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x213/0x220 mm/page_alloc.c:2590 prep_new_page+0x1b/0x110 mm/page_alloc.c:2597 get_page_from_freelist+0x27ea/0x2870 mm/page_alloc.c:4425 __alloc_pages+0x3a1/0x780 mm/page_alloc.c:5712 alloc_slab_page+0x6c/0xf0 allocate_slab mm/slub.c:1962 [inline] new_slab+0x90/0x3e0 mm/slub.c:2015 ___slab_alloc+0x6f9/0xb80 mm/slub.c:3203 __slab_alloc+0x5d/0xa0 mm/slub.c:3302 slab_alloc_node mm/slub.c:3387 [inline] slab_alloc mm/slub.c:3429 [inline] __kmem_cache_alloc_lru mm/slub.c:3436 [inline] kmem_cache_alloc+0x1b9/0x2c0 mm/slub.c:3445 kmem_cache_zalloc include/linux/slab.h:679 [inline] __kernfs_new_node+0xdb/0x700 fs/kernfs/dir.c:608 kernfs_new_node+0x130/0x230 fs/kernfs/dir.c:684 __kernfs_create_file+0x4a/0x270 fs/kernfs/file.c:1043 sysfs_add_file_mode_ns+0x1c8/0x270 fs/sysfs/file.c:294 create_files fs/sysfs/group.c:64 [inline] internal_create_group+0x545/0xed0 fs/sysfs/group.c:148 sysfs_create_group+0x1f/0x30 fs/sysfs/group.c:174 loop_sysfs_init drivers/block/loop.c:744 [inline] loop_configure+0xe8e/0x1550 drivers/block/loop.c:1095 page last free stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] free_pages_prepare mm/page_alloc.c:1498 [inline] free_pcp_prepare mm/page_alloc.c:1572 [inline] free_unref_page_prepare+0x83d/0x850 mm/page_alloc.c:3498 free_unref_page+0xb2/0x5c0 mm/page_alloc.c:3594 free_the_page mm/page_alloc.c:798 [inline] __free_pages+0x61/0xf0 mm/page_alloc.c:5801 free_pages+0x7c/0x90 mm/page_alloc.c:5812 tlb_batch_list_free mm/mmu_gather.c:75 [inline] tlb_finish_mmu+0x311/0x3f0 mm/mmu_gather.c:364 unmap_region+0x2c1/0x310 mm/mmap.c:2405 do_mas_align_munmap+0xd05/0x1400 mm/mmap.c:2672 do_mas_munmap+0x23e/0x2b0 mm/mmap.c:2730 __vm_munmap+0x263/0x3a0 mm/mmap.c:3020 __do_sys_munmap mm/mmap.c:3046 [inline] __se_sys_munmap mm/mmap.c:3042 [inline] __x64_sys_munmap+0x6b/0x80 mm/mmap.c:3042 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd Memory state around the buggy address: ffff888122823500: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fa ffff888122823580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888122823600: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ^ ffff888122823680: fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc ffff888122823700: fc fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== general protection fault, probably for non-canonical address 0xe0d43c2a60000206: 0000 [#1] PREEMPT SMP KASAN KASAN: maybe wild-memory-access in range [0x06a2015300001030-0x06a2015300001037] CPU: 0 PID: 299 Comm: kworker/0:2 Tainted: G B W 6.1.78-syzkaller-00046-g6aaa06c15d9b #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 Workqueue: events flush_stashed_error_work RIP: 0010:kernfs_root fs/kernfs/kernfs-internal.h:68 [inline] RIP: 0010:kernfs_find_and_get_ns+0x52/0x110 fs/kernfs/dir.c:895 Code: 08 48 89 f8 48 c1 e8 03 42 80 3c 30 00 74 05 e8 b4 01 d4 ff 49 8b 5d 08 48 85 db 49 0f 44 dd 48 83 c3 50 48 89 d8 48 c1 e8 03 <42> 80 3c 30 00 74 08 48 89 df e8 8f 01 d4 ff 4c 8b 33 49 83 c6 60 RSP: 0018:ffffc9000939fc68 EFLAGS: 00010207 RAX: 00d4402a60000206 RBX: 06a2015300001037 RCX: ffffffff81e87ddc RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff888122823648 RBP: ffffc9000939fc90 R08: dffffc0000000000 R09: 0000000000000003 R10: ffffffffffffffff R11: dffffc0000000001 R12: ffffffff85b490a0 R13: ffff888122823640 R14: dffffc0000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000128ac0000 CR4: 00000000003526b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kernfs_find_and_get include/linux/kernfs.h:614 [inline] sysfs_notify+0x73/0xd0 fs/sysfs/file.c:190 ext4_notify_error_sysfs+0x25/0x30 fs/ext4/sysfs.c:518 flush_stashed_error_work+0x2fe/0x320 process_one_work+0x73d/0xcb0 kernel/workqueue.c:2299 worker_thread+0xa60/0x1260 kernel/workqueue.c:2446 kthread+0x26d/0x300 kernel/kthread.c:386 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:kernfs_root fs/kernfs/kernfs-internal.h:68 [inline] RIP: 0010:kernfs_find_and_get_ns+0x52/0x110 fs/kernfs/dir.c:895 Code: 08 48 89 f8 48 c1 e8 03 42 80 3c 30 00 74 05 e8 b4 01 d4 ff 49 8b 5d 08 48 85 db 49 0f 44 dd 48 83 c3 50 48 89 d8 48 c1 e8 03 <42> 80 3c 30 00 74 08 48 89 df e8 8f 01 d4 ff 4c 8b 33 49 83 c6 60 RSP: 0018:ffffc9000939fc68 EFLAGS: 00010207 RAX: 00d4402a60000206 RBX: 06a2015300001037 RCX: ffffffff81e87ddc RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff888122823648 RBP: ffffc9000939fc90 R08: dffffc0000000000 R09: 0000000000000003 R10: ffffffffffffffff R11: dffffc0000000001 R12: ffffffff85b490a0 R13: ffff888122823640 R14: dffffc0000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f86d2525d58 CR3: 0000000118feb000 CR4: 00000000003526b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 08 48 89 or %cl,-0x77(%rax) 3: f8 clc 4: 48 c1 e8 03 shr $0x3,%rax 8: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1) d: 74 05 je 0x14 f: e8 b4 01 d4 ff call 0xffd401c8 14: 49 8b 5d 08 mov 0x8(%r13),%rbx 18: 48 85 db test %rbx,%rbx 1b: 49 0f 44 dd cmove %r13,%rbx 1f: 48 83 c3 50 add $0x50,%rbx 23: 48 89 d8 mov %rbx,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1) <-- trapping instruction 2f: 74 08 je 0x39 31: 48 89 df mov %rbx,%rdi 34: e8 8f 01 d4 ff call 0xffd401c8 39: 4c 8b 33 mov (%rbx),%r14 3c: 49 83 c6 60 add $0x60,%r14