================================================================== BUG: KASAN: slab-use-after-free in afs_dynroot_readdir_cells fs/afs/dynroot.c:296 [inline] BUG: KASAN: slab-use-after-free in afs_dynroot_readdir+0xd20/0xf50 fs/afs/dynroot.c:352 Read of size 4 at addr ffff888051ad6148 by task syz.3.2385/13649 CPU: 0 UID: 0 PID: 13649 Comm: syz.3.2385 Not tainted 6.15.0-rc1-syzkaller-ga24588245776 #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 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:408 [inline] print_report+0xc3/0x670 mm/kasan/report.c:521 kasan_report+0xe0/0x110 mm/kasan/report.c:634 afs_dynroot_readdir_cells fs/afs/dynroot.c:296 [inline] afs_dynroot_readdir+0xd20/0xf50 fs/afs/dynroot.c:352 iterate_dir+0x293/0xb40 fs/readdir.c:108 __do_sys_getdents fs/readdir.c:322 [inline] __se_sys_getdents fs/readdir.c:308 [inline] __x64_sys_getdents+0x14d/0x2c0 fs/readdir.c:308 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8451b8d169 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f8452ad1038 EFLAGS: 00000246 ORIG_RAX: 000000000000004e RAX: ffffffffffffffda RBX: 00007f8451da5fa0 RCX: 00007f8451b8d169 RDX: 00000000000000b8 RSI: 0000200000001fc0 RDI: 0000000000000005 RBP: 00007f8451c0e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f8451da5fa0 R15: 00007ffee4801628 Allocated by task 13639: 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:377 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] afs_alloc_cell fs/afs/cell.c:137 [inline] afs_lookup_cell+0x61d/0x1680 fs/afs/cell.c:264 afs_dynroot_lookup_cell fs/afs/dynroot.c:111 [inline] afs_dynroot_lookup+0x3d8/0xd60 fs/afs/dynroot.c:159 __lookup_slow+0x24e/0x460 fs/namei.c:1807 lookup_slow fs/namei.c:1824 [inline] walk_component+0x353/0x5b0 fs/namei.c:2128 lookup_last fs/namei.c:2626 [inline] path_lookupat+0x17e/0x780 fs/namei.c:2650 filename_lookup+0x224/0x5f0 fs/namei.c:2679 user_path_at+0x3a/0x60 fs/namei.c:3085 do_mount fs/namespace.c:4216 [inline] __do_sys_mount fs/namespace.c:4430 [inline] __se_sys_mount fs/namespace.c:4407 [inline] __x64_sys_mount+0x1fc/0x310 fs/namespace.c:4407 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 15: 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:247 [inline] __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2389 [inline] slab_free mm/slub.c:4646 [inline] kfree+0x2b6/0x4d0 mm/slub.c:4845 afs_cell_destroy+0x21c/0x310 fs/afs/cell.c:524 rcu_do_batch kernel/rcu/tree.c:2568 [inline] rcu_core+0x799/0x14e0 kernel/rcu/tree.c:2824 handle_softirqs+0x216/0x8e0 kernel/softirq.c:579 run_ksoftirqd kernel/softirq.c:968 [inline] run_ksoftirqd+0x3a/0x60 kernel/softirq.c:960 smpboot_thread_fn+0x3f4/0xae0 kernel/smpboot.c:164 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Last potentially related work creation: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_record_aux_stack+0xb8/0xd0 mm/kasan/generic.c:548 __call_rcu_common.constprop.0+0x9a/0x9f0 kernel/rcu/tree.c:3082 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Second to last potentially related work creation: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_record_aux_stack+0xb8/0xd0 mm/kasan/generic.c:548 insert_work+0x36/0x230 kernel/workqueue.c:2183 __queue_work+0x97e/0x10f0 kernel/workqueue.c:2341 queue_work_on+0x1a4/0x1f0 kernel/workqueue.c:2392 queue_work include/linux/workqueue.h:662 [inline] afs_put_cell.part.0+0x1ab/0x240 fs/afs/cell.c:569 afs_put_cell fs/afs/cell.c:557 [inline] afs_manage_cell_work+0x6de/0x1940 fs/afs/cell.c:859 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff888051ad6000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 328 bytes inside of freed 1024-byte region [ffff888051ad6000, ffff888051ad6400) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x51ad0 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801b442dc0 0000000000000000 dead000000000001 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b442dc0 0000000000000000 dead000000000001 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea000146b401 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 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 6536, tgid 6536 (dhcpcd-run-hook), ts 81620809709, free_ts 73934098494 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1717 prep_new_page mm/page_alloc.c:1725 [inline] get_page_from_freelist+0x1193/0x39b0 mm/page_alloc.c:3652 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4934 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301 alloc_slab_page mm/slub.c:2459 [inline] allocate_slab mm/slub.c:2623 [inline] new_slab+0x23c/0x330 mm/slub.c:2676 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3862 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3952 __slab_alloc_node mm/slub.c:4027 [inline] slab_alloc_node mm/slub.c:4188 [inline] __do_kmalloc_node mm/slub.c:4330 [inline] __kmalloc_noprof+0x2f2/0x510 mm/slub.c:4343 kmalloc_noprof include/linux/slab.h:909 [inline] load_elf_phdrs+0x102/0x210 fs/binfmt_elf.c:532 load_elf_binary+0x14b3/0x4f80 fs/binfmt_elf.c:960 search_binary_handler fs/exec.c:1778 [inline] exec_binprm fs/exec.c:1810 [inline] bprm_execve fs/exec.c:1862 [inline] bprm_execve+0x8c0/0x1650 fs/exec.c:1838 do_execveat_common.isra.0+0x4a5/0x610 fs/exec.c:1968 do_execve fs/exec.c:2042 [inline] __do_sys_execve fs/exec.c:2118 [inline] __se_sys_execve fs/exec.c:2113 [inline] __x64_sys_execve+0x8e/0xb0 fs/exec.c:2113 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 6255 tgid 6255 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1262 [inline] __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2680 vfree+0x176/0x960 mm/vmalloc.c:3383 kcov_put kernel/kcov.c:439 [inline] kcov_put kernel/kcov.c:435 [inline] kcov_close+0x34/0x60 kernel/kcov.c:535 __fput+0x3ff/0xb70 fs/file_table.c:465 task_work_run+0x14d/0x240 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xafb/0x2c30 kernel/exit.c:953 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102 get_signal+0x2673/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [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+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x260 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888051ad6000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888051ad6080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888051ad6100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888051ad6180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888051ad6200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================