================================================================== BUG: KASAN: use-after-free in fast_dput+0x1f2/0x2a0 fs/dcache.c:750 Read of size 4 at addr ffff8881090f5aa0 by task syz-executor/290 CPU: 1 PID: 290 Comm: syz-executor Tainted: G W 5.10.226-syzkaller-00709-ge5e5644ea27f #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118 print_address_description+0x81/0x3b0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:435 [inline] kasan_report+0x179/0x1c0 mm/kasan/report.c:452 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308 fast_dput+0x1f2/0x2a0 fs/dcache.c:750 dput+0x21/0x80 fs/dcache.c:870 incfs_free_mount_info+0x60/0x210 fs/incfs/data_mgmt.c:166 incfs_kill_sb+0x1c2/0x220 fs/incfs/vfs.c:1979 deactivate_locked_super+0xad/0x110 fs/super.c:335 deactivate_super+0xbe/0xf0 fs/super.c:366 cleanup_mnt+0x45c/0x510 fs/namespace.c:1118 __cleanup_mnt+0x19/0x20 fs/namespace.c:1125 task_work_run+0x129/0x190 kernel/task_work.c:189 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop+0xbf/0xd0 kernel/entry/common.c:172 exit_to_user_mode_prepare kernel/entry/common.c:199 [inline] syscall_exit_to_user_mode+0xa2/0x1a0 kernel/entry/common.c:274 do_syscall_64+0x40/0x70 arch/x86/entry/common.c:56 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f33a13cf327 Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8 RSP: 002b:00007fff52803668 EFLAGS: 00000206 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f33a1440134 RCX: 00007f33a13cf327 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fff52803720 RBP: 00007fff52803720 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000206 R12: 00007fff528047a0 R13: 00007f33a1440134 R14: 00000000000072dd R15: 00007fff528047e0 Allocated by task 320: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:430 [inline] __kasan_slab_alloc+0xb1/0xe0 mm/kasan/common.c:463 kasan_slab_alloc include/linux/kasan.h:244 [inline] slab_post_alloc_hook+0x61/0x2f0 mm/slab.h:583 slab_alloc_node mm/slub.c:2947 [inline] slab_alloc mm/slub.c:2955 [inline] kmem_cache_alloc+0x168/0x2e0 mm/slub.c:2960 __d_alloc+0x2d/0x6c0 fs/dcache.c:1714 d_alloc fs/dcache.c:1793 [inline] d_alloc_parallel+0xec/0x1370 fs/dcache.c:2547 __lookup_slow+0x154/0x400 fs/namei.c:1625 lookup_one_len+0x180/0x2c0 fs/namei.c:2656 incfs_lookup_dentry+0x5f/0xb0 fs/incfs/data_mgmt.c:210 open_or_create_special_dir+0x4f/0x1d0 fs/incfs/vfs.c:469 incfs_mount_fs+0x48d/0xa10 fs/incfs/vfs.c:1867 legacy_get_tree+0xf1/0x190 fs/fs_context.c:593 vfs_get_tree+0x88/0x290 fs/super.c:1570 do_new_mount+0x2ba/0xb30 fs/namespace.c:2910 path_mount+0x56f/0xcb0 fs/namespace.c:3240 do_mount fs/namespace.c:3253 [inline] __do_sys_mount fs/namespace.c:3461 [inline] __se_sys_mount+0x2c4/0x3b0 fs/namespace.c:3438 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3438 do_syscall_64+0x34/0x70 entry_SYSCALL_64_after_hwframe+0x61/0xcb Freed by task 391: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:45 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370 ____kasan_slab_free+0x121/0x160 mm/kasan/common.c:362 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370 kasan_slab_free include/linux/kasan.h:220 [inline] slab_free_hook mm/slub.c:1595 [inline] slab_free_freelist_hook+0xc0/0x190 mm/slub.c:1621 slab_free mm/slub.c:3203 [inline] kmem_cache_free+0xa9/0x1e0 mm/slub.c:3219 __d_free+0x23/0x30 fs/dcache.c:271 rcu_do_batch+0x597/0xc40 kernel/rcu/tree.c:2494 rcu_core+0x5ad/0xe40 kernel/rcu/tree.c:2735 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2748 __do_softirq+0x268/0x5bb kernel/softirq.c:309 Last potentially related work creation: kasan_save_stack+0x3b/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xd3/0x100 mm/kasan/generic.c:348 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358 __call_rcu kernel/rcu/tree.c:2976 [inline] call_rcu+0x135/0x11f0 kernel/rcu/tree.c:3050 dentry_free+0xbf/0x160 __dentry_kill+0x505/0x650 fs/dcache.c:597 dentry_kill+0xc0/0x2a0 dput+0x40/0x80 fs/dcache.c:883 incfs_free_mount_info+0x60/0x210 fs/incfs/data_mgmt.c:166 incfs_kill_sb+0x1c2/0x220 fs/incfs/vfs.c:1979 deactivate_locked_super+0xad/0x110 fs/super.c:335 deactivate_super+0xbe/0xf0 fs/super.c:366 cleanup_mnt+0x45c/0x510 fs/namespace.c:1118 __cleanup_mnt+0x19/0x20 fs/namespace.c:1125 task_work_run+0x129/0x190 kernel/task_work.c:189 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop+0xbf/0xd0 kernel/entry/common.c:172 exit_to_user_mode_prepare kernel/entry/common.c:199 [inline] syscall_exit_to_user_mode+0xa2/0x1a0 kernel/entry/common.c:274 do_syscall_64+0x40/0x70 arch/x86/entry/common.c:56 entry_SYSCALL_64_after_hwframe+0x61/0xcb Second to last potentially related work creation: kasan_save_stack+0x3b/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xd3/0x100 mm/kasan/generic.c:348 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358 __call_rcu kernel/rcu/tree.c:2976 [inline] call_rcu+0x135/0x11f0 kernel/rcu/tree.c:3050 dentry_free+0xbf/0x160 __dentry_kill+0x505/0x650 fs/dcache.c:597 dentry_kill+0xc0/0x2a0 dput+0x40/0x80 fs/dcache.c:883 handle_mounts fs/namei.c:1485 [inline] step_into+0x3d0/0xec0 fs/namei.c:1782 walk_component+0x359/0x610 fs/namei.c:1958 link_path_walk+0x5c7/0xbd0 path_openat+0x26a/0x3000 fs/namei.c:3505 do_file_open_root+0x348/0x740 fs/namei.c:3564 file_open_root+0x25b/0x2b0 fs/open.c:1197 kernel_read_file_from_path_initns+0x181/0x240 fs/kernel_read_file.c:163 fw_get_filesystem_firmware drivers/base/firmware_loader/main.c:534 [inline] _request_firmware+0xcac/0x16d0 drivers/base/firmware_loader/main.c:826 request_firmware_work_func+0x126/0x270 drivers/base/firmware_loader/main.c:1095 process_one_work+0x6dc/0xbd0 kernel/workqueue.c:2301 worker_thread+0xaea/0x1510 kernel/workqueue.c:2447 kthread+0x34b/0x3d0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 The buggy address belongs to the object at ffff8881090f5aa0 which belongs to the cache dentry of size 208 The buggy address is located 0 bytes inside of 208-byte region [ffff8881090f5aa0, ffff8881090f5b70) The buggy address belongs to the page: page:ffffea0004243d40 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1090f5 flags: 0x4000000000000200(slab) raw: 4000000000000200 0000000000000000 0000000100000001 ffff888100193380 raw: 0000000000000000 00000000000f000f 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Reclaimable, gfp_mask 0x12cd0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_RECLAIMABLE), pid 1, ts 2577019619, free_ts 0 set_page_owner include/linux/page_owner.h:35 [inline] post_alloc_hook mm/page_alloc.c:2456 [inline] prep_new_page+0x166/0x180 mm/page_alloc.c:2462 get_page_from_freelist+0x2d8c/0x2f30 mm/page_alloc.c:4254 __alloc_pages_nodemask+0x435/0xaf0 mm/page_alloc.c:5348 allocate_slab mm/slub.c:1808 [inline] new_slab+0x80/0x400 mm/slub.c:1869 new_slab_objects mm/slub.c:2627 [inline] ___slab_alloc+0x302/0x4b0 mm/slub.c:2791 __slab_alloc+0x63/0xa0 mm/slub.c:2831 slab_alloc_node mm/slub.c:2913 [inline] slab_alloc mm/slub.c:2955 [inline] kmem_cache_alloc+0x1b9/0x2e0 mm/slub.c:2960 __d_alloc+0x2d/0x6c0 fs/dcache.c:1714 d_alloc fs/dcache.c:1793 [inline] d_alloc_parallel+0xec/0x1370 fs/dcache.c:2547 __lookup_slow+0x154/0x400 fs/namei.c:1625 lookup_one_len+0x180/0x2c0 fs/namei.c:2656 start_creating+0x161/0x2f0 fs/debugfs/inode.c:350 __debugfs_create_file+0x75/0x4c0 fs/debugfs/inode.c:395 debugfs_create_file+0x4a/0x60 fs/debugfs/inode.c:457 debugfs_create_ul lib/fault-inject.c:174 [inline] fault_create_debugfs_attr+0xaa/0x140 lib/fault-inject.c:213 fail_usercopy_debugfs+0x21/0x2d lib/fault-inject-usercopy.c:23 page_owner free stack trace missing Memory state around the buggy address: ffff8881090f5980: fc fc 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8881090f5a00: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc >ffff8881090f5a80: fc fc fc fc fa fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881090f5b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc ffff8881090f5b80: fc fc fc fc fc fc 00 00 00 00 00 00 00 00 00 00 ================================================================== ------------[ cut here ]------------ WARNING: CPU: 0 PID: 290 at fs/dcache.c:766 fast_dput+0x256/0x2a0 fs/dcache.c:766 Modules linked in: CPU: 0 PID: 290 Comm: syz-executor Tainted: G B W 5.10.226-syzkaller-00709-ge5e5644ea27f #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:fast_dput+0x256/0x2a0 fs/dcache.c:766 Code: f1 ff e9 d4 fe ff ff 44 89 e9 80 e1 07 80 c1 03 38 c1 0f 8c f7 fe ff ff 4c 89 ef e8 44 bb f1 ff e9 ea fe ff ff e8 da 20 b4 ff <0f> 0b e9 c0 fe ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 2a ff ff RSP: 0018:ffffc90000b87cd8 EFLAGS: 00010293 RAX: ffffffff81b68c16 RBX: ffff8881090f5afc RCX: ffff88811bd462c0 RDX: 0000000000000000 RSI: 00000000ffffff80 RDI: 0000000000000001 RBP: ffffc90000b87d10 R08: ffffffff81b68b6b R09: 0000000000000003 R10: fffff52000170f8c R11: dffffc0000000001 R12: 00000000ffffff80 R13: ffff8881090f5aa0 R14: ffff8881090f5af8 R15: dffffc0000000000 FS: 0000555581103500(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c2e6899 CR3: 0000000120220000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: dput+0x21/0x80 fs/dcache.c:870 incfs_free_mount_info+0x60/0x210 fs/incfs/data_mgmt.c:166 incfs_kill_sb+0x1c2/0x220 fs/incfs/vfs.c:1979 deactivate_locked_super+0xad/0x110 fs/super.c:335 deactivate_super+0xbe/0xf0 fs/super.c:366 cleanup_mnt+0x45c/0x510 fs/namespace.c:1118 __cleanup_mnt+0x19/0x20 fs/namespace.c:1125 task_work_run+0x129/0x190 kernel/task_work.c:189 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop+0xbf/0xd0 kernel/entry/common.c:172 exit_to_user_mode_prepare kernel/entry/common.c:199 [inline] syscall_exit_to_user_mode+0xa2/0x1a0 kernel/entry/common.c:274 do_syscall_64+0x40/0x70 arch/x86/entry/common.c:56 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f33a13cf327 Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8 RSP: 002b:00007fff52803668 EFLAGS: 00000206 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f33a1440134 RCX: 00007f33a13cf327 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fff52803720 RBP: 00007fff52803720 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000206 R12: 00007fff528047a0 R13: 00007f33a1440134 R14: 00000000000072dd R15: 00007fff528047e0 ---[ end trace 87995346d345d10b ]---