================================================================== BUG: KASAN: slab-use-after-free in ovl_dentry_remote fs/overlayfs/util.c:162 [inline] BUG: KASAN: slab-use-after-free in ovl_dentry_update_reval+0xd2/0xf0 fs/overlayfs/util.c:167 Read of size 4 at addr ffff888029a2b780 by task syz.0.4296/16785 CPU: 0 PID: 16785 Comm: syz.0.4296 Not tainted 6.10.0-rc6-syzkaller-00041-g9903efbddba0 #0 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:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc3/0x620 mm/kasan/report.c:488 kasan_report+0xd9/0x110 mm/kasan/report.c:601 ovl_dentry_remote fs/overlayfs/util.c:162 [inline] ovl_dentry_update_reval+0xd2/0xf0 fs/overlayfs/util.c:167 ovl_link_up fs/overlayfs/copy_up.c:610 [inline] ovl_copy_up_one+0x2105/0x3490 fs/overlayfs/copy_up.c:1170 ovl_copy_up_flags+0x18d/0x200 fs/overlayfs/copy_up.c:1223 ovl_rename+0x39e/0x18c0 fs/overlayfs/dir.c:1136 vfs_rename+0xf84/0x20a0 fs/namei.c:4893 do_renameat2+0xc54/0xdc0 fs/namei.c:5050 __do_sys_renameat2 fs/namei.c:5084 [inline] __se_sys_renameat2 fs/namei.c:5081 [inline] __ia32_sys_renameat2+0xeb/0x130 fs/namei.c:5081 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf745b579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f5d7357c EFLAGS: 00000292 ORIG_RAX: 0000000000000161 RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 0000000020000080 RDX: 0000000000000008 RSI: 0000000020000580 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 16785: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:312 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:338 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3940 [inline] slab_alloc_node mm/slub.c:4002 [inline] kmem_cache_alloc_lru_noprof+0x121/0x2f0 mm/slub.c:4021 __d_alloc+0x35/0x8c0 fs/dcache.c:1624 d_alloc+0x4a/0x1e0 fs/dcache.c:1704 d_alloc_parallel+0xe9/0x12b0 fs/dcache.c:2462 __lookup_slow+0x194/0x460 fs/namei.c:1677 lookup_one+0x185/0x1c0 fs/namei.c:2794 ovl_lookup_upper fs/overlayfs/overlayfs.h:404 [inline] ovl_link_up fs/overlayfs/copy_up.c:599 [inline] ovl_copy_up_one+0x105a/0x3490 fs/overlayfs/copy_up.c:1170 ovl_copy_up_flags+0x18d/0x200 fs/overlayfs/copy_up.c:1223 ovl_rename+0x39e/0x18c0 fs/overlayfs/dir.c:1136 vfs_rename+0xf84/0x20a0 fs/namei.c:4893 do_renameat2+0xc54/0xdc0 fs/namei.c:5050 __do_sys_renameat2 fs/namei.c:5084 [inline] __se_sys_renameat2 fs/namei.c:5081 [inline] __ia32_sys_renameat2+0xeb/0x130 fs/namei.c:5081 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e Freed by task 111: 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:579 poison_slab_object+0xf7/0x160 mm/kasan/common.c:240 __kasan_slab_free+0x32/0x50 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2196 [inline] slab_free mm/slub.c:4438 [inline] kmem_cache_free+0x12f/0x3a0 mm/slub.c:4513 rcu_do_batch kernel/rcu/tree.c:2535 [inline] rcu_core+0x828/0x16b0 kernel/rcu/tree.c:2809 handle_softirqs+0x216/0x8f0 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu kernel/softirq.c:637 [inline] irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 Last potentially related work creation: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 __kasan_record_aux_stack+0xba/0xd0 mm/kasan/generic.c:541 __call_rcu_common.constprop.0+0x9a/0x790 kernel/rcu/tree.c:3072 dentry_free+0xc2/0x160 fs/dcache.c:376 __dentry_kill+0x498/0x600 fs/dcache.c:622 shrink_kill fs/dcache.c:1048 [inline] shrink_dentry_list+0x140/0x5d0 fs/dcache.c:1075 prune_dcache_sb+0xeb/0x150 fs/dcache.c:1156 super_cache_scan+0x32a/0x550 fs/super.c:221 do_shrink_slab+0x44f/0x11c0 mm/shrinker.c:435 shrink_slab_memcg mm/shrinker.c:548 [inline] shrink_slab+0xa87/0x1310 mm/shrinker.c:626 shrink_one+0x493/0x7c0 mm/vmscan.c:4790 shrink_many mm/vmscan.c:4851 [inline] lru_gen_shrink_node+0x89f/0x1750 mm/vmscan.c:4951 shrink_node mm/vmscan.c:5910 [inline] kswapd_shrink_node mm/vmscan.c:6720 [inline] balance_pgdat+0x1105/0x1970 mm/vmscan.c:6911 kswapd+0x5ea/0xbf0 mm/vmscan.c:7180 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 The buggy address belongs to the object at ffff888029a2b780 which belongs to the cache dentry of size 312 The buggy address is located 0 bytes inside of freed 312-byte region [ffff888029a2b780, ffff888029a2b8b8) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x29a2a head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 memcg:ffff88801bc54a01 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffefff(slab) raw: 00fff00000000040 ffff8880166a3400 ffffea0000a68180 dead000000000002 raw: 0000000000000000 0000000080150015 00000001ffffefff ffff88801bc54a01 head: 00fff00000000040 ffff8880166a3400 ffffea0000a68180 dead000000000002 head: 0000000000000000 0000000080150015 00000001ffffefff ffff88801bc54a01 head: 00fff00000000001 ffffea0000a68a81 ffffffffffffffff 0000000000000000 head: 0000000000000002 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Reclaimable, gfp_mask 0xd20d0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_RECLAIMABLE), pid 4704, tgid 4704 (udevd), ts 31781364549, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1473 prep_new_page mm/page_alloc.c:1481 [inline] get_page_from_freelist+0x1353/0x2e50 mm/page_alloc.c:3425 __alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4683 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline] alloc_pages_node_noprof include/linux/gfp.h:296 [inline] alloc_slab_page+0x56/0x110 mm/slub.c:2265 allocate_slab mm/slub.c:2428 [inline] new_slab+0x84/0x260 mm/slub.c:2481 ___slab_alloc+0xdac/0x1870 mm/slub.c:3667 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3757 __slab_alloc_node mm/slub.c:3810 [inline] slab_alloc_node mm/slub.c:3990 [inline] kmem_cache_alloc_lru_noprof+0x2a7/0x2f0 mm/slub.c:4021 __d_alloc+0x35/0x8c0 fs/dcache.c:1624 d_alloc+0x4a/0x1e0 fs/dcache.c:1704 d_alloc_parallel+0xe9/0x12b0 fs/dcache.c:2462 __lookup_slow+0x194/0x460 fs/namei.c:1677 lookup_slow fs/namei.c:1709 [inline] walk_component+0x350/0x5b0 fs/namei.c:2004 lookup_last fs/namei.c:2469 [inline] path_lookupat+0x17f/0x770 fs/namei.c:2493 filename_lookup+0x1e5/0x5b0 fs/namei.c:2522 vfs_statx+0x13e/0x550 fs/stat.c:244 page_owner free stack trace missing Memory state around the buggy address: ffff888029a2b680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888029a2b700: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc >ffff888029a2b780: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888029a2b800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888029a2b880: fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc fa ================================================================== ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi