================================================================== BUG: KASAN: use-after-free in mas_safe_min lib/maple_tree.c:721 [inline] BUG: KASAN: use-after-free in mas_next_nentry+0x9e4/0xab0 lib/maple_tree.c:4662 Read of size 8 at addr ffff888079947e20 by task syz-executor.1/26483 CPU: 0 PID: 26483 Comm: syz-executor.1 Not tainted 6.1.0-rc1-syzkaller-00134-ge35184f32151 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:284 [inline] print_report+0x15e/0x45d mm/kasan/report.c:395 kasan_report+0xbb/0x1f0 mm/kasan/report.c:495 mas_safe_min lib/maple_tree.c:721 [inline] mas_next_nentry+0x9e4/0xab0 lib/maple_tree.c:4662 mas_next_entry lib/maple_tree.c:4757 [inline] mas_next+0x1fb/0xc90 lib/maple_tree.c:5868 userfaultfd_unregister fs/userfaultfd.c:1657 [inline] userfaultfd_ioctl+0x33c3/0x4200 fs/userfaultfd.c:2005 compat_ptr_ioctl+0x67/0x90 fs/ioctl.c:906 __do_compat_sys_ioctl+0x1c7/0x290 fs/ioctl.c:968 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 RIP: 0023:0xf7f5d549 Code: 03 74 c0 01 10 05 03 74 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 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:00000000f7f585cc EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000008010aa01 RDX: 00000000200000c0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 26483: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:45 kasan_set_track+0x21/0x30 mm/kasan/common.c:52 __kasan_slab_alloc+0x7e/0x80 mm/kasan/common.c:325 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slab.h:737 [inline] kmem_cache_alloc_bulk+0x3e9/0x830 mm/slub.c:3854 mt_alloc_bulk lib/maple_tree.c:157 [inline] mas_alloc_nodes+0x309/0x810 lib/maple_tree.c:1256 mas_node_count_gfp lib/maple_tree.c:1316 [inline] mas_preallocate+0x1b7/0x360 lib/maple_tree.c:5719 __vma_adjust+0x181/0x1a70 mm/mmap.c:715 vma_adjust include/linux/mm.h:2663 [inline] __split_vma+0x295/0x5c0 mm/mmap.c:2239 split_vma+0x9f/0xe0 mm/mmap.c:2272 userfaultfd_register fs/userfaultfd.c:1454 [inline] userfaultfd_ioctl+0x3a8c/0x4200 fs/userfaultfd.c:2002 compat_ptr_ioctl+0x67/0x90 fs/ioctl.c:906 __do_compat_sys_ioctl+0x1c7/0x290 fs/ioctl.c:968 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 Freed by task 26483: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:45 kasan_set_track+0x21/0x30 mm/kasan/common.c:52 kasan_save_free_info+0x2a/0x40 mm/kasan/generic.c:511 ____kasan_slab_free mm/kasan/common.c:236 [inline] ____kasan_slab_free+0x160/0x1c0 mm/kasan/common.c:200 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1724 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1750 slab_free mm/slub.c:3661 [inline] kmem_cache_free_bulk.part.0+0x205/0x780 mm/slub.c:3779 mt_free_bulk lib/maple_tree.c:163 [inline] mas_destroy+0x394/0x5c0 lib/maple_tree.c:5769 mas_store_prealloc+0xec/0x150 lib/maple_tree.c:5704 __vma_adjust+0x765/0x1a70 mm/mmap.c:810 vma_adjust include/linux/mm.h:2663 [inline] __split_vma+0x295/0x5c0 mm/mmap.c:2239 split_vma+0x9f/0xe0 mm/mmap.c:2272 userfaultfd_unregister fs/userfaultfd.c:1641 [inline] userfaultfd_ioctl+0x3819/0x4200 fs/userfaultfd.c:2005 compat_ptr_ioctl+0x67/0x90 fs/ioctl.c:906 __do_compat_sys_ioctl+0x1c7/0x290 fs/ioctl.c:968 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 The buggy address belongs to the object at ffff888079947e00 which belongs to the cache maple_node of size 256 The buggy address is located 32 bytes inside of 256-byte region [ffff888079947e00, ffff888079947f00) The buggy address belongs to the physical page: page:ffffea0001e65180 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x79946 head:ffffea0001e65180 order:1 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000001 ffff88801184fdc0 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0x52800(GFP_NOWAIT|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 3182, tgid 3182 (dhcpcd), ts 22001679718, free_ts 21136251388 prep_new_page mm/page_alloc.c:2538 [inline] get_page_from_freelist+0x10b5/0x2d50 mm/page_alloc.c:4287 __alloc_pages+0x1c7/0x5a0 mm/page_alloc.c:5554 alloc_pages+0x1a6/0x270 mm/mempolicy.c:2280 alloc_slab_page mm/slub.c:1794 [inline] allocate_slab+0x213/0x300 mm/slub.c:1939 new_slab mm/slub.c:1992 [inline] ___slab_alloc+0xa91/0x1400 mm/slub.c:3180 kmem_cache_alloc_bulk+0x28b/0x830 mm/slub.c:3830 mt_alloc_bulk lib/maple_tree.c:157 [inline] mas_alloc_nodes+0x309/0x810 lib/maple_tree.c:1256 mas_node_count_gfp+0x106/0x140 lib/maple_tree.c:1316 mas_node_count lib/maple_tree.c:1330 [inline] mas_expected_entries+0x113/0x200 lib/maple_tree.c:5822 dup_mmap+0x4ca/0x10b0 kernel/fork.c:613 dup_mm+0x91/0x370 kernel/fork.c:1526 copy_mm kernel/fork.c:1575 [inline] copy_process+0x3bc6/0x7190 kernel/fork.c:2253 kernel_clone+0xe7/0x980 kernel/fork.c:2671 __do_sys_clone+0xba/0x100 kernel/fork.c:2812 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1458 [inline] free_pcp_prepare+0x65c/0xd90 mm/page_alloc.c:1508 free_unref_page_prepare mm/page_alloc.c:3386 [inline] free_unref_page+0x19/0x4d0 mm/page_alloc.c:3482 __unfreeze_partials+0x17c/0x1a0 mm/slub.c:2586 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x62/0x80 mm/kasan/common.c:302 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slab.h:737 [inline] slab_alloc_node mm/slub.c:3398 [inline] slab_alloc mm/slub.c:3406 [inline] __kmem_cache_alloc_lru mm/slub.c:3413 [inline] kmem_cache_alloc+0x2ac/0x3c0 mm/slub.c:3422 getname_flags.part.0+0x50/0x4f0 fs/namei.c:139 getname_flags+0x9a/0xe0 include/linux/audit.h:320 user_path_at_empty+0x2b/0x60 fs/namei.c:2875 do_readlinkat+0xcd/0x2f0 fs/stat.c:468 __do_sys_readlink fs/stat.c:501 [inline] __se_sys_readlink fs/stat.c:498 [inline] __x64_sys_readlink+0x74/0xb0 fs/stat.c:498 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Memory state around the buggy address: ffff888079947d00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888079947d80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888079947e00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888079947e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888079947f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== ---------------- Code disassembly (best guess): 0: 03 74 c0 01 add 0x1(%rax,%rax,8),%esi 4: 10 05 03 74 b8 01 adc %al,0x1b87403(%rip) # 0x1b8740d a: 10 06 adc %al,(%rsi) c: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 10: 10 07 adc %al,(%rdi) 12: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi 16: 10 08 adc %cl,(%rax) 18: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1c: 00 00 add %al,(%rax) 1e: 00 00 add %al,(%rax) 20: 00 51 52 add %dl,0x52(%rcx) 23: 55 push %rbp 24: 89 e5 mov %esp,%ebp 26: 0f 34 sysenter 28: cd 80 int $0x80 * 2a: 5d pop %rbp <-- trapping instruction 2b: 5a pop %rdx 2c: 59 pop %rcx 2d: c3 retq 2e: 90 nop 2f: 90 nop 30: 90 nop 31: 90 nop 32: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 39: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi