================================================================== BUG: KASAN: slab-use-after-free in handle_mm_fault+0x14f0/0x19a0 mm/memory.c:5842 Read of size 8 at addr ffff88807d61a4f8 by task syz.4.23/5258 CPU: 1 UID: 0 PID: 5258 Comm: syz.4.23 Not tainted 6.10.0-rc7-next-20240712-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 handle_mm_fault+0x14f0/0x19a0 mm/memory.c:5842 do_user_addr_fault arch/x86/mm/fault.c:1389 [inline] handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x2b9/0x8c0 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0010:rep_movs_alternative+0x33/0x70 arch/x86/lib/copy_user_64.S:58 Code: 40 83 f9 08 73 21 85 c9 74 0f 8a 06 88 07 48 ff c7 48 ff c6 48 ff c9 75 f1 c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 48 8b 06 <48> 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 df 83 f9 08 73 e8 eb RSP: 0018:ffffc900045e7bb0 EFLAGS: 00050246 RAX: 0000000000000000 RBX: 0000000020026728 RCX: 0000000000000008 RDX: 0000000000000000 RSI: ffffc900045e7c20 RDI: 0000000020026720 RBP: ffffc900045e7c90 R08: ffffc900045e7c27 R09: 1ffff920008bcf84 R10: dffffc0000000000 R11: fffff520008bcf85 R12: 0000000000000008 R13: 0000000000018ff0 R14: 0000000020026720 R15: ffffc900045e7c20 copy_user_generic arch/x86/include/asm/uaccess_64.h:110 [inline] raw_copy_to_user arch/x86/include/asm/uaccess_64.h:131 [inline] _inline_copy_to_user include/linux/uaccess.h:181 [inline] _copy_to_user+0x86/0xb0 lib/usercopy.c:26 copy_to_user include/linux/uaccess.h:209 [inline] msr_read+0x187/0x260 arch/x86/kernel/msr.c:69 vfs_read+0x204/0xbc0 fs/read_write.c:474 ksys_read+0x1a0/0x2c0 fs/read_write.c:619 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa954b75bd9 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:00007fa955919048 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007fa954d03f60 RCX: 00007fa954b75bd9 RDX: 0000000000018ff8 RSI: 0000000020019680 RDI: 0000000000000003 RBP: 00007fa954be4e60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007fa954d03f60 R15: 00007ffd8c40c798 Allocated by task 5259: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:312 [inline] __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3988 [inline] slab_alloc_node mm/slub.c:4037 [inline] kmem_cache_alloc_noprof+0x135/0x2a0 mm/slub.c:4044 vm_area_dup+0x27/0x290 kernel/fork.c:487 __split_vma+0x1a9/0xc30 mm/mmap.c:2465 split_vma mm/mmap.c:2537 [inline] vma_modify+0x268/0x350 mm/mmap.c:2578 vma_modify_flags_uffd include/linux/mm.h:3352 [inline] userfaultfd_register fs/userfaultfd.c:1458 [inline] userfaultfd_ioctl+0x5603/0x70a0 fs/userfaultfd.c:2124 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 24: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579 poison_slab_object+0xe0/0x150 mm/kasan/common.c:240 __kasan_slab_free+0x37/0x60 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2252 [inline] slab_free mm/slub.c:4473 [inline] kmem_cache_free+0x145/0x350 mm/slub.c:4548 rcu_do_batch kernel/rcu/tree.c:2569 [inline] rcu_core+0xafd/0x1830 kernel/rcu/tree.c:2843 handle_softirqs+0x2c4/0x970 kernel/softirq.c:554 run_ksoftirqd+0xca/0x130 kernel/softirq.c:928 smpboot_thread_fn+0x544/0xa30 kernel/smpboot.c:164 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:144 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Last potentially related work creation: kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47 __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:541 __call_rcu_common kernel/rcu/tree.c:3106 [inline] call_rcu+0x167/0xa70 kernel/rcu/tree.c:3210 vma_complete+0x98a/0xb60 mm/mmap.c:609 vma_merge+0x1d9b/0x2690 mm/mmap.c:1079 vma_modify+0xb8/0x350 mm/mmap.c:2565 vma_modify_flags_uffd include/linux/mm.h:3352 [inline] userfaultfd_release+0x413/0x900 fs/userfaultfd.c:907 __fput+0x24a/0x8a0 fs/file_table.c:422 __do_sys_close fs/open.c:1566 [inline] __se_sys_close fs/open.c:1551 [inline] __x64_sys_close+0x7f/0x110 fs/open.c:1551 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88807d61a4d8 which belongs to the cache vm_area_struct of size 184 The buggy address is located 32 bytes inside of freed 184-byte region [ffff88807d61a4d8, ffff88807d61a590) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7d61a memcg:ffff88802cdd8101 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: 0xfdffffff(slab) raw: 00fff00000000000 ffff888015eefb40 ffffea00008f8800 dead000000000004 raw: 0000000000000000 0000000000100010 00000001fdffffff ffff88802cdd8101 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 4770, tgid 4770 (dhcpcd), ts 31303547500, free_ts 30557105069 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1493 prep_new_page mm/page_alloc.c:1501 [inline] get_page_from_freelist+0x2ccb/0x2d80 mm/page_alloc.c:3474 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4732 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline] alloc_pages_node_noprof include/linux/gfp.h:296 [inline] alloc_slab_page+0x5f/0x120 mm/slub.c:2321 allocate_slab+0x5a/0x2f0 mm/slub.c:2484 new_slab mm/slub.c:2537 [inline] ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3723 __slab_alloc+0x58/0xa0 mm/slub.c:3813 __slab_alloc_node mm/slub.c:3866 [inline] slab_alloc_node mm/slub.c:4025 [inline] kmem_cache_alloc_noprof+0x1c1/0x2a0 mm/slub.c:4044 vm_area_dup+0x27/0x290 kernel/fork.c:487 dup_mmap kernel/fork.c:696 [inline] dup_mm kernel/fork.c:1674 [inline] copy_mm+0xc7b/0x1f30 kernel/fork.c:1723 copy_process+0x186b/0x3d90 kernel/fork.c:2376 kernel_clone+0x226/0x8f0 kernel/fork.c:2788 __do_sys_clone kernel/fork.c:2931 [inline] __se_sys_clone kernel/fork.c:2915 [inline] __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2915 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 4916 tgid 4916 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1094 [inline] free_unref_page+0xd22/0xea0 mm/page_alloc.c:2644 discard_slab mm/slub.c:2583 [inline] __put_partials+0xeb/0x130 mm/slub.c:3051 put_cpu_partial+0x17c/0x250 mm/slub.c:3126 __slab_free+0x2ea/0x3d0 mm/slub.c:4343 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9e/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:322 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3988 [inline] slab_alloc_node mm/slub.c:4037 [inline] kmem_cache_alloc_noprof+0x135/0x2a0 mm/slub.c:4044 vm_area_alloc+0x24/0x1d0 kernel/fork.c:472 mmap_region+0xc3d/0x2090 mm/mmap.c:2944 do_mmap+0x8f9/0x1010 mm/mmap.c:1468 vm_mmap_pgoff+0x1dd/0x3d0 mm/util.c:588 ksys_mmap_pgoff+0x4f1/0x720 mm/mmap.c:1514 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88807d61a380: 00 00 00 00 fc fc fc fc fc fc fc fc 00 00 00 00 ffff88807d61a400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88807d61a480: 00 00 00 fc fc fc fc fc fc fc fc fa fb fb fb fb ^ ffff88807d61a500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807d61a580: fb fb fc fc fc fc fc fc fc fc fa fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess): 0: 40 83 f9 08 rex cmp $0x8,%ecx 4: 73 21 jae 0x27 6: 85 c9 test %ecx,%ecx 8: 74 0f je 0x19 a: 8a 06 mov (%rsi),%al c: 88 07 mov %al,(%rdi) e: 48 ff c7 inc %rdi 11: 48 ff c6 inc %rsi 14: 48 ff c9 dec %rcx 17: 75 f1 jne 0xa 19: c3 ret 1a: cc int3 1b: cc int3 1c: cc int3 1d: cc int3 1e: 66 0f 1f 84 00 00 00 nopw 0x0(%rax,%rax,1) 25: 00 00 27: 48 8b 06 mov (%rsi),%rax * 2a: 48 89 07 mov %rax,(%rdi) <-- trapping instruction 2d: 48 83 c6 08 add $0x8,%rsi 31: 48 83 c7 08 add $0x8,%rdi 35: 83 e9 08 sub $0x8,%ecx 38: 74 df je 0x19 3a: 83 f9 08 cmp $0x8,%ecx 3d: 73 e8 jae 0x27 3f: eb .byte 0xeb