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Content-Language: en-US Cc: akpm@linux-foundation.org, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mingo@redhat.com, syzkaller-bugs@googlegroups.com, tglx@linutronix.de, x86@kernel.org In-Reply-To: <67548279.050a0220.a30f1.015b.GAE@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2024/12/8 01:14, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: af2ea8ab7a54 Add linux-next specific files for 20241205 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=13c4e8df980000 > kernel config: https://syzkaller.appspot.com/x/.config?x=76f158395f6f15fd > dashboard link: https://syzkaller.appspot.com/bug?extid=1c58afed1cfd2f57efee > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=133850f8580000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17be9330580000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/8af0861258fa/disk-af2ea8ab.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/ffb38cf7a344/vmlinux-af2ea8ab.xz > kernel image: https://storage.googleapis.com/syzbot-assets/6fbd2e50358a/bzImage-af2ea8ab.xz > > The issue was bisected to: > > commit 5b29c4156f5801fced2ec504b44ab98f60c480bf > Author: Qi Zheng > Date: Wed Dec 4 11:09:51 2024 +0000 > > x86: select ARCH_SUPPORTS_PT_RECLAIM if X86_64 > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16d344df980000 > final oops: https://syzkaller.appspot.com/x/report.txt?x=15d344df980000 > console output: https://syzkaller.appspot.com/x/log.txt?x=11d344df980000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+1c58afed1cfd2f57efee@syzkaller.appspotmail.com > Fixes: 5b29c4156f58 ("x86: select ARCH_SUPPORTS_PT_RECLAIM if X86_64") > > ================================================================== > BUG: KASAN: slab-use-after-free in __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089 > Read of size 8 at addr ffff888034718978 by task syz-executor352/6070 > > CPU: 0 UID: 0 PID: 6070 Comm: syz-executor352 Not tainted 6.13.0-rc1-next-20241205-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 > 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:378 [inline] > print_report+0x169/0x550 mm/kasan/report.c:489 > kasan_report+0x143/0x180 mm/kasan/report.c:602 > __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089 > lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 > __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] > _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 > spin_lock include/linux/spinlock.h:351 [inline] > move_pages_pte+0x8aa/0x3400 mm/userfaultfd.c:1248 > move_pages+0xe75/0x16a0 mm/userfaultfd.c:1754 > userfaultfd_move fs/userfaultfd.c:1899 [inline] > userfaultfd_ioctl+0x5221/0x6840 fs/userfaultfd.c:2022 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:906 [inline] > __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 > 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: 0033:0x7fed8de85af9 > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 18 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007fed8de40238 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 00007fed8df10328 RCX: 00007fed8de85af9 > RDX: 0000000020000080 RSI: 00000000c028aa05 RDI: 0000000000000003 > RBP: 00007fed8df10320 R08: 00007fed8de406c0 R09: 00007fed8de406c0 > R10: 00007fed8de406c0 R11: 0000000000000246 R12: 00007fed8dedd334 > R13: 0000000000000010 R14: 00007ffc241241e0 R15: 00007ffc241242c8 > > > Allocated by task 6070: > 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:319 [inline] > __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345 > kasan_slab_alloc include/linux/kasan.h:250 [inline] > slab_post_alloc_hook mm/slub.c:4104 [inline] > slab_alloc_node mm/slub.c:4153 [inline] > kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4160 > ptlock_alloc+0x20/0x70 mm/memory.c:7026 > ptlock_init include/linux/mm.h:2971 [inline] > pagetable_pte_ctor include/linux/mm.h:2998 [inline] > __pte_alloc_one_noprof include/asm-generic/pgalloc.h:73 [inline] > pte_alloc_one+0xd3/0x510 arch/x86/mm/pgtable.c:41 > __do_huge_pmd_anonymous_page mm/huge_memory.c:1229 [inline] > do_huge_pmd_anonymous_page+0x2fb/0xb30 mm/huge_memory.c:1374 > create_huge_pmd mm/memory.c:5737 [inline] > __handle_mm_fault mm/memory.c:5986 [inline] > handle_mm_fault+0x15a7/0x1bb0 mm/memory.c:6183 > do_user_addr_fault arch/x86/mm/fault.c:1338 [inline] > handle_page_fault arch/x86/mm/fault.c:1481 [inline] > exc_page_fault+0x459/0x8b0 arch/x86/mm/fault.c:1539 > asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 > > Freed by task 6071: > 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:576 > poison_slab_object mm/kasan/common.c:247 [inline] > __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264 > kasan_slab_free include/linux/kasan.h:233 [inline] > slab_free_hook mm/slub.c:2338 [inline] > slab_free mm/slub.c:4598 [inline] > kmem_cache_free+0x195/0x410 mm/slub.c:4700 > pagetable_pte_dtor include/linux/mm.h:3009 [inline] OK, so the problem is that ptdesc->ptl is not freed via RCU: ___pte_free_tlb --> pagetable_pte_dtor --> ptlock_free --> kmem_cache_free (free immediately!) paravirt_tlb_remove_table --> free PTE page via RCU In retract_page_tables(), it calls pte_free_defer() to free ptdesc->ptl and PTE page via RCU, so there is no problem. To fix it, will also free ptdesc->ptl in ptlock_free() via RCU. > ___pte_free_tlb+0x2b/0x140 arch/x86/mm/pgtable.c:63 > __pte_free_tlb arch/x86/include/asm/pgalloc.h:61 [inline] > free_pte+0x142/0x190 mm/pt_reclaim.c:31 > zap_pte_range mm/memory.c:1780 [inline] > zap_pmd_range mm/memory.c:1822 [inline] > zap_pud_range mm/memory.c:1851 [inline] > zap_p4d_range mm/memory.c:1872 [inline] > unmap_page_range+0x4062/0x48d0 mm/memory.c:1893 > zap_page_range_single+0x45c/0x630 mm/memory.c:2018 > madvise_dontneed_single_vma mm/madvise.c:859 [inline] > madvise_dontneed_free mm/madvise.c:940 [inline] > madvise_vma_behavior mm/madvise.c:1270 [inline] > madvise_walk_vmas mm/madvise.c:1502 [inline] > do_madvise+0x2774/0x4d90 mm/madvise.c:1689 > __do_sys_madvise mm/madvise.c:1705 [inline] > __se_sys_madvise mm/madvise.c:1703 [inline] > __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:1703 > 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 ffff888034718960 > which belongs to the cache page->ptl of size 64 > The buggy address is located 24 bytes inside of > freed 64-byte region [ffff888034718960, ffff8880347189a0) > > The buggy address belongs to the physical page: > page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x34718 > flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) > page_type: f5(slab) > raw: 00fff00000000000 ffff88801ac4f780 dead000000000122 0000000000000000 > raw: 0000000000000000 00000000802a002a 00000000f5000000 0000000000000000 > 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 5823, tgid 5823 (syz-executor352), ts 65548803787, free_ts 65433386693 > set_page_owner include/linux/page_owner.h:32 [inline] > post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1549 > prep_new_page mm/page_alloc.c:1557 [inline] > get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3475 > __alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4752 > alloc_pages_mpol+0x30e/0x550 mm/mempolicy.c:2270 > alloc_slab_page mm/slub.c:2408 [inline] > allocate_slab+0x8f/0x3a0 mm/slub.c:2574 > new_slab mm/slub.c:2627 [inline] > ___slab_alloc+0xc27/0x14a0 mm/slub.c:3815 > __slab_alloc+0x58/0xa0 mm/slub.c:3905 > __slab_alloc_node mm/slub.c:3980 [inline] > slab_alloc_node mm/slub.c:4141 [inline] > kmem_cache_alloc_noprof+0x268/0x380 mm/slub.c:4160 > ptlock_alloc mm/memory.c:7026 [inline] > ptlock_init include/linux/mm.h:2971 [inline] > pmd_ptlock_init include/linux/mm.h:3078 [inline] > pagetable_pmd_ctor include/linux/mm.h:3116 [inline] > pmd_alloc_one_noprof include/asm-generic/pgalloc.h:141 [inline] > __pmd_alloc+0x10b/0x670 mm/memory.c:6436 > pmd_alloc include/linux/mm.h:2862 [inline] > copy_pmd_range+0x7352/0x77a0 mm/memory.c:1241 > copy_pud_range mm/memory.c:1298 [inline] > copy_p4d_range mm/memory.c:1322 [inline] > copy_page_range+0x99f/0xe90 mm/memory.c:1420 > dup_mmap kernel/fork.c:751 [inline] > dup_mm kernel/fork.c:1693 [inline] > copy_mm+0x12d2/0x2060 kernel/fork.c:1742 > copy_process+0x1845/0x3d80 kernel/fork.c:2393 > kernel_clone+0x226/0x8e0 kernel/fork.c:2805 > __do_sys_clone kernel/fork.c:2948 [inline] > __se_sys_clone kernel/fork.c:2932 [inline] > __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2932 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 > page last free pid 6052 tgid 6051 stack trace: > reset_page_owner include/linux/page_owner.h:25 [inline] > free_pages_prepare mm/page_alloc.c:1127 [inline] > free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2658 > __folio_put+0x2b3/0x360 mm/swap.c:112 > __tlb_remove_table arch/x86/include/asm/tlb.h:34 [inline] > __tlb_remove_table_free mm/mmu_gather.c:227 [inline] > tlb_remove_table_rcu+0x76/0xf0 mm/mmu_gather.c:282 > rcu_do_batch kernel/rcu/tree.c:2567 [inline] > rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2823 > handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561 > __do_softirq kernel/softirq.c:595 [inline] > invoke_softirq kernel/softirq.c:435 [inline] > __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662 > irq_exit_rcu+0x9/0x30 kernel/softirq.c:678 > instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] > sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049 > asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 > > Memory state around the buggy address: > ffff888034718800: 00 00 00 00 fc fc fc fc 00 00 00 00 00 00 00 00 > ffff888034718880: fc fc fc fc 00 00 00 00 00 00 00 00 fc fc fc fc >> ffff888034718900: 00 00 00 00 00 00 00 00 fc fc fc fc fa fb fb fb > ^ > ffff888034718980: fb fb fb fb fc fc fc fc fa fb fb fb fb fb fb fb > ffff888034718a00: fc fc fc fc 00 00 00 00 00 00 00 00 fc fc fc fc > ================================================================== > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@googlegroups.com. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > For information about bisection process see: https://goo.gl/tpsmEJ#bisection > > If the report is already addressed, let syzbot know by replying with: > #syz fix: exact-commit-title > > If you want syzbot to run the reproducer, reply with: > #syz test: git://repo/address.git branch-or-commit-hash > If you attach or paste a git patch, syzbot will apply it before testing. > > If you want to overwrite report's subsystems, reply with: > #syz set subsystems: new-subsystem > (See the list of subsystem names on the web dashboard) > > If the report is a duplicate of another one, reply with: > #syz dup: exact-subject-of-another-report > > If you want to undo deduplication, reply with: > #syz undup