syzbot

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BUG: KASAN: slab-use-after-free in ocfs2_fault+0xd3/0x400 fs/ocfs2/mmap.c:41
Read of size 8 at addr ffff8880112b8a58 by task syz.2.147/6776

CPU: 1 UID: 0 PID: 6776 Comm: syz.2.147 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 ocfs2_fault+0xd3/0x400 fs/ocfs2/mmap.c:41
 __do_fault+0x135/0x390 mm/memory.c:5152
 do_read_fault mm/memory.c:5573 [inline]
 do_fault mm/memory.c:5707 [inline]
 do_pte_missing mm/memory.c:4234 [inline]
 handle_pte_fault mm/memory.c:6052 [inline]
 __handle_mm_fault mm/memory.c:6195 [inline]
 handle_mm_fault+0x23c6/0x3400 mm/memory.c:6364
 faultin_page mm/gup.c:1144 [inline]
 __get_user_pages+0x16e4/0x2b60 mm/gup.c:1446
 populate_vma_page_range+0x29f/0x3a0 mm/gup.c:1880
 __mm_populate+0x24c/0x380 mm/gup.c:1983
 mm_populate include/linux/mm.h:3367 [inline]
 vm_mmap_pgoff+0x38a/0x4d0 mm/util.c:585
 ksys_mmap_pgoff+0x4e9/0x720 mm/mmap.c:604
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f22ec51eba9
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:00007f22ebb8e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f22ec765fa0 RCX: 00007f22ec51eba9
RDX: 00000000027ffff7 RSI: 0000000000600000 RDI: 0000200000000000
RBP: 00007f22ec5a1e19 R08: 0000000000000004 R09: 0000000000000000
R10: 0000000004012011 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f22ec766038 R14: 00007f22ec765fa0 R15: 00007ffdd27f6b38
 </TASK>

Allocated by task 6776:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:330 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:356
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4191 [inline]
 slab_alloc_node mm/slub.c:4240 [inline]
 kmem_cache_alloc_noprof+0x143/0x310 mm/slub.c:4247
 vm_area_alloc+0x24/0x140 mm/vma_init.c:31
 __mmap_new_vma mm/vma.c:2461 [inline]
 __mmap_region mm/vma.c:2669 [inline]
 mmap_region+0xdd2/0x20a0 mm/vma.c:2739
 do_mmap+0xc23/0x10c0 mm/mmap.c:558
 vm_mmap_pgoff+0x2a9/0x4d0 mm/util.c:580
 ksys_mmap_pgoff+0x4e9/0x720 mm/mmap.c:604
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 20:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:243 [inline]
 __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2422 [inline]
 slab_free_after_rcu_debug+0x129/0x3c0 mm/slub.c:4745
 rcu_do_batch kernel/rcu/tree.c:2605 [inline]
 rcu_core kernel/rcu/tree.c:2861 [inline]
 rcu_cpu_kthread+0xbf3/0x1b50 kernel/rcu/tree.c:2949
 smpboot_thread_fn+0x53f/0xa60 kernel/smpboot.c:160
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:548
 slab_free_hook mm/slub.c:2383 [inline]
 slab_free mm/slub.c:4695 [inline]
 kmem_cache_free+0x3ef/0x510 mm/slub.c:4797
 remove_vma mm/vma.c:468 [inline]
 vms_complete_munmap_vmas+0x626/0x8a0 mm/vma.c:1293
 do_vmi_align_munmap+0x369/0x440 mm/vma.c:1536
 do_vmi_munmap+0x253/0x2e0 mm/vma.c:1584
 __vm_munmap+0x23b/0x3d0 mm/vma.c:3155
 __do_sys_munmap mm/mmap.c:1080 [inline]
 __se_sys_munmap mm/mmap.c:1077 [inline]
 __x64_sys_munmap+0x60/0x70 mm/mmap.c:1077
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8880112b8a00
 which belongs to the cache vm_area_struct of size 256
The buggy address is located 88 bytes inside of
 freed 256-byte region [ffff8880112b8a00, ffff8880112b8b00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x112b8
memcg:ffff88802dbbdf01
anon flags: 0x80000000000000(node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000000 ffff888140409b40 ffffea0000d7b000 dead000000000005
raw: 0000000000000000 00000000800c000c 00000000f5000000 ffff88802dbbdf01
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 5565, tgid 5565 (dhcpcd-run-hook), ts 65402781767, free_ts 56296721729
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x2119/0x21b0 mm/page_alloc.c:3858
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5148
 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:2492 [inline]
 allocate_slab+0x8a/0x370 mm/slub.c:2660
 new_slab mm/slub.c:2714 [inline]
 ___slab_alloc+0x8d1/0xdc0 mm/slub.c:3901
 __slab_alloc mm/slub.c:3992 [inline]
 __slab_alloc_node mm/slub.c:4067 [inline]
 slab_alloc_node mm/slub.c:4228 [inline]
 kmem_cache_alloc_noprof+0xe6/0x310 mm/slub.c:4247
 vm_area_dup+0x2b/0x670 mm/vma_init.c:122
 __split_vma+0x1ad/0x9e0 mm/vma.c:515
 vms_gather_munmap_vmas+0x2ea/0x12f0 mm/vma.c:1359
 __mmap_prepare mm/vma.c:2359 [inline]
 __mmap_region mm/vma.c:2651 [inline]
 mmap_region+0x729/0x20a0 mm/vma.c:2739
 do_mmap+0xc23/0x10c0 mm/mmap.c:558
 vm_mmap_pgoff+0x2a9/0x4d0 mm/util.c:580
 ksys_mmap_pgoff+0x4e9/0x720 mm/mmap.c:604
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 28 tgid 28 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0xb59/0xce0 mm/page_alloc.c:2895
 pagetable_free include/linux/mm.h:2898 [inline]
 pagetable_dtor_free include/linux/mm.h:2996 [inline]
 __tlb_remove_table+0x2d2/0x3b0 include/asm-generic/tlb.h:220
 __tlb_remove_table_free mm/mmu_gather.c:227 [inline]
 tlb_remove_table_rcu+0x85/0x100 mm/mmu_gather.c:290
 rcu_do_batch kernel/rcu/tree.c:2605 [inline]
 rcu_core kernel/rcu/tree.c:2861 [inline]
 rcu_cpu_kthread+0xbf3/0x1b50 kernel/rcu/tree.c:2949
 smpboot_thread_fn+0x53f/0xa60 kernel/smpboot.c:160
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff8880112b8900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880112b8980: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff8880112b8a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff8880112b8a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880112b8b00: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
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