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BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:837 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0xbc8/0xde0 fs/ext4/extents.c:953
Read of size 4 at addr ffff888041b99678 by task syz-executor.4/11868

CPU: 1 PID: 11868 Comm: syz-executor.4 Not tainted 6.4.0-syzkaller-12365-g8689f4f2ea56 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/03/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0x163/0x540 mm/kasan/report.c:475
 kasan_report+0x175/0x1b0 mm/kasan/report.c:588
 ext4_ext_binsearch fs/ext4/extents.c:837 [inline]
 ext4_find_extent+0xbc8/0xde0 fs/ext4/extents.c:953
 ext4_ext_map_blocks+0x2d1/0x71d0 fs/ext4/extents.c:4101
 ext4_map_blocks+0xa2f/0x1cb0 fs/ext4/inode.c:621
 _ext4_get_block+0x238/0x6a0 fs/ext4/inode.c:763
 __block_write_begin_int+0x555/0x1a60 fs/buffer.c:2128
 block_page_mkwrite+0x29d/0x4e0 fs/buffer.c:2651
 ext4_page_mkwrite+0x500/0x1290 fs/ext4/inode.c:6116
 do_page_mkwrite+0x1a4/0x600 mm/memory.c:2942
 wp_page_shared mm/memory.c:3294 [inline]
 do_wp_page+0x559/0x3a70 mm/memory.c:3376
 handle_pte_fault mm/memory.c:4948 [inline]
 __handle_mm_fault mm/memory.c:5072 [inline]
 handle_mm_fault+0x1c58/0x5410 mm/memory.c:5226
 do_user_addr_fault arch/x86/mm/fault.c:1392 [inline]
 handle_page_fault arch/x86/mm/fault.c:1486 [inline]
 exc_page_fault+0x266/0x7c0 arch/x86/mm/fault.c:1542
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
RIP: 0033:0x7feb81086ed6
Code: 4c 29 c7 4c 01 c2 48 3b 15 e7 3f c5 00 0f 87 cc 00 00 00 0f 10 06 0f 10 4e 10 0f 10 56 20 0f 10 5e 30 48 83 c6 40 48 83 ea 40 <0f> 29 07 0f 29 4f 10 0f 29 57 20 0f 29 5f 30 48 83 c7 40 48 83 fa
RSP: 002b:00007ffde04d9cb8 EFLAGS: 00010202
RAX: 0000000020001b00 RBX: 0000000000000000 RCX: 0000000020001fa4
RDX: 0000000000000464 RSI: 00007feb80c20b08 RDI: 0000000020001b10
RBP: 00007ffde04d9d78 R08: fffffffffffffff0 R09: 00007feb80c00000
R10: 00007feb80c20aa0 R11: 0000000020001b00 R12: 00000000001388a1
R13: 00007ffde04d9da0 R14: 00007feb811ac050 R15: 0000000000000032
 </TASK>

The buggy address belongs to the physical page:
page:ffffea000106e640 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x41b99
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_COMP|__GFP_ZERO), pid 11628, tgid 11626 (syz-executor.4), ts 1273920141980, free_ts 1274635033220
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1e6/0x210 mm/page_alloc.c:1570
 prep_new_page mm/page_alloc.c:1577 [inline]
 get_page_from_freelist+0x31e8/0x3370 mm/page_alloc.c:3221
 __alloc_pages+0x255/0x670 mm/page_alloc.c:4477
 __folio_alloc+0x13/0x30 mm/page_alloc.c:4509
 vma_alloc_folio+0x48a/0x9a0 mm/mempolicy.c:2240
 do_anonymous_page mm/memory.c:4097 [inline]
 do_pte_missing mm/memory.c:3662 [inline]
 handle_pte_fault mm/memory.c:4932 [inline]
 __handle_mm_fault mm/memory.c:5072 [inline]
 handle_mm_fault+0x20c7/0x5410 mm/memory.c:5226
 do_user_addr_fault arch/x86/mm/fault.c:1392 [inline]
 handle_page_fault arch/x86/mm/fault.c:1486 [inline]
 exc_page_fault+0x266/0x7c0 arch/x86/mm/fault.c:1542
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1161 [inline]
 free_unref_page_prepare+0x903/0xa30 mm/page_alloc.c:2348
 free_unref_page_list+0x596/0x830 mm/page_alloc.c:2489
 release_pages+0x2193/0x2470 mm/swap.c:1042
 tlb_batch_pages_flush mm/mmu_gather.c:97 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:292 [inline]
 tlb_flush_mmu+0x100/0x210 mm/mmu_gather.c:299
 zap_pte_range mm/memory.c:1531 [inline]
 zap_pmd_range mm/memory.c:1570 [inline]
 zap_pud_range mm/memory.c:1599 [inline]
 zap_p4d_range mm/memory.c:1620 [inline]
 unmap_page_range+0x23e2/0x2940 mm/memory.c:1641
 unmap_vmas+0x347/0x4e0 mm/memory.c:1726
 exit_mmap+0x25e/0xad0 mm/mmap.c:3196
 __mmput+0x115/0x3c0 kernel/fork.c:1347
 exit_mm+0x21f/0x300 kernel/exit.c:567
 do_exit+0x612/0x2290 kernel/exit.c:861
 do_group_exit+0x206/0x2c0 kernel/exit.c:1024
 __do_sys_exit_group kernel/exit.c:1035 [inline]
 __se_sys_exit_group kernel/exit.c:1033 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1033
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
 ffff888041b99500: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888041b99580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888041b99600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                                ^
 ffff888041b99680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888041b99700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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