EXT4-fs error (device loop0): ext4_ext_check_inode:501: inode #17: comm syz-executor428: pblk 0 bad header/extent: invalid magic - magic 0, entries 0, max 0(0), depth 0(0)
EXT4-fs error (device loop0): ext4_ext_check_inode:501: inode #17: comm syz-executor428: pblk 0 bad header/extent: invalid magic - magic 0, entries 0, max 0(0), depth 0(0)
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BUG: KASAN: use-after-free in ext4_ext_rm_leaf fs/ext4/extents.c:2599 [inline]
BUG: KASAN: use-after-free in ext4_ext_remove_space+0x3bb4/0x4a60 fs/ext4/extents.c:2937
Read of size 4 at addr ffff8881231ad01c by task syz-executor428/297

CPU: 1 PID: 297 Comm: syz-executor428 Not tainted 5.15.178-syzkaller-00013-g7d1f9b5c2ff5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x151/0x1c0 lib/dump_stack.c:106
 print_address_description+0x87/0x3b0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:427 [inline]
 kasan_report+0x179/0x1c0 mm/kasan/report.c:444
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 ext4_ext_rm_leaf fs/ext4/extents.c:2599 [inline]
 ext4_ext_remove_space+0x3bb4/0x4a60 fs/ext4/extents.c:2937
 ext4_ext_truncate+0x19a/0x240 fs/ext4/extents.c:4471
 ext4_truncate+0x96c/0xfa0 fs/ext4/inode.c:4280
 ext4_evict_inode+0xcee/0x14e0 fs/ext4/inode.c:290
 evict+0x529/0x930 fs/inode.c:622
 iput_final fs/inode.c:1744 [inline]
 iput+0x63b/0x7e0 fs/inode.c:1770
 dentry_unlink_inode+0x34e/0x430 fs/dcache.c:380
 __dentry_kill+0x447/0x660 fs/dcache.c:586
 shrink_dentry_list+0x35e/0x4b0 fs/dcache.c:1181
 shrink_dcache_parent+0xc9/0x340
 do_one_tree+0x27/0xe0 fs/dcache.c:1662
 shrink_dcache_for_umount+0x7d/0x120 fs/dcache.c:1679
 generic_shutdown_super+0x66/0x330 fs/super.c:447
 kill_block_super+0x7e/0xe0 fs/super.c:1427
 deactivate_locked_super+0xad/0x110 fs/super.c:335
 deactivate_super+0xbe/0xf0 fs/super.c:366
 cleanup_mnt+0x45c/0x510 fs/namespace.c:1143
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1150
 task_work_run+0x129/0x190 kernel/task_work.c:188
 exit_task_work include/linux/task_work.h:33 [inline]
 do_exit+0xc48/0x2ca0 kernel/exit.c:880
 do_group_exit+0x141/0x310 kernel/exit.c:1002
 __do_sys_exit_group kernel/exit.c:1013 [inline]
 __se_sys_exit_group kernel/exit.c:1011 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1011
 x64_sys_call+0x610/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f92ff631839
Code: Unable to access opcode bytes at RIP 0x7f92ff63180f.
RSP: 002b:00007ffeb9190a58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f92ff631839
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000001
RBP: 00007f92ff6af150 R08: ffffffffffffffb8 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000246 R12: 00007f92ff6af150
R13: 0000000000000000 R14: 00007f92ff6b1f80 R15: 00007f92ff5f6e80
 </TASK>

The buggy address belongs to the page:
page:ffffea00048c6b40 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x1231ad
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 ffffea00048c6b88 ffffea00048c6b08 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 0x100dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), pid 247, ts 17578513474, free_ts 17615846386
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1a3/0x1b0 mm/page_alloc.c:2605
 prep_new_page+0x1b/0x110 mm/page_alloc.c:2611
 get_page_from_freelist+0x3550/0x35d0 mm/page_alloc.c:4485
 __alloc_pages+0x27e/0x8f0 mm/page_alloc.c:5780
 __alloc_pages_node include/linux/gfp.h:591 [inline]
 alloc_pages_node include/linux/gfp.h:605 [inline]
 alloc_pages include/linux/gfp.h:618 [inline]
 do_anonymous_page mm/memory.c:4066 [inline]
 handle_pte_fault+0xec8/0x28f0 mm/memory.c:4906
 do_handle_mm_fault+0x20bc/0x2400 mm/memory.c:5330
 handle_mm_fault include/linux/mm.h:1836 [inline]
 do_user_addr_fault arch/x86/mm/fault.c:1418 [inline]
 handle_page_fault arch/x86/mm/fault.c:1509 [inline]
 exc_page_fault+0x3b5/0x7f0 arch/x86/mm/fault.c:1565
 asm_exc_page_fault+0x27/0x30 arch/x86/include/asm/idtentry.h:606
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1472 [inline]
 free_pcp_prepare mm/page_alloc.c:1544 [inline]
 free_unref_page_prepare+0x7c8/0x7d0 mm/page_alloc.c:3534
 free_unref_page_list+0x14b/0xa60 mm/page_alloc.c:3671
 release_pages+0x1310/0x1370 mm/swap.c:1009
 free_pages_and_swap_cache+0x8a/0xa0 mm/swap_state.c:320
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
 tlb_flush_mmu mm/mmu_gather.c:247 [inline]
 tlb_finish_mmu+0x177/0x320 mm/mmu_gather.c:338
 unmap_region+0x304/0x350 mm/mmap.c:2680
 __do_munmap+0x13e4/0x19d0 mm/mmap.c:2913
 __vm_munmap+0x166/0x2a0 mm/mmap.c:2966
 __do_sys_munmap mm/mmap.c:2992 [inline]
 __se_sys_munmap mm/mmap.c:2988 [inline]
 __x64_sys_munmap+0x6b/0x80 mm/mmap.c:2988
 x64_sys_call+0x75/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:12
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff8881231acf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881231acf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881231ad000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                            ^
 ffff8881231ad080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881231ad100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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