================================================================== BUG: KASAN: slab-out-of-bounds in ext4_ext_correct_indexes+0x72/0x5b0 fs/ext4/extents.c:1712 Read of size 8 at addr ffff888020ea00d0 by task syz.0.638/9291 CPU: 0 UID: 0 PID: 9291 Comm: syz.0.638 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: 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 ext4_ext_correct_indexes+0x72/0x5b0 fs/ext4/extents.c:1712 ext4_ext_insert_extent+0x1fdd/0x4af0 fs/ext4/extents.c:2188 ext4_ext_map_blocks+0x1792/0x6ac0 fs/ext4/extents.c:4404 ext4_map_create_blocks fs/ext4/inode.c:609 [inline] ext4_map_blocks+0x860/0x1740 fs/ext4/inode.c:811 _ext4_get_block+0x200/0x4c0 fs/ext4/inode.c:910 ext4_get_block_unwritten+0x2e/0x100 fs/ext4/inode.c:943 ext4_block_write_begin+0x993/0x1710 fs/ext4/inode.c:1198 ext4_write_begin+0xc04/0x19a0 fs/ext4/ext4_jbd2.h:-1 ext4_da_write_begin+0x445/0xdb0 fs/ext4/inode.c:3129 generic_perform_write+0x29d/0x8c0 mm/filemap.c:4242 ext4_buffered_write_iter+0xd0/0x3a0 fs/ext4/file.c:299 ext4_file_write_iter+0x299/0x1be0 fs/ext4/file.c:-1 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5d5/0xb40 fs/read_write.c:686 ksys_pwrite64 fs/read_write.c:793 [inline] __do_sys_pwrite64 fs/read_write.c:801 [inline] __se_sys_pwrite64 fs/read_write.c:798 [inline] __x64_sys_pwrite64+0x196/0x220 fs/read_write.c:798 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f25676ae969 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:00007f256691e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000012 RAX: ffffffffffffffda RBX: 00007f25678d5fa0 RCX: 00007f25676ae969 RDX: 000000000000fdef RSI: 0000200000000140 RDI: 0000000000000004 RBP: 00007f2567730ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000fecc R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f25678d5fa0 R15: 00007ffc2084e658 Allocated by task 6216: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:400 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417 kasan_kmalloc include/linux/kasan.h:262 [inline] __do_kmalloc_node mm/slub.c:5646 [inline] __kmalloc_node_noprof+0x398/0x7f0 mm/slub.c:5652 kmalloc_array_node_noprof include/linux/slab.h:1075 [inline] alloc_slab_obj_exts+0x3e/0x100 mm/slub.c:2123 __memcg_slab_post_alloc_hook+0x33b/0x810 mm/memcontrol.c:3173 memcg_slab_post_alloc_hook mm/slub.c:2338 [inline] slab_post_alloc_hook mm/slub.c:4985 [inline] slab_alloc_node mm/slub.c:5284 [inline] kmem_cache_alloc_noprof+0x41f/0x6b0 mm/slub.c:5291 copy_signal+0x50/0x670 kernel/fork.c:1659 copy_process+0x16a4/0x3ae0 kernel/fork.c:2178 kernel_clone+0x224/0x7c0 kernel/fork.c:2609 __do_sys_clone kernel/fork.c:2750 [inline] __se_sys_clone kernel/fork.c:2734 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2734 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888020ea0000 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 72 bytes to the right of allocated 136-byte region [ffff888020ea0000, ffff888020ea0088) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x20ea0 anon flags: 0x80000000000000(node=0|zone=1) page_type: f5(slab) raw: 0080000000000000 ffff88813ff263c0 0000000000000000 dead000000000001 raw: 0000000000000000 0000000000100010 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 1, tgid 1 (swapper/0), ts 3845084183, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x28c0/0x2960 mm/page_alloc.c:3884 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:3055 [inline] allocate_slab+0x96/0x350 mm/slub.c:3228 new_slab mm/slub.c:3282 [inline] ___slab_alloc+0xb10/0x1400 mm/slub.c:4651 __slab_alloc+0xc6/0x1f0 mm/slub.c:4774 __slab_alloc_node mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:5272 [inline] __kmalloc_cache_noprof+0xec/0x6c0 mm/slub.c:5762 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] call_usermodehelper_setup+0x8e/0x270 kernel/umh.c:362 kobject_uevent_env+0x65f/0x8c0 lib/kobject_uevent.c:628 device_add+0x557/0xb50 drivers/base/core.c:3670 pci_device_add+0xd65/0x14b0 drivers/pci/probe.c:2762 pci_scan_single_device+0x286/0x360 drivers/pci/probe.c:2784 pci_scan_slot+0x1e3/0x590 drivers/pci/probe.c:2867 pci_scan_child_bus_extend+0x5e/0x720 drivers/pci/probe.c:3086 acpi_pci_root_create+0xa75/0xca0 drivers/acpi/pci_root.c:1049 page_owner free stack trace missing Memory state around the buggy address: ffff888020e9ff80: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc ffff888020ea0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff888020ea0080: 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff888020ea0100: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888020ea0180: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc 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