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BUG: KASAN: use-after-free in ext4_data_block_valid+0x17f/0x2d0 fs/ext4/block_validity.c:261
Read of size 8 at addr ffff8882160dc5c8 by task syz-executor.0/3840

CPU: 0 PID: 3840 Comm: syz-executor.0 Not tainted 5.2.0-rc6+ #7
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1d8/0x2f8 lib/dump_stack.c:113
 print_address_description+0x6d/0x310 mm/kasan/report.c:188
 __kasan_report+0x14b/0x1c0 mm/kasan/report.c:317
 kasan_report+0x26/0x50 mm/kasan/common.c:614
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
 ext4_data_block_valid+0x17f/0x2d0 fs/ext4/block_validity.c:261
 __check_block_validity fs/ext4/inode.c:406 [inline]
 ext4_map_blocks+0x7bf/0x1cd0 fs/ext4/inode.c:596
 ext4_getblk fs/ext4/inode.c:968 [inline]
 ext4_bread_batch+0x180/0x790 fs/ext4/inode.c:1038
 __ext4_find_entry+0xe54/0x1ae0 fs/ext4/namei.c:1466
 ext4_lookup_entry fs/ext4/namei.c:1565 [inline]
 ext4_lookup+0x34b/0xa40 fs/ext4/namei.c:1633
 __lookup_hash+0x141/0x290 fs/namei.c:1544
 filename_create+0x1c6/0x6f0 fs/namei.c:3635
 user_path_create fs/namei.c:3692 [inline]
 do_symlinkat+0xd1/0x480 fs/namei.c:4145
 __do_sys_symlink fs/namei.c:4171 [inline]
 __se_sys_symlink fs/namei.c:4169 [inline]
 __x64_sys_symlink+0x60/0x70 fs/namei.c:4169
 do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459247
Code: 0f 1f 00 b8 5c 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 bd ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 58 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 9d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffe3e726cb8 EFLAGS: 00000206 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000459247
RDX: 00007ffe3e726d57 RSI: 00000000004bed0b RDI: 00007ffe3e726d40
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000017
R10: 0000000000000075 R11: 0000000000000206 R12: 0000000000000001
R13: 00007ffe3e726cf0 R14: 0000000000000000 R15: 00007ffe3e726d00

Allocated by task 1:
 save_stack mm/kasan/common.c:71 [inline]
 set_track mm/kasan/common.c:79 [inline]
 __kasan_kmalloc+0x11c/0x1b0 mm/kasan/common.c:489
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:497
 slab_post_alloc_hook mm/slab.h:437 [inline]
 slab_alloc mm/slab.c:3326 [inline]
 kmem_cache_alloc+0x1dd/0x2b0 mm/slab.c:3488
 add_system_zone+0x168/0x610 fs/ext4/block_validity.c:85
 ext4_setup_system_zone+0x431/0xf40 fs/ext4/block_validity.c:213
 ext4_fill_super+0xae63/0xe650 fs/ext4/super.c:4493
 mount_bdev+0x31c/0x440 fs/super.c:1346
 ext4_mount+0x34/0x40 fs/ext4/super.c:6007
 legacy_get_tree+0xf9/0x1a0 fs/fs_context.c:661
 vfs_get_tree+0x8f/0x360 fs/super.c:1476
 do_new_mount fs/namespace.c:2791 [inline]
 do_mount+0x1813/0x2730 fs/namespace.c:3111
 ksys_mount+0xcc/0x100 fs/namespace.c:3320
 do_mount_root+0x35/0x1af init/do_mounts.c:389
 mount_block_root+0x109/0x404 init/do_mounts.c:418
 mount_root+0x166/0x18b init/do_mounts.c:563
 prepare_namespace+0x294/0x299 init/do_mounts.c:622
 kernel_init_freeable+0x3a6/0x481 init/main.c:1188
 kernel_init+0x11/0x3b0 init/main.c:1087
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Freed by task 3831:
 save_stack mm/kasan/common.c:71 [inline]
 set_track mm/kasan/common.c:79 [inline]
 __kasan_slab_free+0x12a/0x1e0 mm/kasan/common.c:451
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459
 __cache_free mm/slab.c:3432 [inline]
 kmem_cache_free+0xcb/0x170 mm/slab.c:3698
 ext4_release_system_zone fs/ext4/block_validity.c:237 [inline]
 ext4_setup_system_zone+0x1b2/0xf40 fs/ext4/block_validity.c:194
 ext4_remount+0x1785/0x31a0 fs/ext4/super.c:5452
 legacy_reconfigure+0x104/0x110 fs/fs_context.c:684
 reconfigure_super+0x3cc/0x800 fs/super.c:986
 do_remount fs/namespace.c:2533 [inline]
 do_mount+0x1bf1/0x2730 fs/namespace.c:3102
 ksys_mount+0xcc/0x100 fs/namespace.c:3320
 __do_sys_mount fs/namespace.c:3334 [inline]
 __se_sys_mount fs/namespace.c:3331 [inline]
 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3331
 do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8882160dc5b0
 which belongs to the cache ext4_system_zone of size 40
The buggy address is located 24 bytes inside of
 40-byte region [ffff8882160dc5b0, ffff8882160dc5d8)
The buggy address belongs to the page:
page:ffffea0008583700 refcount:1 mapcount:0 mapping:ffff8880a5916240 index:0xffff8882160dcfb9
flags: 0x6fffc0000000200(slab)
raw: 06fffc0000000200 ffff888219987938 ffff888219987938 ffff8880a5916240
raw: ffff8882160dcfb9 ffff8882160dc000 000000010000001b 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8882160dc480: fb fc fc fb fb fb fb fb fc fc fb fb fb fb fb fc
 ffff8882160dc500: fc fb fb fb fb fb fc fc fb fb fb fb fb fc fc fb
>ffff8882160dc580: fb fb fb fb fc fc fb fb fb fb fb fc fc fc fc fc
                                              ^
 ffff8882160dc600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8882160dc680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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