EXT4-fs (loop7): pa ffff88810ffc0e70: logic 128, phys. 385, len 8
EXT4-fs error (device loop7): ext4_mb_release_inode_pa:4359: group 0, free 0, pa_free 1
==================================================================
BUG: KASAN: use-after-free in ext4_ext_rm_leaf fs/ext4/extents.c:2596 [inline]
BUG: KASAN: use-after-free in ext4_ext_remove_space+0x3a6a/0x4920 fs/ext4/extents.c:2934
Read of size 4 at addr ffff888146f22c18 by task syz.7.3755/14568

CPU: 0 PID: 14568 Comm: syz.7.3755 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 __dump_stack+0x21/0x24 lib/dump_stack.c:77
 dump_stack_lvl+0x169/0x1d8 lib/dump_stack.c:118
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0xe2/0x130 mm/kasan/report.c:452
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 ext4_ext_rm_leaf fs/ext4/extents.c:2596 [inline]
 ext4_ext_remove_space+0x3a6a/0x4920 fs/ext4/extents.c:2934
 ext4_ext_truncate+0x169/0x1f0 fs/ext4/extents.c:4467
 ext4_truncate+0xaea/0x1290 fs/ext4/inode.c:4373
 ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
 ext4_write_begin+0xd78/0x15a0 fs/ext4/inode.c:1276
 ext4_da_write_begin+0x455/0xe80 fs/ext4/inode.c:3033
 generic_perform_write+0x2be/0x510 mm/filemap.c:3509
 ext4_buffered_write_iter+0x4b8/0x640 fs/ext4/file.c:271
 ext4_file_write_iter+0x536/0x1980 fs/ext4/file.c:-1
 call_write_iter include/linux/fs.h:2066 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x725/0xd60 fs/read_write.c:605
 ksys_pwrite64 fs/read_write.c:712 [inline]
 __do_sys_pwrite64 fs/read_write.c:722 [inline]
 __se_sys_pwrite64 fs/read_write.c:719 [inline]
 __x64_sys_pwrite64+0x191/0x220 fs/read_write.c:719
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f942005e749
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:00007f941eac6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007f94202b4fa0 RCX: 00007f942005e749
RDX: 00000000200000c1 RSI: 00002000000000c0 RDI: 0000000000000006
RBP: 00007f94200e2f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000009000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f94202b5038 R14: 00007f94202b4fa0 R15: 00007ffeb059a868

The buggy address belongs to the page:
page:ffffea00051bc880 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x146f22
flags: 0x4000000000000000()
raw: 4000000000000000 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 0x100cca(GFP_HIGHUSER_MOVABLE), pid 8955, ts 341706398089, free_ts 343628870556
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x179/0x180 mm/page_alloc.c:2462
 get_page_from_freelist+0x2235/0x23d0 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x268/0x5f0 mm/page_alloc.c:5370
 __alloc_pages include/linux/gfp.h:544 [inline]
 __alloc_pages_node include/linux/gfp.h:557 [inline]
 alloc_pages_node include/linux/gfp.h:571 [inline]
 alloc_pages include/linux/gfp.h:590 [inline]
 shmem_alloc_page+0x1b1/0x300 mm/shmem.c:1584
 shmem_alloc_and_acct_page+0x36f/0x7b0 mm/shmem.c:1609
 shmem_getpage_gfp+0x625/0x2110 mm/shmem.c:1922
 shmem_getpage mm/shmem.c:165 [inline]
 shmem_write_begin+0xce/0x1b0 mm/shmem.c:2501
 generic_perform_write+0x2be/0x510 mm/filemap.c:3509
 __generic_file_write_iter+0x24b/0x480 mm/filemap.c:3638
 generic_file_write_iter+0xa9/0x1d0 mm/filemap.c:3670
 __kernel_write+0x55a/0x910 fs/read_write.c:550
 dump_emit+0x240/0x360 fs/coredump.c:855
 dump_user_range+0x6a/0x1a0 fs/coredump.c:908
 elf_core_dump+0x278a/0x2bc0 fs/binfmt_elf.c:2290
 do_coredump+0x1ac9/0x27f0 fs/coredump.c:817
 get_signal+0xf23/0x12e0 kernel/signal.c:2779
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1349 [inline]
 free_pcp_prepare mm/page_alloc.c:1421 [inline]
 free_unref_page_prepare+0x2b7/0x2d0 mm/page_alloc.c:3336
 free_unref_page_list+0x12e/0x9b0 mm/page_alloc.c:3443
 release_pages+0xe38/0xe80 mm/swap.c:1103
 __pagevec_release+0x71/0xe0 mm/swap.c:1123
 pagevec_release include/linux/pagevec.h:88 [inline]
 shmem_undo_range+0x6e1/0x1760 mm/shmem.c:969
 shmem_truncate_range mm/shmem.c:1073 [inline]
 shmem_evict_inode+0x1fd/0x9c0 mm/shmem.c:1173
 evict+0x478/0x910 fs/inode.c:612
 iput_final fs/inode.c:1736 [inline]
 iput+0x638/0x7c0 fs/inode.c:1762
 dentry_unlink_inode+0x2cf/0x380 fs/dcache.c:378
 __dentry_kill+0x44f/0x650 fs/dcache.c:583
 dentry_kill+0xc0/0x2a0 fs/dcache.c:-1
 dput+0x42/0x80 fs/dcache.c:883
 __fput+0x4fe/0x770 fs/file_table.c:294
 ____fput+0x15/0x20 fs/file_table.c:314
 task_work_run+0x127/0x190 kernel/task_work.c:189
 exit_task_work include/linux/task_work.h:33 [inline]
 do_exit+0xa4f/0x2480 kernel/exit.c:872

Memory state around the buggy address:
 ffff888146f22b00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888146f22b80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888146f22c00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                            ^
 ffff888146f22c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888146f22d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs error (device loop7): ext4_free_blocks:5685: comm syz.7.3755: Freeing blocks not in datazone - block = 281472851884112, count = 16
EXT4-fs error (device loop7): ext4_free_blocks:5685: comm syz.7.3755: Freeing blocks not in datazone - block = 281472851851352, count = 32767
EXT4-fs error (device loop7): ext4_free_blocks:5685: comm syz.7.3755: Freeing blocks not in datazone - block = 281472851884112, count = 16
EXT4-fs error (device loop7): ext4_free_blocks:5685: comm syz.7.3755: Freeing blocks not in datazone - block = 281472851851352, count = 32767
EXT4-fs error (device loop7): ext4_free_blocks:5685: comm syz.7.3755: Freeing blocks not in datazone - block = 281472851884112, count = 16
EXT4-fs error (device loop7): ext4_free_blocks:5685: comm syz.7.3755: Freeing blocks not in datazone - block = 281472851851352, count = 32767
EXT4-fs error (device loop7): ext4_free_blocks:5685: comm syz.7.3755: Freeing blocks not in datazone - block = 281472851884112, count = 16
EXT4-fs error (device loop7): ext4_free_blocks:5685: comm syz.7.3755: Freeing blocks not in datazone - block = 281472851851352, count = 32767