================================================================== 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 ffff888126723db8 by task syz-executor/470 CPU: 0 PID: 470 Comm: syz-executor Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 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:4367 ext4_evict_inode+0xf4f/0x1760 fs/ext4/inode.c:290 evict+0x478/0x910 fs/inode.c:612 iput_final fs/inode.c:1736 [inline] iput+0x638/0x7c0 fs/inode.c:1762 do_unlinkat+0x33f/0x670 fs/namei.c:4042 __do_sys_unlink fs/namei.c:4082 [inline] __se_sys_unlink fs/namei.c:4080 [inline] __x64_sys_unlink+0x49/0x50 fs/namei.c:4080 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f2747749197 Code: 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 57 00 00 00 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:00007ffead7d9bb8 EFLAGS: 00000206 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2747749197 RDX: 00007ffead7d9be0 RSI: 00007ffead7d9c70 RDI: 00007ffead7d9c70 RBP: 00007ffead7d9c70 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffead7dad60 R13: 00007f27477ccc05 R14: 000000000000c097 R15: 00007ffead7dbe30 The buggy address belongs to the page: page:ffffea000499c8c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x126723 flags: 0x4000000000000000() raw: 4000000000000000 ffffea000499c908 ffffea000499c888 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 0x101cca(GFP_HIGHUSER_MOVABLE|__GFP_WRITE), pid 475, ts 49327262939, free_ts 49465470951 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] __page_cache_alloc include/linux/pagemap.h:290 [inline] pagecache_get_page+0x642/0x930 mm/filemap.c:1848 grab_cache_page_write_begin+0x59/0xb0 mm/filemap.c:3459 ext4_write_begin+0x27b/0x15a0 fs/ext4/inode.c:1208 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_write+0x140/0x240 fs/read_write.c:658 __do_sys_write fs/read_write.c:670 [inline] __se_sys_write fs/read_write.c:667 [inline] __x64_sys_write+0x7b/0x90 fs/read_write.c:667 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb 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] truncate_inode_pages_range+0x771/0x15b0 mm/truncate.c:367 truncate_inode_pages mm/truncate.c:473 [inline] truncate_pagecache+0x6c/0x90 mm/truncate.c:834 ext4_setattr+0xdf0/0x1760 fs/ext4/inode.c:5676 notify_change+0xab3/0xe40 fs/attr.c:410 do_truncate+0x186/0x210 fs/open.c:65 do_sys_ftruncate+0x495/0x6b0 fs/open.c:196 __do_sys_ftruncate fs/open.c:206 [inline] __se_sys_ftruncate fs/open.c:204 [inline] __x64_sys_ftruncate+0x60/0x70 fs/open.c:204 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb Memory state around the buggy address: ffff888126723c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888126723d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff888126723d80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff888126723e00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888126723e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 36577312, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 36577312, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 2 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 21249056, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 1 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 2, count = 192 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 107130969641600, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 107130969614704, count = 26912 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 107130969614704, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 54117517150864, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 54117517124658, count = 26214 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 54117517124656, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 121398968610512, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 121398968584807, count = 25710 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 1, count = 192 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 1842540970176, count = 23824 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 36577312, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 36577312, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 21249456, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 1 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 50397184, count = 192 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 2396591751168, count = 8224 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 50397184, count = 192 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 2396591751168, count = 8224 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 107165440984272, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 107165440959851, count = 24436 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 107165440959840, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 123662517000368, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 123662516974431, count = 25951 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 106899389309280, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 106899389296693, count = 12597 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 106899389296688, count = 16