================================================================== 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 ffff88812b4f1db8 by task syz-executor/353 CPU: 1 PID: 353 Comm: syz-executor Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2025 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: 0033:0x7f834bea7197 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:00007fffd1bdd038 EFLAGS: 00000206 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f834bea7197 RDX: 00007fffd1bdd060 RSI: 00007fffd1bdd0f0 RDI: 00007fffd1bdd0f0 RBP: 00007fffd1bdd0f0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000206 R12: 00007fffd1bde1e0 R13: 00007f834bf2ac05 R14: 0000000000008278 R15: 00007fffd1bdf2b0 The buggy address belongs to the page: page:ffffea0004ad3c40 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x12b4f1 flags: 0x4000000000000000() raw: 4000000000000000 ffffea0004ad3c88 ffffea0004ad3c08 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 383, ts 33418754773, free_ts 33452919561 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: ffff88812b4f1c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88812b4f1d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff88812b4f1d80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff88812b4f1e00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88812b4f1e80: 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 = 1, 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 = 1, 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 = 2383706849472, count = 18464 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 = 280588255311792, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 280588255295025, count = 16777 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 280588255295024, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 216068140541408, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 216068140522784, count = 18633 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 216068140522784, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 79991774187664, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 79991774175113, count = 12562 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 74920640, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 74920640, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 130178150156496, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 130178150130783, count = 25714 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 130178150130768, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 126905033740752, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 126905033716340, count = 24415 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 126905033716336, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 106881123184016, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 106881123169588, count = 14438 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 74953184, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 74920640, count = 32558 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 5068061431242, count = 1936 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 184918795698304, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 184918795691850, count = 6464 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 184918795691840, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 191528750389152, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 191528750372676, count = 16489 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 191528750372672, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 131106601843776, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz-executor: Freeing blocks not in datazone - block = 131106601841195, count = 2590