================================================================== BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:826 [inline] BUG: KASAN: use-after-free in ext4_find_extent+0xbea/0xe30 fs/ext4/extents.c:945 Read of size 4 at addr ffff8881348ea84c by task kworker/u4:4/525 CPU: 1 PID: 525 Comm: kworker/u4:4 Not tainted 5.10.234-syzkaller-00033-g094fc3778d6b #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: writeback wb_workfn (flush-7:5) Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118 print_address_description+0x81/0x3b0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:435 [inline] kasan_report+0x179/0x1c0 mm/kasan/report.c:452 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308 ext4_ext_binsearch fs/ext4/extents.c:826 [inline] ext4_find_extent+0xbea/0xe30 fs/ext4/extents.c:945 ext4_ext_map_blocks+0x26a/0x6ee0 fs/ext4/extents.c:4159 ext4_map_blocks+0xa65/0x1d10 fs/ext4/inode.c:673 mpage_map_one_extent fs/ext4/inode.c:2451 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2504 [inline] ext4_writepages+0x148b/0x3c00 fs/ext4/inode.c:2872 do_writepages+0x12e/0x270 mm/page-writeback.c:2380 __writeback_single_inode+0xd7/0xac0 fs/fs-writeback.c:1470 writeback_sb_inodes+0x99c/0x16b0 fs/fs-writeback.c:1733 wb_writeback+0x404/0xc60 fs/fs-writeback.c:1908 wb_do_writeback fs/fs-writeback.c:2053 [inline] wb_workfn+0x3d9/0x1110 fs/fs-writeback.c:2094 process_one_work+0x6dc/0xbd0 kernel/workqueue.c:2301 worker_thread+0xaea/0x1510 kernel/workqueue.c:2447 kthread+0x34b/0x3d0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 The buggy address belongs to the page: page:ffffea0004d23a80 refcount:1 mapcount:0 mapping:ffff888115a3a630 index:0x117a pfn:0x1348ea aops:shmem_aops ino:c1 dentry name:"memfd:syzkaller" flags: 0x400000000008001e(referenced|uptodate|dirty|lru|swapbacked) raw: 400000000008001e ffffea0004d23a48 ffffea0004d23ac8 ffff888115a3a630 raw: 000000000000117a 0000000000000000 00000001ffffffff ffff888119868000 page dumped because: kasan: bad access detected page->mem_cgroup:ffff888119868000 page_owner tracks the page as allocated page last allocated via order 0, migratetype Movable, gfp_mask 0x100cca(GFP_HIGHUSER_MOVABLE), pid 3618, ts 141403621983, free_ts 141218389144 set_page_owner include/linux/page_owner.h:35 [inline] post_alloc_hook mm/page_alloc.c:2456 [inline] prep_new_page+0x166/0x180 mm/page_alloc.c:2462 get_page_from_freelist+0x2d8c/0x2f30 mm/page_alloc.c:4254 __alloc_pages_nodemask+0x435/0xaf0 mm/page_alloc.c:5348 __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+0x257/0x420 mm/shmem.c:1580 shmem_alloc_and_acct_page+0x395/0x8e0 mm/shmem.c:1605 shmem_getpage_gfp+0x891/0x2480 mm/shmem.c:1918 shmem_getpage mm/shmem.c:161 [inline] shmem_write_begin+0xca/0x1b0 mm/shmem.c:2497 generic_perform_write+0x2cd/0x570 mm/filemap.c:3509 __generic_file_write_iter+0x23c/0x560 mm/filemap.c:3638 generic_file_write_iter+0xaf/0x1c0 mm/filemap.c:3670 call_write_iter include/linux/fs.h:2058 [inline] new_sync_write fs/read_write.c:518 [inline] vfs_write+0xb4c/0xe70 fs/read_write.c:605 ksys_write+0x199/0x2c0 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+0x34/0x70 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+0x2ae/0x2d0 mm/page_alloc.c:3336 free_unref_page_list+0x122/0xb20 mm/page_alloc.c:3443 release_pages+0xea0/0xef0 mm/swap.c:1103 __pagevec_release+0x84/0x100 mm/swap.c:1123 pagevec_release include/linux/pagevec.h:88 [inline] shmem_undo_range+0x7d1/0x1a60 mm/shmem.c:965 shmem_truncate_range mm/shmem.c:1069 [inline] shmem_evict_inode+0x215/0x9d0 mm/shmem.c:1169 evict+0x526/0x9c0 fs/inode.c:612 iput_final fs/inode.c:1736 [inline] iput+0x632/0x7e0 fs/inode.c:1762 dentry_unlink_inode+0x2ea/0x3d0 fs/dcache.c:378 __dentry_kill+0x447/0x650 fs/dcache.c:583 dentry_kill+0xc0/0x2a0 dput+0x40/0x80 fs/dcache.c:883 __fput+0x52e/0x7b0 fs/file_table.c:294 ____fput+0x15/0x20 fs/file_table.c:314 task_work_run+0x129/0x190 kernel/task_work.c:189 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0xc83/0x2a50 kernel/exit.c:863 Memory state around the buggy address: ffff8881348ea700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8881348ea780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8881348ea800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ^ ffff8881348ea880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8881348ea900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ================================================================== ------------[ cut here ]------------ kernel BUG at fs/ext4/inode.c:2463! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 525 Comm: kworker/u4:4 Tainted: G B 5.10.234-syzkaller-00033-g094fc3778d6b #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: writeback wb_workfn (flush-7:5) RIP: 0010:mpage_map_one_extent fs/ext4/inode.c:2463 [inline] RIP: 0010:mpage_map_and_submit_extent fs/ext4/inode.c:2504 [inline] RIP: 0010:ext4_writepages+0x3b44/0x3c00 fs/ext4/inode.c:2872 Code: 00 74 08 48 89 df e8 fb c5 c9 ff 48 8b 3b 48 8b 74 24 28 48 8b 54 24 50 44 89 e1 45 89 f8 e8 93 de 07 00 eb 5d e8 9c 26 8c ff <0f> 0b e8 95 26 8c ff eb 3b e8 8e 26 8c ff eb 77 e8 87 26 8c ff 31 RSP: 0018:ffffc90000e570a0 EFLAGS: 00010293 RAX: ffffffff81de98b4 RBX: dffffc0000000000 RCX: ffff888115924f00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90000e57490 R08: ffffffff81de74b9 R09: ffffed1025f8cd6e R10: 0000000000000000 R11: dffffc0000000001 R12: ffffc90000e573b0 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555570f394e8 CR3: 000000010a90e000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: do_writepages+0x12e/0x270 mm/page-writeback.c:2380 __writeback_single_inode+0xd7/0xac0 fs/fs-writeback.c:1470 writeback_sb_inodes+0x99c/0x16b0 fs/fs-writeback.c:1733 wb_writeback+0x404/0xc60 fs/fs-writeback.c:1908 wb_do_writeback fs/fs-writeback.c:2053 [inline] wb_workfn+0x3d9/0x1110 fs/fs-writeback.c:2094 process_one_work+0x6dc/0xbd0 kernel/workqueue.c:2301 worker_thread+0xaea/0x1510 kernel/workqueue.c:2447 kthread+0x34b/0x3d0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 Modules linked in: ---[ end trace 6c7c31349df369fb ]--- RIP: 0010:mpage_map_one_extent fs/ext4/inode.c:2463 [inline] RIP: 0010:mpage_map_and_submit_extent fs/ext4/inode.c:2504 [inline] RIP: 0010:ext4_writepages+0x3b44/0x3c00 fs/ext4/inode.c:2872 Code: 00 74 08 48 89 df e8 fb c5 c9 ff 48 8b 3b 48 8b 74 24 28 48 8b 54 24 50 44 89 e1 45 89 f8 e8 93 de 07 00 eb 5d e8 9c 26 8c ff <0f> 0b e8 95 26 8c ff eb 3b e8 8e 26 8c ff eb 77 e8 87 26 8c ff 31 RSP: 0018:ffffc90000e570a0 EFLAGS: 00010293 RAX: ffffffff81de98b4 RBX: dffffc0000000000 RCX: ffff888115924f00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90000e57490 R08: ffffffff81de74b9 R09: ffffed1025f8cd6e R10: 0000000000000000 R11: dffffc0000000001 R12: ffffc90000e573b0 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f29c29c3338 CR3: 000000010a90e000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400