================================================================== BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:827 [inline] BUG: KASAN: use-after-free in ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:946 Read of size 4 at addr ffff888134617018 by task kworker/u4:4/361 CPU: 1 PID: 361 Comm: kworker/u4:4 Not tainted 5.15.189-syzkaller-00079-ga71626bd56a5 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: writeback wb_workfn (flush-7:6) Call Trace: __dump_stack+0x21/0x30 lib/dump_stack.c:88 dump_stack_lvl+0xee/0x150 lib/dump_stack.c:106 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:427 [inline] kasan_report+0xf1/0x140 mm/kasan/report.c:444 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308 ext4_ext_binsearch fs/ext4/extents.c:827 [inline] ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:946 ext4_ext_map_blocks+0x1de/0x6280 fs/ext4/extents.c:4166 ext4_map_blocks+0x97b/0x1b20 fs/ext4/inode.c:674 mpage_map_one_extent fs/ext4/inode.c:2421 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2474 [inline] ext4_writepages+0x11e7/0x2f90 fs/ext4/inode.c:2842 do_writepages+0x48a/0x6c0 mm/page-writeback.c:2388 __writeback_single_inode+0xd5/0x9c0 fs/fs-writeback.c:1647 writeback_sb_inodes+0x9c0/0x1590 fs/fs-writeback.c:1930 wb_writeback+0x3f1/0x980 fs/fs-writeback.c:2106 wb_do_writeback fs/fs-writeback.c:2253 [inline] wb_workfn+0x38f/0xe20 fs/fs-writeback.c:2294 process_one_work+0x6be/0xba0 kernel/workqueue.c:2325 worker_thread+0xa59/0x1200 kernel/workqueue.c:2472 kthread+0x411/0x500 kernel/kthread.c:337 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Allocated by task 2819: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:433 [inline] __kasan_slab_alloc+0xbd/0xf0 mm/kasan/common.c:466 kasan_slab_alloc include/linux/kasan.h:217 [inline] slab_post_alloc_hook+0x4f/0x2b0 mm/slab.h:550 slab_alloc_node mm/slub.c:3240 [inline] slab_alloc mm/slub.c:3250 [inline] kmem_cache_alloc+0xf7/0x260 mm/slub.c:3255 kmem_cache_zalloc include/linux/slab.h:737 [inline] copy_signal+0x54/0x600 kernel/fork.c:1710 copy_process+0x1130/0x3210 kernel/fork.c:2345 kernel_clone+0x23f/0x940 kernel/fork.c:2737 __do_sys_clone kernel/fork.c:2863 [inline] __se_sys_clone kernel/fork.c:2847 [inline] __x64_sys_clone+0x176/0x1d0 kernel/fork.c:2847 x64_sys_call+0x41f/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:57 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 Freed by task 13: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4a/0x70 mm/kasan/common.c:45 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:365 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:373 kasan_slab_free include/linux/kasan.h:193 [inline] slab_free_hook mm/slub.c:1723 [inline] slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1749 slab_free mm/slub.c:3521 [inline] kmem_cache_free+0x100/0x320 mm/slub.c:3539 free_signal_struct kernel/fork.c:785 [inline] put_signal_struct kernel/fork.c:791 [inline] __put_task_struct+0x24e/0x3e0 kernel/fork.c:806 put_task_struct include/linux/sched/task.h:141 [inline] delayed_put_task_struct+0x6c/0x1a0 kernel/exit.c:222 rcu_do_batch+0x51d/0xba0 kernel/rcu/tree.c:2523 rcu_core+0x5e4/0xf80 kernel/rcu/tree.c:2763 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2776 handle_softirqs+0x250/0x560 kernel/softirq.c:583 run_ksoftirqd+0x28/0x40 kernel/softirq.c:959 smpboot_thread_fn+0x45a/0x8c0 kernel/smpboot.c:164 kthread+0x411/0x500 kernel/kthread.c:337 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 The buggy address belongs to the object at ffff888134616d00 which belongs to the cache signal_cache of size 1120 The buggy address is located 792 bytes inside of 1120-byte region [ffff888134616d00, ffff888134617160) The buggy address belongs to the page: page:ffffea0004d18500 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888134615e00 pfn:0x134614 head:ffffea0004d18500 order:2 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head|zone=1) raw: 4000000000010200 0000000000000000 0000000100000001 ffff888100186300 raw: ffff888134615e00 00000000800c000b 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 540, ts 67961951281, free_ts 67612915796 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2605 prep_new_page+0x1c/0x110 mm/page_alloc.c:2611 get_page_from_freelist+0x2cc5/0x2d50 mm/page_alloc.c:4485 __alloc_pages+0x18f/0x440 mm/page_alloc.c:5795 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1932 [inline] new_slab+0xa1/0x4d0 mm/slub.c:1995 ___slab_alloc+0x381/0x810 mm/slub.c:3028 __slab_alloc+0x49/0x90 mm/slub.c:3115 slab_alloc_node mm/slub.c:3206 [inline] slab_alloc mm/slub.c:3250 [inline] kmem_cache_alloc+0x138/0x260 mm/slub.c:3255 kmem_cache_zalloc include/linux/slab.h:737 [inline] copy_signal+0x54/0x600 kernel/fork.c:1710 copy_process+0x1130/0x3210 kernel/fork.c:2345 kernel_clone+0x23f/0x940 kernel/fork.c:2737 __do_sys_clone kernel/fork.c:2863 [inline] __se_sys_clone kernel/fork.c:2847 [inline] __x64_sys_clone+0x176/0x1d0 kernel/fork.c:2847 x64_sys_call+0x41f/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:57 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 page last free stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] free_pages_prepare mm/page_alloc.c:1472 [inline] free_pcp_prepare mm/page_alloc.c:1544 [inline] free_unref_page_prepare+0x542/0x550 mm/page_alloc.c:3534 free_unref_page+0xa2/0x550 mm/page_alloc.c:3616 free_the_page mm/page_alloc.c:805 [inline] __free_pages+0x6c/0x100 mm/page_alloc.c:5871 pcpu_free_pages mm/percpu-vm.c:65 [inline] pcpu_depopulate_chunk+0x481/0x5a0 mm/percpu-vm.c:330 pcpu_reclaim_populated mm/percpu.c:2195 [inline] pcpu_balance_workfn+0x2a7/0x1150 mm/percpu.c:2247 process_one_work+0x6be/0xba0 kernel/workqueue.c:2325 worker_thread+0xa59/0x1200 kernel/workqueue.c:2472 kthread+0x411/0x500 kernel/kthread.c:337 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Memory state around the buggy address: ffff888134616f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888134616f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888134617000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888134617080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888134617100: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ================================================================== EXT4-fs error (device loop6): ext4_ext_split:1074: inode #15: comm kworker/u4:4: p_ext > EXT_MAX_EXTENT! EXT4-fs (loop6): Delayed block allocation failed for inode 15 at logical offset 0 with max blocks 1 with error 117 EXT4-fs (loop6): This should not happen!! Data will be lost