EXT4-fs error (device loop3): ext4_ext_map_blocks:4177: inode #19: comm kworker/u4:1: bad extent address lblock: 0, depth: 1 pblock 0 EXT4-fs (loop3): Delayed block allocation failed for inode 19 at logical offset 0 with max blocks 16 with error 117 EXT4-fs (loop3): This should not happen!! Data will be lost ================================================================== BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:826 [inline] BUG: KASAN: use-after-free in ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:945 Read of size 4 at addr ffff88812041c000 by task kworker/u4:1/9 CPU: 1 PID: 9 Comm: kworker/u4:1 Not tainted 5.10.237-syzkaller-1007474-gcf6ed0f1511d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: writeback wb_workfn (flush-7:1) 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_binsearch fs/ext4/extents.c:826 [inline] ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:945 ext4_ext_map_blocks+0x1de/0x5d40 fs/ext4/extents.c:4159 ext4_map_blocks+0x978/0x1bc0 fs/ext4/inode.c:674 mpage_map_one_extent fs/ext4/inode.c:2452 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2505 [inline] ext4_writepages+0x11d5/0x2e00 fs/ext4/inode.c:2873 do_writepages+0x12a/0x270 mm/page-writeback.c:2380 __writeback_single_inode+0xd5/0xa20 fs/fs-writeback.c:1470 writeback_sb_inodes+0x860/0x1400 fs/fs-writeback.c:1733 wb_writeback+0x3e3/0xb90 fs/fs-writeback.c:1908 wb_do_writeback fs/fs-writeback.c:2053 [inline] wb_workfn+0x38f/0xe20 fs/fs-writeback.c:2094 process_one_work+0x6e1/0xba0 kernel/workqueue.c:2301 worker_thread+0xa6a/0x13b0 kernel/workqueue.c:2447 kthread+0x346/0x3d0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 Allocated by task 355: 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:430 [inline] ____kasan_kmalloc mm/kasan/common.c:509 [inline] __kasan_kmalloc+0xda/0x110 mm/kasan/common.c:518 kasan_kmalloc include/linux/kasan.h:254 [inline] kmem_cache_alloc_trace+0x184/0x2e0 mm/slub.c:2974 kmalloc include/linux/slab.h:552 [inline] kzalloc include/linux/slab.h:664 [inline] uevent_show+0x160/0x330 drivers/base/core.c:2295 dev_attr_show+0x56/0xd0 drivers/base/core.c:2002 sysfs_kf_seq_show+0x266/0x3d0 fs/sysfs/file.c:61 kernfs_seq_show+0x119/0x160 fs/kernfs/file.c:168 seq_read_iter+0x490/0xd30 fs/seq_file.c:230 kernfs_fop_read_iter+0x147/0x470 fs/kernfs/file.c:241 call_read_iter include/linux/fs.h:2052 [inline] new_sync_read fs/read_write.c:415 [inline] vfs_read+0x874/0xa10 fs/read_write.c:496 ksys_read+0x140/0x240 fs/read_write.c:634 __do_sys_read fs/read_write.c:644 [inline] __se_sys_read fs/read_write.c:642 [inline] __x64_sys_read+0x7b/0x90 fs/read_write.c:642 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb Freed by task 355: 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:362 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370 kasan_slab_free include/linux/kasan.h:220 [inline] slab_free_hook mm/slub.c:1595 [inline] slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1621 slab_free mm/slub.c:3203 [inline] kfree+0xc0/0x270 mm/slub.c:4191 uevent_show+0x1fb/0x330 drivers/base/core.c:2311 dev_attr_show+0x56/0xd0 drivers/base/core.c:2002 sysfs_kf_seq_show+0x266/0x3d0 fs/sysfs/file.c:61 kernfs_seq_show+0x119/0x160 fs/kernfs/file.c:168 seq_read_iter+0x490/0xd30 fs/seq_file.c:230 kernfs_fop_read_iter+0x147/0x470 fs/kernfs/file.c:241 call_read_iter include/linux/fs.h:2052 [inline] new_sync_read fs/read_write.c:415 [inline] vfs_read+0x874/0xa10 fs/read_write.c:496 ksys_read+0x140/0x240 fs/read_write.c:634 __do_sys_read fs/read_write.c:644 [inline] __se_sys_read fs/read_write.c:642 [inline] __x64_sys_read+0x7b/0x90 fs/read_write.c:642 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb The buggy address belongs to the object at ffff88812041c000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 0 bytes inside of 4096-byte region [ffff88812041c000, ffff88812041d000) The buggy address belongs to the page: page:ffffea0004810600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x120418 head:ffffea0004810600 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head) raw: 4000000000010200 dead000000000100 dead000000000122 ffff888100042c00 raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 284, ts 25968242006, free_ts 0 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:5349 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1808 [inline] new_slab+0x84/0x3f0 mm/slub.c:1869 new_slab_objects mm/slub.c:2627 [inline] ___slab_alloc+0x2a6/0x450 mm/slub.c:2791 __slab_alloc+0x63/0xa0 mm/slub.c:2831 slab_alloc_node mm/slub.c:2913 [inline] slab_alloc mm/slub.c:2955 [inline] kmem_cache_alloc_trace+0x1b3/0x2e0 mm/slub.c:2972 kmalloc include/linux/slab.h:552 [inline] kzalloc include/linux/slab.h:664 [inline] kobject_uevent_env+0x272/0x700 lib/kobject_uevent.c:539 kobject_uevent+0x1d/0x30 lib/kobject_uevent.c:657 netdev_queue_add_kobject net/core/net-sysfs.c:1660 [inline] netdev_queue_update_kobjects+0x1a7/0x390 net/core/net-sysfs.c:1694 register_queue_kobjects net/core/net-sysfs.c:1755 [inline] netdev_register_kobject+0x26e/0x320 net/core/net-sysfs.c:2001 register_netdevice+0xddd/0x13c0 net/core/dev.c:10056 wg_newlink+0x4f1/0x7a0 drivers/net/wireguard/device.c:355 __rtnl_newlink net/core/rtnetlink.c:3482 [inline] rtnl_newlink+0x11bd/0x1640 net/core/rtnetlink.c:3530 rtnetlink_rcv_msg+0x9db/0xb90 net/core/rtnetlink.c:5610 netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2485 page_owner free stack trace missing Memory state around the buggy address: ffff88812041bf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88812041bf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88812041c000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88812041c080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88812041c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ------------[ cut here ]------------ kernel BUG at fs/ext4/inode.c:2464! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 9 Comm: kworker/u4:1 Tainted: G B 5.10.237-syzkaller-1007474-gcf6ed0f1511d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: writeback wb_workfn (flush-7:1) RIP: 0010:mpage_map_one_extent fs/ext4/inode.c:2464 [inline] RIP: 0010:mpage_map_and_submit_extent fs/ext4/inode.c:2505 [inline] RIP: 0010:ext4_writepages+0x2d49/0x2e00 fs/ext4/inode.c:2873 Code: 08 48 89 df e8 48 27 ce ff 48 8b 3b 48 8b 74 24 40 48 8b 54 24 28 48 8b 4c 24 20 45 89 f0 e8 7e 41 07 00 eb 56 e8 67 37 94 ff <0f> 0b e8 60 37 94 ff eb 2f e8 59 37 94 ff eb 64 e8 52 37 94 ff 31 RSP: 0018:ffffc90000097180 EFLAGS: 00010293 RAX: ffffffff81cf5b09 RBX: 0000000000000000 RCX: ffff88810024a780 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900000974f0 R08: dffffc0000000000 R09: ffffed1024bb3d6e R10: ffffed1024bb3d6e R11: 1ffff11024bb3d6d R12: dffffc0000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 000000000000042b FS: 0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055557cdde858 CR3: 000000010cb70000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: do_writepages+0x12a/0x270 mm/page-writeback.c:2380 __writeback_single_inode+0xd5/0xa20 fs/fs-writeback.c:1470 writeback_sb_inodes+0x860/0x1400 fs/fs-writeback.c:1733 wb_writeback+0x3e3/0xb90 fs/fs-writeback.c:1908 wb_do_writeback fs/fs-writeback.c:2053 [inline] wb_workfn+0x38f/0xe20 fs/fs-writeback.c:2094 process_one_work+0x6e1/0xba0 kernel/workqueue.c:2301 worker_thread+0xa6a/0x13b0 kernel/workqueue.c:2447 kthread+0x346/0x3d0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 Modules linked in: ---[ end trace 57ecc794f5b99c07 ]--- RIP: 0010:mpage_map_one_extent fs/ext4/inode.c:2464 [inline] RIP: 0010:mpage_map_and_submit_extent fs/ext4/inode.c:2505 [inline] RIP: 0010:ext4_writepages+0x2d49/0x2e00 fs/ext4/inode.c:2873 Code: 08 48 89 df e8 48 27 ce ff 48 8b 3b 48 8b 74 24 40 48 8b 54 24 28 48 8b 4c 24 20 45 89 f0 e8 7e 41 07 00 eb 56 e8 67 37 94 ff <0f> 0b e8 60 37 94 ff eb 2f e8 59 37 94 ff eb 64 e8 52 37 94 ff 31 RSP: 0018:ffffc90000097180 EFLAGS: 00010293 RAX: ffffffff81cf5b09 RBX: 0000000000000000 RCX: ffff88810024a780 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900000974f0 R08: dffffc0000000000 R09: ffffed1024bb3d6e R10: ffffed1024bb3d6e R11: 1ffff11024bb3d6d R12: dffffc0000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 000000000000042b FS: 0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055557cdde858 CR3: 000000010bd35000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400