ext4 filesystem being mounted at /0/file0aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa supports timestamps until 2038-01-19 (0x7fffffff) ================================================================== 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 ffff88813020020c by task syz.7.218/1368 CPU: 0 PID: 1368 Comm: syz.7.218 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 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_remove_space+0x2bc/0x4180 fs/ext4/extents.c:2834 ext4_punch_hole+0x77c/0xbd0 fs/ext4/inode.c:4137 ext4_fallocate+0x2b6/0x1de0 fs/ext4/extents.c:4765 vfs_fallocate+0x4b4/0x590 fs/open.c:309 madvise_remove mm/madvise.c:964 [inline] madvise_vma_behavior mm/madvise.c:988 [inline] madvise_walk_vmas mm/madvise.c:1218 [inline] do_madvise+0x12c8/0x2200 mm/madvise.c:1396 __do_sys_madvise mm/madvise.c:1409 [inline] __se_sys_madvise mm/madvise.c:1407 [inline] __x64_sys_madvise+0xa9/0xc0 mm/madvise.c:1407 x64_sys_call+0x89b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:29 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 RIP: 0033:0x7f4eaad6e6c9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 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:00007f4eaabde038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007f4eaafc4fa0 RCX: 00007f4eaad6e6c9 RDX: 0000000000000009 RSI: 000000000060000b RDI: 0000200000000000 RBP: 00007f4eaadf0f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4eaafc5038 R14: 00007f4eaafc4fa0 R15: 00007ffc5944a8b8 Allocated by task 718: 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:3245 [inline] slab_alloc mm/slub.c:3255 [inline] kmem_cache_alloc+0xf7/0x260 mm/slub.c:3260 kmem_cache_alloc_node include/linux/slab.h:492 [inline] __alloc_skb+0xe0/0x740 net/core/skbuff.c:416 alloc_skb include/linux/skbuff.h:1183 [inline] nlmsg_new include/net/netlink.h:953 [inline] __neigh_notify+0x84/0x130 net/core/neighbour.c:3379 neigh_cleanup_and_release+0x2c/0x1a0 net/core/neighbour.c:101 neigh_del net/core/neighbour.c:197 [inline] neigh_remove_one+0x379/0x400 net/core/neighbour.c:218 neigh_forced_gc net/core/neighbour.c:251 [inline] neigh_alloc net/core/neighbour.c:429 [inline] ___neigh_create+0x492/0x1be0 net/core/neighbour.c:591 __neigh_create+0x31/0x40 net/core/neighbour.c:679 ip6_finish_output2+0xab3/0x1760 net/ipv6/ip6_output.c:127 __ip6_finish_output+0x61e/0x7d0 net/ipv6/ip6_output.c:201 ip6_finish_output+0x31/0x240 net/ipv6/ip6_output.c:211 NF_HOOK_COND include/linux/netfilter.h:294 [inline] ip6_output+0x1d1/0x3b0 net/ipv6/ip6_output.c:234 dst_output include/net/dst.h:453 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] ndisc_send_skb+0x797/0xc70 net/ipv6/ndisc.c:513 ndisc_send_ns+0x842/0xaf0 net/ipv6/ndisc.c:655 addrconf_dad_work+0xa2b/0x1540 net/ipv6/addrconf.c:4222 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 Freed by task 718: 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:1728 [inline] slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1754 slab_free mm/slub.c:3526 [inline] kmem_cache_free+0x100/0x320 mm/slub.c:3544 kfree_skbmem+0x10c/0x180 net/core/skbuff.c:-1 __kfree_skb net/core/skbuff.c:758 [inline] consume_skb+0xb3/0x1f0 net/core/skbuff.c:930 netlink_broadcast_filtered+0x113a/0x1230 net/netlink/af_netlink.c:1538 netlink_broadcast net/netlink/af_netlink.c:1560 [inline] nlmsg_multicast include/net/netlink.h:1033 [inline] nlmsg_notify+0xed/0x1b0 net/netlink/af_netlink.c:2554 rtnl_notify+0x9a/0xc0 net/core/rtnetlink.c:759 __neigh_notify+0xd3/0x130 net/core/neighbour.c:3390 neigh_cleanup_and_release+0x2c/0x1a0 net/core/neighbour.c:101 neigh_del net/core/neighbour.c:197 [inline] neigh_remove_one+0x379/0x400 net/core/neighbour.c:218 neigh_forced_gc net/core/neighbour.c:251 [inline] neigh_alloc net/core/neighbour.c:429 [inline] ___neigh_create+0x492/0x1be0 net/core/neighbour.c:591 __neigh_create+0x31/0x40 net/core/neighbour.c:679 ip6_finish_output2+0xab3/0x1760 net/ipv6/ip6_output.c:127 __ip6_finish_output+0x61e/0x7d0 net/ipv6/ip6_output.c:201 ip6_finish_output+0x31/0x240 net/ipv6/ip6_output.c:211 NF_HOOK_COND include/linux/netfilter.h:294 [inline] ip6_output+0x1d1/0x3b0 net/ipv6/ip6_output.c:234 dst_output include/net/dst.h:453 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] ndisc_send_skb+0x797/0xc70 net/ipv6/ndisc.c:513 ndisc_send_ns+0x842/0xaf0 net/ipv6/ndisc.c:655 addrconf_dad_work+0xa2b/0x1540 net/ipv6/addrconf.c:4222 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 The buggy address belongs to the object at ffff888130200140 which belongs to the cache skbuff_head_cache of size 248 The buggy address is located 204 bytes inside of 248-byte region [ffff888130200140, ffff888130200238) The buggy address belongs to the page: page:ffffea0004c08000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x130200 flags: 0x4000000000000200(slab|zone=1) raw: 4000000000000200 0000000000000000 dead000000000122 ffff8881081aac00 raw: 0000000000000000 00000000000c000c 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 718, ts 129371527502, free_ts 129350531332 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:5808 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1937 [inline] new_slab+0xa1/0x4d0 mm/slub.c:2000 ___slab_alloc+0x381/0x810 mm/slub.c:3033 __slab_alloc+0x49/0x90 mm/slub.c:3120 slab_alloc_node mm/slub.c:3211 [inline] slab_alloc mm/slub.c:3255 [inline] kmem_cache_alloc+0x138/0x260 mm/slub.c:3260 kmem_cache_alloc_node include/linux/slab.h:492 [inline] __alloc_skb+0xe0/0x740 net/core/skbuff.c:416 alloc_skb include/linux/skbuff.h:1183 [inline] nlmsg_new include/net/netlink.h:953 [inline] __neigh_notify+0x84/0x130 net/core/neighbour.c:3379 neigh_cleanup_and_release+0x2c/0x1a0 net/core/neighbour.c:101 neigh_del net/core/neighbour.c:197 [inline] neigh_remove_one+0x379/0x400 net/core/neighbour.c:218 neigh_forced_gc net/core/neighbour.c:251 [inline] neigh_alloc net/core/neighbour.c:429 [inline] ___neigh_create+0x492/0x1be0 net/core/neighbour.c:591 __neigh_create+0x31/0x40 net/core/neighbour.c:679 ip6_finish_output2+0xab3/0x1760 net/ipv6/ip6_output.c:127 __ip6_finish_output+0x61e/0x7d0 net/ipv6/ip6_output.c:201 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_list+0x134/0x9d0 mm/page_alloc.c:3671 release_pages+0xfda/0x1030 mm/swap.c:1014 __pagevec_release+0x71/0xe0 mm/swap.c:1034 pagevec_release include/linux/pagevec.h:81 [inline] truncate_inode_pages_range+0x2f7/0xd60 mm/truncate.c:332 truncate_inode_pages+0x24/0x30 mm/truncate.c:428 kill_bdev block/bdev.c:77 [inline] blkdev_flush_mapping+0x182/0x340 block/bdev.c:659 blkdev_put_whole block/bdev.c:690 [inline] blkdev_put+0x47d/0x770 block/bdev.c:957 blkdev_close+0x77/0xa0 block/fops.c:478 __fput+0x20b/0x8b0 fs/file_table.c:311 ____fput+0x15/0x20 fs/file_table.c:339 task_work_run+0x127/0x190 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop+0xd0/0xe0 kernel/entry/common.c:181 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 Memory state around the buggy address: ffff888130200100: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ffff888130200180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888130200200: fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc ^ ffff888130200280: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888130200300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc ================================================================== EXT4-fs error (device loop7): ext4_ext_split:1074: inode #12: comm syz.7.218: p_ext > EXT_MAX_EXTENT! EXT4-fs error (device loop7): __ext4_get_inode_loc:4358: comm syz.7.218: Invalid inode table block 19032600419 in block_group 0 EXT4-fs error (device loop7) in ext4_reserve_inode_write:5873: Corrupt filesystem EXT4-fs error (device loop7): ext4_punch_hole:4150: inode #12: comm syz.7.218: mark_inode_dirty error