================================================================== 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 ffff88812e69d28c by task syz.4.817/3078 CPU: 1 PID: 3078 Comm: syz.4.817 Not tainted 5.10.238-syzkaller-1007487-g59e9a7228857 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 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_binsearch fs/ext4/extents.c:826 [inline] ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:945 ext4_ext_remove_space+0x306/0x4910 fs/ext4/extents.c:2826 ext4_punch_hole+0x6f8/0xad0 fs/ext4/inode.c:4217 ext4_fallocate+0x271/0x1a70 fs/ext4/extents.c:4756 vfs_fallocate+0x4b4/0x590 fs/open.c:310 madvise_remove mm/madvise.c:880 [inline] madvise_vma_behavior mm/madvise.c:904 [inline] madvise_walk_vmas mm/madvise.c:1131 [inline] do_madvise+0x12cf/0x1df0 mm/madvise.c:1308 __do_sys_madvise mm/madvise.c:1322 [inline] __se_sys_madvise mm/madvise.c:1320 [inline] __x64_sys_madvise+0xa9/0xc0 mm/madvise.c:1320 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f5246479929 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:00007f5245eea038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007f52466a0fa0 RCX: 00007f5246479929 RDX: 0000000000000009 RSI: 000000000060000b RDI: 0000200000000000 RBP: 00007f52464fbb39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f52466a0fa0 R15: 00007ffff70a6028 Allocated by task 3025: 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_slab_alloc+0xbd/0xf0 mm/kasan/common.c:463 kasan_slab_alloc include/linux/kasan.h:244 [inline] slab_post_alloc_hook+0x5d/0x2f0 mm/slab.h:583 slab_alloc_node mm/slub.c:2947 [inline] slab_alloc mm/slub.c:2955 [inline] kmem_cache_alloc+0x165/0x2e0 mm/slub.c:2960 kmem_cache_alloc_node include/linux/slab.h:423 [inline] __alloc_skb+0x9e/0x520 net/core/skbuff.c:200 alloc_skb include/linux/skbuff.h:1126 [inline] alloc_uevent_skb+0x85/0x240 lib/kobject_uevent.c:290 uevent_net_broadcast_tagged lib/kobject_uevent.c:351 [inline] kobject_uevent_net_broadcast+0x1a6/0x5a0 lib/kobject_uevent.c:412 kobject_uevent_env+0x52e/0x700 lib/kobject_uevent.c:608 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 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5628 netlink_unicast_kernel net/netlink/af_netlink.c:1307 [inline] netlink_unicast+0x87c/0xa40 net/netlink/af_netlink.c:1333 netlink_sendmsg+0x88d/0xb30 net/netlink/af_netlink.c:1901 sock_sendmsg_nosec net/socket.c:652 [inline] __sock_sendmsg net/socket.c:664 [inline] __sys_sendto+0x41d/0x580 net/socket.c:2006 __do_sys_sendto net/socket.c:2018 [inline] __se_sys_sendto net/socket.c:2014 [inline] __x64_sys_sendto+0xe5/0x100 net/socket.c:2014 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb Freed by task 3025: 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] kmem_cache_free+0x100/0x2d0 mm/slub.c:3219 kfree_skbmem+0x10c/0x180 net/core/skbuff.c:-1 __kfree_skb net/core/skbuff.c:695 [inline] consume_skb+0xb3/0x1f0 net/core/skbuff.c:851 netlink_broadcast_filtered+0x119a/0x1290 net/netlink/af_netlink.c:1517 netlink_broadcast+0x3a/0x50 net/netlink/af_netlink.c:1539 uevent_net_broadcast_tagged lib/kobject_uevent.c:372 [inline] kobject_uevent_net_broadcast+0x503/0x5a0 lib/kobject_uevent.c:412 kobject_uevent_env+0x52e/0x700 lib/kobject_uevent.c:608 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 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5628 netlink_unicast_kernel net/netlink/af_netlink.c:1307 [inline] netlink_unicast+0x87c/0xa40 net/netlink/af_netlink.c:1333 netlink_sendmsg+0x88d/0xb30 net/netlink/af_netlink.c:1901 sock_sendmsg_nosec net/socket.c:652 [inline] __sock_sendmsg net/socket.c:664 [inline] __sys_sendto+0x41d/0x580 net/socket.c:2006 __do_sys_sendto net/socket.c:2018 [inline] __se_sys_sendto net/socket.c:2014 [inline] __x64_sys_sendto+0xe5/0x100 net/socket.c:2014 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 ffff88812e69d280 which belongs to the cache skbuff_head_cache of size 248 The buggy address is located 12 bytes inside of 248-byte region [ffff88812e69d280, ffff88812e69d378) The buggy address belongs to the page: page:ffffea0004b9a740 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12e69d flags: 0x4000000000000200(slab) raw: 4000000000000200 dead000000000100 dead000000000122 ffff888107d94300 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 1257, ts 126899294175, free_ts 126822028416 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:5357 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+0x1af/0x2e0 mm/slub.c:2960 kmem_cache_alloc_node include/linux/slab.h:423 [inline] __alloc_skb+0x9e/0x520 net/core/skbuff.c:200 alloc_skb include/linux/skbuff.h:1126 [inline] nlmsg_new include/net/netlink.h:953 [inline] inet6_ifinfo_notify+0x6e/0x110 net/ipv6/addrconf.c:6052 addrconf_notify+0xb63/0xe90 net/ipv6/addrconf.c:3691 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0x90/0x100 kernel/notifier.c:410 call_netdevice_notifiers_info net/core/dev.c:2054 [inline] call_netdevice_notifiers_extack net/core/dev.c:2066 [inline] call_netdevice_notifiers net/core/dev.c:2080 [inline] __dev_notify_flags+0x28f/0x500 net/core/dev.c:-1 dev_change_flags+0xe8/0x1a0 net/core/dev.c:8610 do_setlink+0xbb4/0x3ab0 net/core/rtnetlink.c:2732 __rtnl_newlink net/core/rtnetlink.c:3410 [inline] rtnl_newlink+0x1292/0x1640 net/core/rtnetlink.c:3530 rtnetlink_rcv_msg+0x9db/0xb90 net/core/rtnetlink.c:5610 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 mm/page_alloc.c:3391 [inline] free_the_page mm/page_alloc.c:5416 [inline] __free_pages+0x14b/0x380 mm/page_alloc.c:5427 __free_slab+0xcf/0x190 mm/slub.c:1894 free_slab mm/slub.c:1909 [inline] discard_slab mm/slub.c:1915 [inline] unfreeze_partials+0x15f/0x190 mm/slub.c:2410 put_cpu_partial+0xc1/0x180 mm/slub.c:2446 __slab_free+0x2c9/0x3a0 mm/slub.c:3095 do_slab_free mm/slub.c:3191 [inline] ___cache_free+0x111/0x130 mm/slub.c:3210 qlink_free+0x50/0x90 mm/kasan/quarantine.c:157 qlist_free_all+0x5f/0xb0 mm/kasan/quarantine.c:176 kasan_quarantine_reduce+0x14a/0x160 mm/kasan/quarantine.c:283 ____kasan_kmalloc mm/kasan/common.c:475 [inline] __kasan_kmalloc+0x2f/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] call_modprobe kernel/kmod.c:79 [inline] __request_module+0x273/0x890 kernel/kmod.c:170 __rtnl_newlink net/core/rtnetlink.c:3433 [inline] rtnl_newlink+0x857/0x1640 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 Memory state around the buggy address: ffff88812e69d180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88812e69d200: fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc >ffff88812e69d280: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88812e69d300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc ffff88812e69d380: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ================================================================== ------------[ cut here ]------------ kernel BUG at fs/ext4/extents.c:3180! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 3078 Comm: syz.4.817 Tainted: G B 5.10.238-syzkaller-1007487-g59e9a7228857 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:ext4_split_extent_at+0xe6e/0xe90 fs/ext4/extents.c:3180 Code: 48 89 df 48 89 74 24 68 e8 2f 8c d3 ff 48 8b 74 24 68 e9 5a fb ff ff e8 00 9c 99 ff 0f 0b e8 f9 9b 99 ff 0f 0b e8 f2 9b 99 ff <0f> 0b e8 eb 9b 99 ff 0f 0b e8 e4 9b 99 ff 0f 0b e8 dd 9b 99 ff 0f RSP: 0018:ffffc90003fc74a0 EFLAGS: 00010293 RAX: ffffffff81c9f81e RBX: 0000000000000000 RCX: ffff888135d34f00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000002c RBP: ffffc90003fc7610 R08: 0000000000000000 R09: 0000000050000028 R10: fffffbfff0d8e448 R11: 1ffffffff0d8e448 R12: 0000000000000000 R13: 0000000000000000 R14: 1ffff11025cd3a4f R15: 0000000000000000 FS: 00007f5245eea6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000001007f CR3: 000000012bb3e000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ext4_force_split_extent_at fs/ext4/extents.c:318 [inline] ext4_ext_remove_space+0x677/0x4910 fs/ext4/extents.c:2873 ext4_punch_hole+0x6f8/0xad0 fs/ext4/inode.c:4217 ext4_fallocate+0x271/0x1a70 fs/ext4/extents.c:4756 vfs_fallocate+0x4b4/0x590 fs/open.c:310 madvise_remove mm/madvise.c:880 [inline] madvise_vma_behavior mm/madvise.c:904 [inline] madvise_walk_vmas mm/madvise.c:1131 [inline] do_madvise+0x12cf/0x1df0 mm/madvise.c:1308 __do_sys_madvise mm/madvise.c:1322 [inline] __se_sys_madvise mm/madvise.c:1320 [inline] __x64_sys_madvise+0xa9/0xc0 mm/madvise.c:1320 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f5246479929 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:00007f5245eea038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007f52466a0fa0 RCX: 00007f5246479929 RDX: 0000000000000009 RSI: 000000000060000b RDI: 0000200000000000 RBP: 00007f52464fbb39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f52466a0fa0 R15: 00007ffff70a6028 Modules linked in: ---[ end trace 0c91e139ff04c8d8 ]--- RIP: 0010:ext4_split_extent_at+0xe6e/0xe90 fs/ext4/extents.c:3180 Code: 48 89 df 48 89 74 24 68 e8 2f 8c d3 ff 48 8b 74 24 68 e9 5a fb ff ff e8 00 9c 99 ff 0f 0b e8 f9 9b 99 ff 0f 0b e8 f2 9b 99 ff <0f> 0b e8 eb 9b 99 ff 0f 0b e8 e4 9b 99 ff 0f 0b e8 dd 9b 99 ff 0f RSP: 0018:ffffc90003fc74a0 EFLAGS: 00010293 RAX: ffffffff81c9f81e RBX: 0000000000000000 RCX: ffff888135d34f00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000002c RBP: ffffc90003fc7610 R08: 0000000000000000 R09: 0000000050000028 R10: fffffbfff0d8e448 R11: 1ffffffff0d8e448 R12: 0000000000000000 R13: 0000000000000000 R14: 1ffff11025cd3a4f R15: 0000000000000000 FS: 00007f5245eea6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb5384aebac CR3: 000000012bb3e000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400