================================================================== 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 ffff888127355018 by task kworker/u4:5/1139 CPU: 0 PID: 1139 Comm: kworker/u4:5 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-7:2) 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 1320: 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 skb_clone+0x1cf/0x360 net/core/skbuff.c:1547 netlink_trim+0x15a/0x230 net/netlink/af_netlink.c:1296 netlink_broadcast_filtered+0x78/0x1230 net/netlink/af_netlink.c:1515 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 rtnetlink_send+0x62/0x70 net/core/rtnetlink.c:743 tcf_del_notify net/sched/act_api.c:1457 [inline] tca_action_gd+0xec1/0x19c0 net/sched/act_api.c:1500 tc_ctl_action+0x35f/0xb10 net/sched/act_api.c:-1 rtnetlink_rcv_msg+0x9e4/0xb90 net/core/rtnetlink.c:5650 netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2511 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5668 netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline] netlink_unicast+0x876/0xa40 net/netlink/af_netlink.c:1348 netlink_sendmsg+0x86a/0xb70 net/netlink/af_netlink.c:1922 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] ____sys_sendmsg+0x5a2/0x8c0 net/socket.c:2436 ___sys_sendmsg+0x1f0/0x260 net/socket.c:2490 __sys_sendmsg net/socket.c:2519 [inline] __do_sys_sendmsg net/socket.c:2528 [inline] __se_sys_sendmsg net/socket.c:2526 [inline] __x64_sys_sendmsg+0x1e2/0x2a0 net/socket.c:2526 x64_sys_call+0x4b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:47 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 1320: 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 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 rtnetlink_send+0x62/0x70 net/core/rtnetlink.c:743 tcf_del_notify net/sched/act_api.c:1457 [inline] tca_action_gd+0xec1/0x19c0 net/sched/act_api.c:1500 tc_ctl_action+0x35f/0xb10 net/sched/act_api.c:-1 rtnetlink_rcv_msg+0x9e4/0xb90 net/core/rtnetlink.c:5650 netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2511 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5668 netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline] netlink_unicast+0x876/0xa40 net/netlink/af_netlink.c:1348 netlink_sendmsg+0x86a/0xb70 net/netlink/af_netlink.c:1922 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] ____sys_sendmsg+0x5a2/0x8c0 net/socket.c:2436 ___sys_sendmsg+0x1f0/0x260 net/socket.c:2490 __sys_sendmsg net/socket.c:2519 [inline] __do_sys_sendmsg net/socket.c:2528 [inline] __se_sys_sendmsg net/socket.c:2526 [inline] __x64_sys_sendmsg+0x1e2/0x2a0 net/socket.c:2526 x64_sys_call+0x4b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:47 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 The buggy address belongs to the object at ffff888127355000 which belongs to the cache skbuff_head_cache of size 248 The buggy address is located 24 bytes inside of 248-byte region [ffff888127355000, ffff8881273550f8) The buggy address belongs to the page: page:ffffea00049cd540 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x127355 flags: 0x4000000000000200(slab|zone=1) raw: 4000000000000200 dead000000000100 dead000000000122 ffff8881081abe00 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 282, ts 28322690604, free_ts 0 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_alloc_node include/linux/slab.h:489 [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] inet6_netconf_notify_devconf+0xd6/0x190 net/ipv6/addrconf.c:583 __addrconf_sysctl_register+0x365/0x3d0 net/ipv6/addrconf.c:7160 addrconf_sysctl_register+0x147/0x1a0 net/ipv6/addrconf.c:7197 ipv6_add_dev+0xc03/0x1150 net/ipv6/addrconf.c:454 addrconf_notify+0x582/0xde0 net/ipv6/addrconf.c:3597 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0x90/0x100 kernel/notifier.c:391 call_netdevice_notifiers_info net/core/dev.c:2057 [inline] call_netdevice_notifiers_extack net/core/dev.c:2069 [inline] call_netdevice_notifiers+0x111/0x190 net/core/dev.c:2083 page_owner free stack trace missing Memory state around the buggy address: ffff888127354f00: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff888127354f80: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc >ffff888127355000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888127355080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc ffff888127355100: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ================================================================== EXT4-fs error (device loop2): ext4_ext_split:1074: inode #15: comm kworker/u4:5: p_ext > EXT_MAX_EXTENT! EXT4-fs (loop2): Delayed block allocation failed for inode 15 at logical offset 0 with max blocks 1 with error 117 EXT4-fs (loop2): This should not happen!! Data will be lost