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006d021491bc7-6961e459310mr2814533eaf.28.1777016213844; Fri, 24 Apr 2026 00:36:53 -0700 (PDT) Date: Fri, 24 Apr 2026 00:36:53 -0700 In-Reply-To: <20260423212827.1177552-1-michael.bommarito@gmail.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69eb1d95.a00a0220.17a17.0055.GAE@google.com> Subject: [syzbot ci] Re: netlink: clean up failed initial dump-start state From: syzbot ci To: davem@davemloft.net, edumazet@google.com, horms@kernel.org, kees@kernel.org, kuba@kernel.org, kuniyu@google.com, linux-kernel@vger.kernel.org, michael.bommarito@gmail.com, netdev@vger.kernel.org, pabeni@redhat.com, yangfeng@kylinos.cn Cc: syzbot@lists.linux.dev, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot ci has tested the following series [v2] netlink: clean up failed initial dump-start state https://lore.kernel.org/all/20260423212827.1177552-1-michael.bommarito@gmail.com * [PATCH net-next v2] netlink: clean up failed initial dump-start state and found the following issues: * KASAN: slab-use-after-free Read in inet_diag_dump_done * KASAN: slab-use-after-free Read in netlink_dump_done * KASAN: slab-use-after-free Read in netlink_rcv_skb * KASAN: slab-use-after-free Read in rdma_nl_rcv * KASAN: slab-use-after-free Write in genl_done Full report is available here: https://ci.syzbot.org/series/d76773fc-9b84-4669-b27e-791385b0b902 *** KASAN: slab-use-after-free Read in inet_diag_dump_done tree: torvalds URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux base: 0b5e8d7999076ac3c490fc18376a404e2626abff arch: amd64 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 config: https://ci.syzbot.org/builds/cb46a152-33c1-4b5e-bb75-bab2ecb45113/config syz repro: https://ci.syzbot.org/findings/546e718b-5aa2-4705-85d2-51b88eb73b34/syz_repro ================================================================== BUG: KASAN: slab-use-after-free in inet_diag_dump_done+0x54/0x90 net/ipv4/inet_diag.c:893 Read of size 8 at addr ffff888110c9a1a0 by task syz.1.18/6001 CPU: 0 UID: 0 PID: 6001 Comm: syz.1.18 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 inet_diag_dump_done+0x54/0x90 net/ipv4/inet_diag.c:893 netlink_dump_cleanup+0x99/0x120 net/netlink/af_netlink.c:2259 netlink_dump+0xbe9/0xf40 net/netlink/af_netlink.c:2385 __netlink_dump_start+0x5cb/0x7e0 net/netlink/af_netlink.c:2455 netlink_dump_start include/linux/netlink.h:341 [inline] inet_diag_handler_cmd+0x1e0/0x2c0 net/ipv4/inet_diag.c:978 sock_diag_rcv_msg+0x4cc/0x600 net/core/sock_diag.c:-1 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2565 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1890 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe80d39c819 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe80e220028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fe80d616090 RCX: 00007fe80d39c819 RDX: 0000000000000000 RSI: 0000200000000200 RDI: 0000000000000003 RBP: 00007fe80d432c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe80d616128 R14: 00007fe80d616090 R15: 00007ffc5edf12b8 Allocated by task 6001: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5380 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] __inet_diag_dump_start+0x8b/0xbf0 net/ipv4/inet_diag.c:848 __netlink_dump_start+0x469/0x7e0 net/netlink/af_netlink.c:2446 netlink_dump_start include/linux/netlink.h:341 [inline] inet_diag_handler_cmd+0x1e0/0x2c0 net/ipv4/inet_diag.c:978 sock_diag_rcv_msg+0x4cc/0x600 net/core/sock_diag.c:-1 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2565 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1890 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 5995: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2685 [inline] slab_free mm/slub.c:6165 [inline] kfree+0x1c5/0x640 mm/slub.c:6483 inet_diag_dump_done+0x73/0x90 net/ipv4/inet_diag.c:894 netlink_dump_cleanup+0x99/0x120 net/netlink/af_netlink.c:2259 netlink_dump+0xbe9/0xf40 net/netlink/af_netlink.c:2385 netlink_recvmsg+0x690/0xa50 net/netlink/af_netlink.c:1972 sock_recvmsg_nosec net/socket.c:1078 [inline] sock_recvmsg+0x172/0x1b0 net/socket.c:1100 ____sys_recvmsg+0x1e6/0x4a0 net/socket.c:2812 ___sys_recvmsg+0x215/0x590 net/socket.c:2854 __sys_recvmsg net/socket.c:2887 [inline] __do_sys_recvmsg net/socket.c:2893 [inline] __se_sys_recvmsg net/socket.c:2890 [inline] __x64_sys_recvmsg+0x1ba/0x2a0 net/socket.c:2890 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888110c9a180 which belongs to the cache kmalloc-64 of size 64 The buggy address is located 32 bytes inside of freed 64-byte region [ffff888110c9a180, ffff888110c9a1c0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x110c9a flags: 0x17ff00000000000(node=0|zone=2|lastcpupid=0x7ff) page_type: f5(slab) raw: 017ff00000000000 ffff8881000418c0 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800200020 00000000f5000000 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 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 26, tgid 26 (kworker/u9:0), ts 20518825132, free_ts 20518815181 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1868 prep_new_page mm/page_alloc.c:1876 [inline] get_page_from_freelist+0x24ba/0x2540 mm/page_alloc.c:3956 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5236 alloc_slab_page mm/slub.c:3292 [inline] allocate_slab+0x77/0x660 mm/slub.c:3481 new_slab mm/slub.c:3539 [inline] refill_objects+0x331/0x3c0 mm/slub.c:7175 refill_sheaf mm/slub.c:2812 [inline] __pcs_replace_empty_main+0x2e6/0x730 mm/slub.c:4615 alloc_from_pcs mm/slub.c:4717 [inline] slab_alloc_node mm/slub.c:4851 [inline] __do_kmalloc_node mm/slub.c:5259 [inline] __kmalloc_node_noprof+0x577/0x7c0 mm/slub.c:5266 kmalloc_node_noprof include/linux/slab.h:1081 [inline] __vmalloc_area_node mm/vmalloc.c:3857 [inline] __vmalloc_node_range_noprof+0x5ef/0x1750 mm/vmalloc.c:4064 __vmalloc_node_noprof+0xc2/0x100 mm/vmalloc.c:4124 alloc_thread_stack_node kernel/fork.c:355 [inline] dup_task_struct+0x27b/0x800 kernel/fork.c:924 copy_process+0x508/0x3cd0 kernel/fork.c:2050 kernel_clone+0x248/0x8e0 kernel/fork.c:2653 user_mode_thread+0x110/0x180 kernel/fork.c:2729 call_usermodehelper_exec_work+0x5c/0x230 kernel/umh.c:171 process_one_work kernel/workqueue.c:3276 [inline] process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440 page last free pid 26 tgid 26 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1412 [inline] __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2953 __kasan_populate_vmalloc_do mm/kasan/shadow.c:393 [inline] __kasan_populate_vmalloc+0x1b2/0x1d0 mm/kasan/shadow.c:424 kasan_populate_vmalloc include/linux/kasan.h:580 [inline] alloc_vmap_area+0xd73/0x14b0 mm/vmalloc.c:2123 __get_vm_area_node+0x1f8/0x300 mm/vmalloc.c:3226 __vmalloc_node_range_noprof+0x36a/0x1750 mm/vmalloc.c:4024 __vmalloc_node_noprof+0xc2/0x100 mm/vmalloc.c:4124 alloc_thread_stack_node kernel/fork.c:355 [inline] dup_task_struct+0x27b/0x800 kernel/fork.c:924 copy_process+0x508/0x3cd0 kernel/fork.c:2050 kernel_clone+0x248/0x8e0 kernel/fork.c:2653 user_mode_thread+0x110/0x180 kernel/fork.c:2729 call_usermodehelper_exec_work+0x5c/0x230 kernel/umh.c:171 process_one_work kernel/workqueue.c:3276 [inline] process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff888110c9a080: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff888110c9a100: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc >ffff888110c9a180: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff888110c9a200: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc ffff888110c9a280: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc ================================================================== *** KASAN: slab-use-after-free Read in netlink_dump_done tree: torvalds URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux base: 0b5e8d7999076ac3c490fc18376a404e2626abff arch: amd64 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 config: https://ci.syzbot.org/builds/cb46a152-33c1-4b5e-bb75-bab2ecb45113/config syz repro: https://ci.syzbot.org/findings/86101c1f-0d2b-420f-a6bb-cd0260a6b2f5/syz_repro ================================================================== BUG: KASAN: slab-use-after-free in nlmsg_put_answer include/net/netlink.h:1041 [inline] BUG: KASAN: slab-use-after-free in netlink_dump_done+0x54d/0x890 net/netlink/af_netlink.c:2228 Read of size 4 at addr ffff8881bb35b9b4 by task syz.0.279/6738 CPU: 0 UID: 0 PID: 6738 Comm: syz.0.279 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 nlmsg_put_answer include/net/netlink.h:1041 [inline] netlink_dump_done+0x54d/0x890 net/netlink/af_netlink.c:2228 netlink_dump+0xacb/0xf40 net/netlink/af_netlink.c:2365 netlink_recvmsg+0x690/0xa50 net/netlink/af_netlink.c:1972 sock_recvmsg_nosec net/socket.c:1078 [inline] sock_recvmsg+0x172/0x1b0 net/socket.c:1100 sock_read_iter+0x251/0x320 net/socket.c:1170 new_sync_read fs/read_write.c:493 [inline] vfs_read+0x582/0xa70 fs/read_write.c:574 ksys_read+0x150/0x270 fs/read_write.c:717 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb5eaf9c819 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb5ebe08028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007fb5eb215fa0 RCX: 00007fb5eaf9c819 RDX: 000000000000009b RSI: 00002000000003c0 RDI: 0000000000000004 RBP: 00007fb5eb032c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb5eb216038 R14: 00007fb5eb215fa0 R15: 00007ffc181c9c68 Allocated by task 6739: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4538 [inline] slab_alloc_node mm/slub.c:4866 [inline] kmem_cache_alloc_node_noprof+0x384/0x690 mm/slub.c:4918 __alloc_skb+0x1d0/0x7d0 net/core/skbuff.c:702 netlink_sendmsg+0x5d4/0xb40 net/netlink/af_netlink.c:1865 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6739: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2685 [inline] slab_free mm/slub.c:6165 [inline] kmem_cache_free+0x189/0x630 mm/slub.c:6295 netlink_unicast_kernel net/netlink/af_netlink.c:1315 [inline] netlink_unicast+0x817/0x9b0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1890 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff8881bb35b980 which belongs to the cache skbuff_head_cache of size 240 The buggy address is located 52 bytes inside of freed 240-byte region [ffff8881bb35b980, ffff8881bb35ba70) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8881bb35b200 pfn:0x1bb35a head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x57ff00000000240(workingset|head|node=1|zone=2|lastcpupid=0x7ff) page_type: f5(slab) raw: 057ff00000000240 ffff888160417a00 ffff88816041db88 ffffea0005cae210 raw: ffff8881bb35b200 000000080015000f 00000000f5000000 0000000000000000 head: 057ff00000000240 ffff888160417a00 ffff88816041db88 ffffea0005cae210 head: ffff8881bb35b200 000000080015000f 00000000f5000000 0000000000000000 head: 057ff00000000001 ffffffffffffff81 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5552, tgid 5552 (dhcpcd), ts 37959428622, free_ts 37819349212 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1868 prep_new_page mm/page_alloc.c:1876 [inline] get_page_from_freelist+0x24ba/0x2540 mm/page_alloc.c:3956 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5236 alloc_slab_page mm/slub.c:3292 [inline] allocate_slab+0x77/0x660 mm/slub.c:3481 new_slab mm/slub.c:3539 [inline] refill_objects+0x331/0x3c0 mm/slub.c:7175 refill_sheaf mm/slub.c:2812 [inline] __pcs_replace_empty_main+0x2e6/0x730 mm/slub.c:4615 alloc_from_pcs mm/slub.c:4717 [inline] slab_alloc_node mm/slub.c:4851 [inline] kmem_cache_alloc_node_noprof+0x441/0x690 mm/slub.c:4918 __alloc_skb+0x1d0/0x7d0 net/core/skbuff.c:702 alloc_skb include/linux/skbuff.h:1383 [inline] alloc_skb_with_frags+0xc8/0x760 net/core/skbuff.c:6763 sock_alloc_send_pskb+0x878/0x990 net/core/sock.c:2995 unix_dgram_sendmsg+0x460/0x18e0 net/unix/af_unix.c:2127 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] sock_write_iter+0x49b/0x4f0 net/socket.c:1195 do_iter_readv_writev+0x619/0x8c0 fs/read_write.c:-1 vfs_writev+0x33c/0x990 fs/read_write.c:1059 do_writev+0x154/0x2e0 fs/read_write.c:1105 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 page last free pid 5552 tgid 5552 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1412 [inline] __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2953 mm_free_pgd kernel/fork.c:585 [inline] __mmdrop+0xb5/0x750 kernel/fork.c:727 mmdrop include/linux/sched/mm.h:55 [inline] mmdrop_sched include/linux/sched/mm.h:83 [inline] mmdrop_lazy_tlb_sched include/linux/sched/mm.h:110 [inline] finish_task_switch+0x449/0x920 kernel/sched/core.c:5180 context_switch kernel/sched/core.c:5301 [inline] __schedule+0x15e5/0x52d0 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0x164/0x360 kernel/sched/core.c:7008 schedule_hrtimeout_range_clock+0x1e7/0x320 kernel/time/sleep_timeout.c:207 poll_schedule_timeout+0xd0/0x1a0 fs/select.c:241 do_poll fs/select.c:954 [inline] do_sys_poll+0x7e8/0x1120 fs/select.c:1004 __do_sys_ppoll fs/select.c:1106 [inline] __se_sys_ppoll+0x209/0x2b0 fs/select.c:1086 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff8881bb35b880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc ffff8881bb35b900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8881bb35b980: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881bb35ba00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc ffff8881bb35ba80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== *** KASAN: slab-use-after-free Read in netlink_rcv_skb tree: torvalds URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux base: 0b5e8d7999076ac3c490fc18376a404e2626abff arch: amd64 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 config: https://ci.syzbot.org/builds/cb46a152-33c1-4b5e-bb75-bab2ecb45113/config syz repro: https://ci.syzbot.org/findings/584da8f1-c227-495f-aa8f-564d0bcc212f/syz_repro ================================================================== BUG: KASAN: slab-use-after-free in netlink_rcv_skb+0x395/0x4b0 net/netlink/af_netlink.c:2574 Read of size 4 at addr ffff8881753dc700 by task syz.2.60/6106 CPU: 1 UID: 0 PID: 6106 Comm: syz.2.60 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 netlink_rcv_skb+0x395/0x4b0 net/netlink/af_netlink.c:2574 nfnetlink_rcv+0x2c0/0x27b0 net/netfilter/nfnetlink.c:669 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1890 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4d3a59c819 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4d3b3b8028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f4d3a816090 RCX: 00007f4d3a59c819 RDX: 0000000000000080 RSI: 0000200000000100 RDI: 0000000000000003 RBP: 00007f4d3a632c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4d3a816128 R14: 00007f4d3a816090 R15: 00007ffd69453fe8 Allocated by task 6106: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4538 [inline] slab_alloc_node mm/slub.c:4866 [inline] kmem_cache_alloc_node_noprof+0x384/0x690 mm/slub.c:4918 kmalloc_reserve net/core/skbuff.c:613 [inline] __alloc_skb+0x27d/0x7d0 net/core/skbuff.c:713 netlink_sendmsg+0x5d4/0xb40 net/netlink/af_netlink.c:1865 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6106: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2685 [inline] slab_free mm/slub.c:6165 [inline] kmem_cache_free+0x189/0x630 mm/slub.c:6295 skb_kfree_head net/core/skbuff.c:1087 [inline] skb_free_head net/core/skbuff.c:1101 [inline] skb_release_data+0x81c/0xa80 net/core/skbuff.c:1128 skb_release_all net/core/skbuff.c:1203 [inline] __kfree_skb+0x5d/0x210 net/core/skbuff.c:1217 netlink_dump+0xbe9/0xf40 net/netlink/af_netlink.c:2385 __netlink_dump_start+0x5cb/0x7e0 net/netlink/af_netlink.c:2455 netlink_dump_start include/linux/netlink.h:341 [inline] ip_set_dump+0x15b/0x1f0 net/netfilter/ipset/ip_set_core.c:1717 nfnetlink_rcv_msg+0xc00/0x12c0 net/netfilter/nfnetlink.c:302 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2565 nfnetlink_rcv+0x2c0/0x27b0 net/netfilter/nfnetlink.c:669 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1890 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff8881753dc700 which belongs to the cache skbuff_small_head of size 704 The buggy address is located 0 bytes inside of freed 704-byte region [ffff8881753dc700, ffff8881753dc9c0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8881753dfb80 pfn:0x1753dc head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x57ff00000000240(workingset|head|node=1|zone=2|lastcpupid=0x7ff) page_type: f5(slab) raw: 057ff00000000240 ffff888160419140 ffffea0005d40010 ffffea0006e4bb10 raw: ffff8881753dfb80 000000080012000f 00000000f5000000 0000000000000000 head: 057ff00000000240 ffff888160419140 ffffea0005d40010 ffffea0006e4bb10 head: ffff8881753dfb80 000000080012000f 00000000f5000000 0000000000000000 head: 057ff00000000002 ffffffffffffff01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5839, tgid 5839 (syz-executor), ts 58323168360, free_ts 35463810625 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1868 prep_new_page mm/page_alloc.c:1876 [inline] get_page_from_freelist+0x24ba/0x2540 mm/page_alloc.c:3956 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5236 alloc_slab_page mm/slub.c:3292 [inline] allocate_slab+0x77/0x660 mm/slub.c:3481 new_slab mm/slub.c:3539 [inline] refill_objects+0x331/0x3c0 mm/slub.c:7175 refill_sheaf mm/slub.c:2812 [inline] __pcs_replace_empty_main+0x2e6/0x730 mm/slub.c:4615 alloc_from_pcs mm/slub.c:4717 [inline] slab_alloc_node mm/slub.c:4851 [inline] kmem_cache_alloc_node_noprof+0x441/0x690 mm/slub.c:4918 kmalloc_reserve net/core/skbuff.c:613 [inline] __alloc_skb+0x27d/0x7d0 net/core/skbuff.c:713 alloc_skb include/linux/skbuff.h:1383 [inline] nlmsg_new include/net/netlink.h:1055 [inline] inet6_netconf_notify_devconf+0x10f/0x1d0 net/ipv6/addrconf.c:592 __addrconf_sysctl_register+0x45a/0x4d0 net/ipv6/addrconf.c:7338 addrconf_sysctl_register+0x168/0x1c0 net/ipv6/addrconf.c:7375 ipv6_add_dev+0xd26/0x13a0 net/ipv6/addrconf.c:459 addrconf_notify+0x771/0x1050 net/ipv6/addrconf.c:3654 notifier_call_chain+0x1be/0x400 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline] call_netdevice_notifiers net/core/dev.c:2301 [inline] register_netdevice+0x173a/0x1cf0 net/core/dev.c:11462 register_netdev+0x40/0x60 net/core/dev.c:11540 page last free pid 5256 tgid 5256 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1412 [inline] __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2953 __slab_free+0x263/0x2b0 mm/slub.c:5573 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4538 [inline] slab_alloc_node mm/slub.c:4866 [inline] kmem_cache_alloc_node_noprof+0x384/0x690 mm/slub.c:4918 __alloc_skb+0x1d0/0x7d0 net/core/skbuff.c:702 netlink_sendmsg+0x5d4/0xb40 net/netlink/af_netlink.c:1865 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff8881753dc600: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff8881753dc680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8881753dc700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881753dc780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881753dc800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== *** KASAN: slab-use-after-free Read in rdma_nl_rcv tree: torvalds URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux base: 0b5e8d7999076ac3c490fc18376a404e2626abff arch: amd64 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 config: https://ci.syzbot.org/builds/cb46a152-33c1-4b5e-bb75-bab2ecb45113/config syz repro: https://ci.syzbot.org/findings/5022ea7e-727a-4c37-8ae5-0c7f5d43822c/syz_repro ================================================================== BUG: KASAN: slab-use-after-free in rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:248 [inline] BUG: KASAN: slab-use-after-free in rdma_nl_rcv+0x867/0xa10 drivers/infiniband/core/netlink.c:259 Read of size 4 at addr ffff8881a4036a00 by task syz.1.18/5983 CPU: 1 UID: 0 PID: 5983 Comm: syz.1.18 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:248 [inline] rdma_nl_rcv+0x867/0xa10 drivers/infiniband/core/netlink.c:259 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1890 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f737179c819 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f73725f1028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f7371a16090 RCX: 00007f737179c819 RDX: 0000000020008000 RSI: 0000200000000000 RDI: 0000000000000003 RBP: 00007f7371832c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7371a16128 R14: 00007f7371a16090 R15: 00007ffeff477318 Allocated by task 5983: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4538 [inline] slab_alloc_node mm/slub.c:4866 [inline] kmem_cache_alloc_node_noprof+0x384/0x690 mm/slub.c:4918 kmalloc_reserve net/core/skbuff.c:613 [inline] __alloc_skb+0x27d/0x7d0 net/core/skbuff.c:713 netlink_sendmsg+0x5d4/0xb40 net/netlink/af_netlink.c:1865 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 5983: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2685 [inline] slab_free mm/slub.c:6165 [inline] kmem_cache_free+0x189/0x630 mm/slub.c:6295 skb_kfree_head net/core/skbuff.c:1087 [inline] skb_free_head net/core/skbuff.c:1101 [inline] skb_release_data+0x81c/0xa80 net/core/skbuff.c:1128 skb_release_all net/core/skbuff.c:1203 [inline] __kfree_skb+0x5d/0x210 net/core/skbuff.c:1217 netlink_dump+0xbe9/0xf40 net/netlink/af_netlink.c:2385 __netlink_dump_start+0x5cb/0x7e0 net/netlink/af_netlink.c:2455 netlink_dump_start include/linux/netlink.h:341 [inline] rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:190 [inline] rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline] rdma_nl_rcv+0x78b/0xa10 drivers/infiniband/core/netlink.c:259 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1890 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff8881a4036a00 which belongs to the cache skbuff_small_head of size 704 The buggy address is located 0 bytes inside of freed 704-byte region [ffff8881a4036a00, ffff8881a4036cc0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1a4034 head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x57ff00000000040(head|node=1|zone=2|lastcpupid=0x7ff) page_type: f5(slab) raw: 057ff00000000040 ffff888160416c80 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800120012 00000000f5000000 0000000000000000 head: 057ff00000000040 ffff888160416c80 dead000000000100 dead000000000122 head: 0000000000000000 0000000800120012 00000000f5000000 0000000000000000 head: 057ff00000000002 ffffffffffffff01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5931, tgid 5931 (syz-executor), ts 61730251789, free_ts 58082311635 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1868 prep_new_page mm/page_alloc.c:1876 [inline] get_page_from_freelist+0x24ba/0x2540 mm/page_alloc.c:3956 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5236 alloc_slab_page mm/slub.c:3292 [inline] allocate_slab+0x77/0x660 mm/slub.c:3481 new_slab mm/slub.c:3539 [inline] refill_objects+0x331/0x3c0 mm/slub.c:7175 refill_sheaf mm/slub.c:2812 [inline] __pcs_replace_empty_main+0x2e6/0x730 mm/slub.c:4615 alloc_from_pcs mm/slub.c:4717 [inline] slab_alloc_node mm/slub.c:4851 [inline] kmem_cache_alloc_node_noprof+0x441/0x690 mm/slub.c:4918 kmalloc_reserve net/core/skbuff.c:613 [inline] __alloc_skb+0x27d/0x7d0 net/core/skbuff.c:713 alloc_skb include/linux/skbuff.h:1383 [inline] nlmsg_new include/net/netlink.h:1055 [inline] netlink_ack+0x146/0xa50 net/netlink/af_netlink.c:2502 netlink_rcv_skb+0x2b6/0x4b0 net/netlink/af_netlink.c:2571 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1890 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] __sys_sendto+0x672/0x710 net/socket.c:2206 __do_sys_sendto net/socket.c:2213 [inline] __se_sys_sendto net/socket.c:2209 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2209 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 5865 tgid 5865 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1412 [inline] __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2953 vfree+0x1d1/0x2f0 mm/vmalloc.c:3472 kcov_put kernel/kcov.c:442 [inline] kcov_close+0x28/0x50 kernel/kcov.c:543 __fput+0x44f/0xa70 fs/file_table.c:469 task_work_run+0x1d9/0x270 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x70f/0x22c0 kernel/exit.c:976 do_group_exit+0x21b/0x2d0 kernel/exit.c:1118 get_signal+0x1284/0x1330 kernel/signal.c:3034 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff8881a4036900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881a4036980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8881a4036a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881a4036a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881a4036b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== *** KASAN: slab-use-after-free Write in genl_done tree: torvalds URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux base: 0b5e8d7999076ac3c490fc18376a404e2626abff arch: amd64 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 config: https://ci.syzbot.org/builds/cb46a152-33c1-4b5e-bb75-bab2ecb45113/config syz repro: https://ci.syzbot.org/findings/5600aed0-e730-40d2-943c-84f525e427c6/syz_repro ================================================================== BUG: KASAN: slab-use-after-free in genl_done+0x76/0x220 net/netlink/genetlink.c:1038 Write of size 8 at addr ffff88811b796788 by task syz.0.34/6007 CPU: 0 UID: 0 PID: 6007 Comm: syz.0.34 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 genl_done+0x76/0x220 net/netlink/genetlink.c:1038 netlink_dump_cleanup+0x99/0x120 net/netlink/af_netlink.c:2259 netlink_dump+0xbe9/0xf40 net/netlink/af_netlink.c:2385 __netlink_dump_start+0x5cb/0x7e0 net/netlink/af_netlink.c:2455 genl_family_rcv_msg_dumpit+0x213/0x310 net/netlink/genetlink.c:1075 genl_family_rcv_msg net/netlink/genetlink.c:1191 [inline] genl_rcv_msg+0x5e8/0x7a0 net/netlink/genetlink.c:1209 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2565 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1890 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe33999c819 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe33a8da028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fe339c16090 RCX: 00007fe33999c819 RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000000000000004 RBP: 00007fe339a32c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe339c16128 R14: 00007fe339c16090 R15: 00007ffe15e728b8 Allocated by task 6007: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5380 kmalloc_noprof include/linux/slab.h:950 [inline] genl_dumpit_info_alloc net/netlink/genetlink.c:915 [inline] genl_start+0x1c9/0x6c0 net/netlink/genetlink.c:985 __netlink_dump_start+0x469/0x7e0 net/netlink/af_netlink.c:2446 genl_family_rcv_msg_dumpit+0x213/0x310 net/netlink/genetlink.c:1075 genl_family_rcv_msg net/netlink/genetlink.c:1191 [inline] genl_rcv_msg+0x5e8/0x7a0 net/netlink/genetlink.c:1209 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2565 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1890 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6006: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2685 [inline] slab_free mm/slub.c:6165 [inline] kfree+0x1c5/0x640 mm/slub.c:6483 genl_dumpit_info_free net/netlink/genetlink.c:920 [inline] genl_done+0x1c8/0x220 net/netlink/genetlink.c:1046 netlink_dump_cleanup+0x99/0x120 net/netlink/af_netlink.c:2259 netlink_dump+0xbe9/0xf40 net/netlink/af_netlink.c:2385 netlink_recvmsg+0x690/0xa50 net/netlink/af_netlink.c:1972 sock_recvmsg_nosec net/socket.c:1078 [inline] sock_recvmsg+0x172/0x1b0 net/socket.c:1100 sock_read_iter+0x251/0x320 net/socket.c:1170 new_sync_read fs/read_write.c:493 [inline] vfs_read+0x582/0xa70 fs/read_write.c:574 ksys_read+0x150/0x270 fs/read_write.c:717 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88811b796700 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 136 bytes inside of freed 192-byte region [ffff88811b796700, ffff88811b7967c0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11b796 flags: 0x17ff00000000000(node=0|zone=2|lastcpupid=0x7ff) page_type: f5(slab) raw: 017ff00000000000 ffff8881000413c0 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800100010 00000000f5000000 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 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5922, tgid 5922 (syz-executor), ts 64892204905, free_ts 61400269257 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1868 prep_new_page mm/page_alloc.c:1876 [inline] get_page_from_freelist+0x24ba/0x2540 mm/page_alloc.c:3956 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5236 alloc_slab_page mm/slub.c:3292 [inline] allocate_slab+0x77/0x660 mm/slub.c:3481 new_slab mm/slub.c:3539 [inline] refill_objects+0x331/0x3c0 mm/slub.c:7175 refill_sheaf mm/slub.c:2812 [inline] __pcs_replace_empty_main+0x2e6/0x730 mm/slub.c:4615 alloc_from_pcs mm/slub.c:4717 [inline] slab_alloc_node mm/slub.c:4851 [inline] __do_kmalloc_node mm/slub.c:5259 [inline] __kmalloc_node_noprof+0x577/0x7c0 mm/slub.c:5266 kmalloc_node_noprof include/linux/slab.h:1081 [inline] alloc_slab_obj_exts+0xbf/0x250 mm/slub.c:2167 __memcg_slab_post_alloc_hook+0x5c4/0xe80 mm/memcontrol.c:3466 memcg_slab_post_alloc_hook mm/slub.c:2457 [inline] slab_post_alloc_hook mm/slub.c:4549 [inline] slab_alloc_node mm/slub.c:4866 [inline] kmem_cache_alloc_noprof+0x347/0x650 mm/slub.c:4873 vm_area_dup+0x2b/0x680 mm/vma_init.c:123 dup_mmap+0x8b1/0x1d90 mm/mmap.c:1786 dup_mm kernel/fork.c:1531 [inline] copy_mm+0x13b/0x4a0 kernel/fork.c:1583 copy_process+0x18b6/0x3cd0 kernel/fork.c:2223 kernel_clone+0x248/0x8e0 kernel/fork.c:2653 __do_sys_clone kernel/fork.c:2794 [inline] __se_sys_clone kernel/fork.c:2778 [inline] __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2778 page last free pid 10 tgid 10 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1412 [inline] __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2953 kasan_depopulate_vmalloc_pte+0x6d/0x90 mm/kasan/shadow.c:484 apply_to_pte_range mm/memory.c:3322 [inline] apply_to_pmd_range mm/memory.c:3366 [inline] apply_to_pud_range mm/memory.c:3402 [inline] apply_to_p4d_range mm/memory.c:3438 [inline] __apply_to_page_range+0xbdc/0x1420 mm/memory.c:3474 __kasan_release_vmalloc+0xa2/0xd0 mm/kasan/shadow.c:602 kasan_release_vmalloc include/linux/kasan.h:593 [inline] kasan_release_vmalloc_node mm/vmalloc.c:2284 [inline] purge_vmap_node+0x220/0x960 mm/vmalloc.c:2306 __purge_vmap_area_lazy+0x779/0xb70 mm/vmalloc.c:2396 drain_vmap_area_work+0x27/0x40 mm/vmalloc.c:2430 process_one_work kernel/workqueue.c:3276 [inline] process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff88811b796680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88811b796700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88811b796780: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff88811b796800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88811b796880: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc ================================================================== *** If these findings have caused you to resend the series or submit a separate fix, please add the following tag to your commit message: Tested-by: syzbot@syzkaller.appspotmail.com --- This report is generated by a bot. 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