================================================================== BUG: KASAN: slab-use-after-free in skb_reset_mac_header include/linux/skbuff.h:3109 [inline] BUG: KASAN: slab-use-after-free in napi_frags_skb net/core/gro.c:723 [inline] BUG: KASAN: slab-use-after-free in napi_gro_frags+0x1016/0x1210 net/core/gro.c:758 Read of size 8 at addr ffff888058ce5c58 by task syz.9.4659/24387 CPU: 2 UID: 0 PID: 24387 Comm: syz.9.4659 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 skb_reset_mac_header include/linux/skbuff.h:3109 [inline] napi_frags_skb net/core/gro.c:723 [inline] napi_gro_frags+0x1016/0x1210 net/core/gro.c:758 tun_get_user+0x2a92/0x3ce0 drivers/net/tun.c:1920 tun_chr_write_iter+0xdc/0x210 drivers/net/tun.c:1996 do_iter_readv_writev+0x65f/0x9e0 fs/read_write.c:827 vfs_writev+0x35f/0xde0 fs/read_write.c:1057 do_writev+0x132/0x340 fs/read_write.c:1103 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x7c/0x3a0 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7f35579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f545655c EFLAGS: 00000296 ORIG_RAX: 0000000000000092 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000080000500 RDX: 0000000000000003 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 24387: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:330 [inline] __kasan_mempool_unpoison_object+0x16d/0x1a0 mm/kasan/common.c:558 kasan_mempool_unpoison_object include/linux/kasan.h:388 [inline] napi_skb_cache_get+0x327/0x890 net/core/skbuff.c:295 __alloc_skb+0x131/0x380 net/core/skbuff.c:657 napi_alloc_skb+0x3fa/0x830 net/core/skbuff.c:811 napi_get_frags net/core/gro.c:673 [inline] napi_get_frags+0x5b/0x140 net/core/gro.c:668 tun_napi_alloc_frags drivers/net/tun.c:1404 [inline] tun_get_user+0x1e72/0x3ce0 drivers/net/tun.c:1784 tun_chr_write_iter+0xdc/0x210 drivers/net/tun.c:1996 do_iter_readv_writev+0x65f/0x9e0 fs/read_write.c:827 vfs_writev+0x35f/0xde0 fs/read_write.c:1057 do_writev+0x132/0x340 fs/read_write.c:1103 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x7c/0x3a0 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e Freed by task 24387: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x60/0x70 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2417 [inline] slab_free mm/slub.c:4680 [inline] kmem_cache_free+0x2d1/0x4d0 mm/slub.c:4782 kfree_skbmem+0x1a4/0x1f0 net/core/skbuff.c:1109 __kfree_skb net/core/skbuff.c:1166 [inline] consume_skb net/core/skbuff.c:1397 [inline] consume_skb+0xcc/0x100 net/core/skbuff.c:1391 skb_pp_cow_data+0x89e/0xff0 net/core/skbuff.c:969 skb_cow_data_for_xdp+0x88/0xb0 net/core/skbuff.c:985 netif_skb_check_for_xdp net/core/dev.c:5341 [inline] netif_receive_generic_xdp net/core/dev.c:5382 [inline] do_xdp_generic+0x530/0x1320 net/core/dev.c:5450 tun_get_user+0x1d43/0x3ce0 drivers/net/tun.c:1872 tun_chr_write_iter+0xdc/0x210 drivers/net/tun.c:1996 do_iter_readv_writev+0x65f/0x9e0 fs/read_write.c:827 vfs_writev+0x35f/0xde0 fs/read_write.c:1057 do_writev+0x132/0x340 fs/read_write.c:1103 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x7c/0x3a0 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e The buggy address belongs to the object at ffff888058ce5b80 which belongs to the cache skbuff_head_cache of size 240 The buggy address is located 216 bytes inside of freed 240-byte region [ffff888058ce5b80, ffff888058ce5c70) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x58ce4 head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 memcg:ffff88806bebd201 ksm flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 04fff00000000040 ffff8880416b2a00 ffffea0001412700 dead000000000003 raw: 0000000000000000 0000000080190019 00000000f5000000 ffff88806bebd201 head: 04fff00000000040 ffff8880416b2a00 ffffea0001412700 dead000000000003 head: 0000000000000000 0000000080190019 00000000f5000000 ffff88806bebd201 head: 04fff00000000001 ffffea0001633901 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 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 14592, tgid 14592 (kworker/u32:24), ts 699637426041, free_ts 698919630395 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1851 prep_new_page mm/page_alloc.c:1859 [inline] get_page_from_freelist+0x132b/0x38e0 mm/page_alloc.c:3858 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:5148 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:2487 [inline] allocate_slab mm/slub.c:2655 [inline] new_slab+0x247/0x330 mm/slub.c:2709 ___slab_alloc+0xcf2/0x1740 mm/slub.c:3891 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3981 __slab_alloc_node mm/slub.c:4056 [inline] slab_alloc_node mm/slub.c:4217 [inline] kmem_cache_alloc_node_noprof+0xf5/0x3b0 mm/slub.c:4281 __alloc_skb+0x2b2/0x380 net/core/skbuff.c:659 alloc_skb include/linux/skbuff.h:1336 [inline] nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:763 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:820 [inline] nsim_dev_trap_report_work+0x2b1/0xcf0 drivers/net/netdevsim/dev.c:866 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 page last free pid 15798 tgid 15798 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0x7d5/0x10f0 mm/page_alloc.c:2895 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:340 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4180 [inline] slab_alloc_node mm/slub.c:4229 [inline] kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4236 getname_flags.part.0+0x4c/0x550 fs/namei.c:146 getname_flags+0x93/0xf0 include/linux/audit.h:322 user_path_at+0x24/0x60 fs/namei.c:3126 ksys_umount fs/namespace.c:2112 [inline] __do_sys_umount fs/namespace.c:2120 [inline] __se_sys_umount fs/namespace.c:2118 [inline] __ia32_sys_umount+0x109/0x190 fs/namespace.c:2118 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x7c/0x3a0 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e Memory state around the buggy address: ffff888058ce5b00: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc ffff888058ce5b80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888058ce5c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc ^ ffff888058ce5c80: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ffff888058ce5d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi