================================================================== BUG: KASAN: use-after-free in inet_frag_destroy_rcu+0xd9/0xe0 net/ipv4/inet_fragment.c:201 Read of size 8 at addr ffff88808c49cd18 by task syz-executor.5/18831 CPU: 0 PID: 18831 Comm: syz-executor.5 Not tainted 5.2.0-rc1+ #3 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:188 __kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 kasan_report+0x12/0x20 mm/kasan/common.c:614 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132 inet_frag_destroy_rcu+0xd9/0xe0 net/ipv4/inet_fragment.c:201 __rcu_reclaim kernel/rcu/rcu.h:222 [inline] rcu_do_batch kernel/rcu/tree.c:2092 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2310 [inline] rcu_core+0xba5/0x1500 kernel/rcu/tree.c:2291 __do_softirq+0x25c/0x94c kernel/softirq.c:293 invoke_softirq kernel/softirq.c:374 [inline] irq_exit+0x180/0x1d0 kernel/softirq.c:414 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x13b/0x550 arch/x86/kernel/apic/apic.c:1068 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806 RIP: 0010:__write_once_size include/linux/compiler.h:221 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x48/0x50 kernel/kcov.c:110 Code: 75 2b 8b 90 e0 12 00 00 83 fa 02 75 20 48 8b 88 e8 12 00 00 8b 80 e4 12 00 00 48 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 <48> 89 11 5d c3 0f 1f 00 65 4c 8b 04 25 c0 fd 01 00 65 8b 05 b8 58 RSP: 0018:ffff88821af7f6e8 EFLAGS: 00000212 ORIG_RAX: ffffffffffffff13 RAX: 0000000000040000 RBX: ffffea000870eec0 RCX: ffffc90010882000 RDX: 000000000002f932 RSI: ffffffff818f6a55 RDI: 0000000000000007 RBP: ffff88821af7f6e8 R08: ffff888087294440 R09: ffffed1015d06be0 R10: ffffed1015d06bdf R11: ffff8880ae835efb R12: ffff8880ae830780 R13: dead000000000100 R14: ffffea000870eec8 R15: ffffea000870eec0 page_ref_count include/linux/page_ref.h:67 [inline] get_page include/linux/mm.h:1012 [inline] __lru_cache_add+0xa5/0x2d0 mm/swap.c:403 lru_cache_add+0x21c/0x590 mm/swap.c:441 add_to_page_cache_lru+0x349/0x760 mm/filemap.c:932 pagecache_get_page+0x357/0x850 mm/filemap.c:1655 grab_cache_page_write_begin+0x75/0xb0 mm/filemap.c:3156 ext4_da_write_begin+0x2d7/0xec0 fs/ext4/inode.c:3075 generic_perform_write+0x22a/0x520 mm/filemap.c:3206 __generic_file_write_iter+0x25e/0x630 mm/filemap.c:3335 ext4_file_write_iter+0x332/0x1070 fs/ext4/file.c:266 call_write_iter include/linux/fs.h:1872 [inline] new_sync_write+0x4d3/0x770 fs/read_write.c:483 __vfs_write+0xe1/0x110 fs/read_write.c:496 vfs_write+0x20c/0x580 fs/read_write.c:558 ksys_write+0x14f/0x290 fs/read_write.c:611 __do_sys_write fs/read_write.c:623 [inline] __se_sys_write fs/read_write.c:620 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:620 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459279 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f7445f64c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459279 RDX: 00000000000d46ad RSI: 0000000020000040 RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7445f656d4 R13: 00000000004c8e9b R14: 00000000004dfaf8 R15: 00000000ffffffff Allocated by task 11387: save_stack+0x23/0x90 mm/kasan/common.c:71 set_track mm/kasan/common.c:79 [inline] __kasan_kmalloc mm/kasan/common.c:489 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:503 kmem_cache_alloc_trace+0x151/0x750 mm/slab.c:3555 kmalloc include/linux/slab.h:547 [inline] kzalloc include/linux/slab.h:742 [inline] fqdir_init include/net/inet_frag.h:115 [inline] ipv6_frags_init_net+0x48/0x460 net/ipv6/reassembly.c:513 ops_init+0xb3/0x410 net/core/net_namespace.c:130 setup_net+0x2d3/0x740 net/core/net_namespace.c:316 copy_net_ns+0x1df/0x340 net/core/net_namespace.c:439 create_new_namespaces+0x400/0x7b0 kernel/nsproxy.c:107 unshare_nsproxy_namespaces+0xc2/0x200 kernel/nsproxy.c:206 ksys_unshare+0x440/0x980 kernel/fork.c:2692 __do_sys_unshare kernel/fork.c:2760 [inline] __se_sys_unshare kernel/fork.c:2758 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:2758 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 9437: save_stack+0x23/0x90 mm/kasan/common.c:71 set_track mm/kasan/common.c:79 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:451 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459 __cache_free mm/slab.c:3432 [inline] kfree+0xcf/0x220 mm/slab.c:3755 fqdir_rwork_fn+0x33/0x40 net/ipv4/inet_fragment.c:154 process_one_work+0x989/0x1790 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 kthread+0x354/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 The buggy address belongs to the object at ffff88808c49cd00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 24 bytes inside of 512-byte region [ffff88808c49cd00, ffff88808c49cf00) The buggy address belongs to the page: page:ffffea0002312700 refcount:1 mapcount:0 mapping:ffff8880aa400940 index:0x0 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea00023da888 ffffea00022cb9c8 ffff8880aa400940 raw: 0000000000000000 ffff88808c49c080 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808c49cc00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88808c49cc80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88808c49cd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88808c49cd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808c49ce00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================