On Thu, May 16, 2019 at 3:35 AM syzbot <syzbot+0025447b4cb6f2085...@syzkaller.appspotmail.com> wrote: > > Hello, > > syzbot found the following crash on: > > HEAD commit: 3b0f31f2 genetlink: make policy common to family > git tree: net-next > console output: https://syzkaller.appspot.com/x/log.txt?x=12a319df200000 > kernel config: https://syzkaller.appspot.com/x/.config?x=f05902bca21d8935 > dashboard link: https://syzkaller.appspot.com/bug?extid=0025447b4cb6f208558f > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > Unfortunately, I don't have any reproducer for this crash yet. > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+0025447b4cb6f2085...@syzkaller.appspotmail.com
This looks like what has been fixed by: #syz fix: xfrm: policy: Fix out-of-bound array accesses in __xfrm_policy_unlink > ================================================================== > BUG: KASAN: use-after-free in __write_once_size > include/linux/compiler.h:220 [inline] > BUG: KASAN: use-after-free in __hlist_del include/linux/list.h:713 [inline] > BUG: KASAN: use-after-free in hlist_del_rcu include/linux/rculist.h:455 > [inline] > BUG: KASAN: use-after-free in __xfrm_policy_unlink+0x4b1/0x5c0 > net/xfrm/xfrm_policy.c:2212 > Write of size 8 at addr ffff8880a55a9e80 by task kworker/u4:6/7431 > > CPU: 1 PID: 7431 Comm: kworker/u4:6 Not tainted 5.0.0+ #106 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Workqueue: netns cleanup_net > 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:187 > kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 > __asan_report_store8_noabort+0x17/0x20 mm/kasan/generic_report.c:137 > __write_once_size include/linux/compiler.h:220 [inline] > __hlist_del include/linux/list.h:713 [inline] > hlist_del_rcu include/linux/rculist.h:455 [inline] > __xfrm_policy_unlink+0x4b1/0x5c0 net/xfrm/xfrm_policy.c:2212 > xfrm_policy_flush+0x331/0x460 net/xfrm/xfrm_policy.c:1789 > xfrm_policy_fini+0x49/0x3a0 net/xfrm/xfrm_policy.c:3871 > xfrm_net_exit+0x1d/0x70 net/xfrm/xfrm_policy.c:3933 > ops_exit_list.isra.0+0xb0/0x160 net/core/net_namespace.c:153 > cleanup_net+0x3fb/0x960 net/core/net_namespace.c:551 > process_one_work+0x98e/0x1790 kernel/workqueue.c:2269 > worker_thread+0x98/0xe40 kernel/workqueue.c:2415 > kthread+0x357/0x430 kernel/kthread.c:253 > ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 > > Allocated by task 7242: > save_stack+0x45/0xd0 mm/kasan/common.c:75 > set_track mm/kasan/common.c:87 [inline] > __kasan_kmalloc mm/kasan/common.c:497 [inline] > __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:470 > kasan_kmalloc+0x9/0x10 mm/kasan/common.c:511 > __do_kmalloc mm/slab.c:3726 [inline] > __kmalloc+0x15c/0x740 mm/slab.c:3735 > kmalloc include/linux/slab.h:550 [inline] > kzalloc include/linux/slab.h:740 [inline] > ext4_htree_store_dirent+0x8a/0x650 fs/ext4/dir.c:450 > htree_dirblock_to_tree+0x4fe/0x910 fs/ext4/namei.c:1021 > ext4_htree_fill_tree+0x252/0xa50 fs/ext4/namei.c:1098 > ext4_dx_readdir fs/ext4/dir.c:574 [inline] > ext4_readdir+0x1999/0x3490 fs/ext4/dir.c:121 > iterate_dir+0x489/0x5f0 fs/readdir.c:51 > __do_sys_getdents fs/readdir.c:231 [inline] > __se_sys_getdents fs/readdir.c:212 [inline] > __x64_sys_getdents+0x1dd/0x370 fs/readdir.c:212 > do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Freed by task 7242: > save_stack+0x45/0xd0 mm/kasan/common.c:75 > set_track mm/kasan/common.c:87 [inline] > __kasan_slab_free+0x102/0x150 mm/kasan/common.c:459 > kasan_slab_free+0xe/0x10 mm/kasan/common.c:467 > __cache_free mm/slab.c:3498 [inline] > kfree+0xcf/0x230 mm/slab.c:3821 > free_rb_tree_fname+0x87/0xe0 fs/ext4/dir.c:402 > ext4_htree_free_dir_info fs/ext4/dir.c:424 [inline] > ext4_release_dir+0x46/0x70 fs/ext4/dir.c:622 > __fput+0x2e5/0x8d0 fs/file_table.c:278 > ____fput+0x16/0x20 fs/file_table.c:309 > task_work_run+0x14a/0x1c0 kernel/task_work.c:113 > tracehook_notify_resume include/linux/tracehook.h:188 [inline] > exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166 > prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] > syscall_return_slowpath arch/x86/entry/common.c:268 [inline] > do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > The buggy address belongs to the object at ffff8880a55a9e80 > which belongs to the cache kmalloc-64 of size 64 > The buggy address is located 0 bytes inside of > 64-byte region [ffff8880a55a9e80, ffff8880a55a9ec0) > The buggy address belongs to the page: > page:ffffea0002956a40 count:1 mapcount:0 mapping:ffff88812c3f0340 index:0x0 > flags: 0x1fffc0000000200(slab) > raw: 01fffc0000000200 ffffea0002a0d748 ffffea00018af1c8 ffff88812c3f0340 > raw: 0000000000000000 ffff8880a55a9000 0000000100000020 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8880a55a9d80: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc > ffff8880a55a9e00: 00 00 00 00 04 fc fc fc fc fc fc fc fc fc fc fc > > ffff8880a55a9e80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ^ > ffff8880a55a9f00: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc > ffff8880a55a9f80: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc > ================================================================== > > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkal...@googlegroups.com. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > -- > You received this message because you are subscribed to the Google Groups > "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to syzkaller-bugs+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/syzkaller-bugs/000000000000cd5fdf0588fed11c%40google.com. > For more options, visit https://groups.google.com/d/optout.