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Tue, 30 Jul 2019 23:38:06 -0700 (PDT) Date: Tue, 30 Jul 2019 23:38:06 -0700 In-Reply-To: <000000000000de000a058e9025db@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000002677cc058ef45ea5@google.com> Subject: Re: KASAN: use-after-free Read in release_sock From: syzbot To: davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org syzbot has found a reproducer for the following crash on: HEAD commit: 629f8205 Merge tag 'for-linus-20190730' of git://git.kerne.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=11a27744600000 kernel config: https://syzkaller.appspot.com/x/.config?x=4c7b914a2680c9c6 dashboard link: https://syzkaller.appspot.com/bug?extid=107429d62fb1d293602f compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16a7c8dc600000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1498cfa2600000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+107429d62fb1d293602f@syzkaller.appspotmail.com ================================================================== BUG: KASAN: use-after-free in debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline] BUG: KASAN: use-after-free in do_raw_spin_lock+0x28a/0x2e0 kernel/locking/spinlock_debug.c:112 Read of size 4 at addr ffff8880a81b540c by task syz-executor143/10205 CPU: 1 PID: 10205 Comm: syz-executor143 Not tainted 5.3.0-rc2+ #90 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+0xd4/0x306 mm/kasan/report.c:351 __kasan_report.cold+0x1b/0x36 mm/kasan/report.c:482 kasan_report+0x12/0x17 mm/kasan/common.c:612 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131 debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline] do_raw_spin_lock+0x28a/0x2e0 kernel/locking/spinlock_debug.c:112 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:136 [inline] _raw_spin_lock_bh+0x3b/0x50 kernel/locking/spinlock.c:175 spin_lock_bh include/linux/spinlock.h:343 [inline] release_sock+0x20/0x1c0 net/core/sock.c:2932 nr_release+0x303/0x3e0 net/netrom/af_netrom.c:553 __sock_release+0xce/0x280 net/socket.c:590 sock_close+0x1e/0x30 net/socket.c:1268 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x92f/0x2e50 kernel/exit.c:879 do_group_exit+0x135/0x360 kernel/exit.c:983 get_signal+0x47c/0x2500 kernel/signal.c:2729 do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815 exit_to_usermode_loop+0x286/0x380 arch/x86/entry/common.c:159 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:299 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x447d09 Code: Bad RIP value. RSP: 002b:00007fca48b63db8 EFLAGS: 00000246 ORIG_RAX: 000000000000002b RAX: fffffffffffffe00 RBX: 00000000006ddc58 RCX: 0000000000447d09 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000007 RBP: 00000000006ddc50 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006ddc5c R13: 00007ffe913f3ebf R14: 00007fca48b649c0 R15: 0000000000000001 Allocated by task 0: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_kmalloc mm/kasan/common.c:487 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:460 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:501 __do_kmalloc mm/slab.c:3655 [inline] __kmalloc+0x163/0x770 mm/slab.c:3664 kmalloc include/linux/slab.h:557 [inline] sk_prot_alloc+0x23a/0x310 net/core/sock.c:1603 sk_alloc+0x39/0xf70 net/core/sock.c:1657 nr_make_new net/netrom/af_netrom.c:476 [inline] nr_rx_frame+0x733/0x1e73 net/netrom/af_netrom.c:959 nr_loopback_timer+0x7b/0x170 net/netrom/nr_loopback.c:59 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1322 expire_timers kernel/time/timer.c:1366 [inline] __run_timers kernel/time/timer.c:1685 [inline] __run_timers kernel/time/timer.c:1653 [inline] run_timer_softirq+0x697/0x17a0 kernel/time/timer.c:1698 __do_softirq+0x262/0x98c kernel/softirq.c:292 Freed by task 10205: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:449 kasan_slab_free+0xe/0x10 mm/kasan/common.c:457 __cache_free mm/slab.c:3425 [inline] kfree+0x10a/0x2c0 mm/slab.c:3756 sk_prot_free net/core/sock.c:1640 [inline] __sk_destruct+0x4f7/0x6e0 net/core/sock.c:1726 sk_destruct+0x86/0xa0 net/core/sock.c:1734 __sk_free+0xfb/0x360 net/core/sock.c:1745 sk_free+0x42/0x50 net/core/sock.c:1756 sock_put include/net/sock.h:1725 [inline] nr_destroy_socket+0x3ea/0x4a0 net/netrom/af_netrom.c:288 nr_release+0x347/0x3e0 net/netrom/af_netrom.c:530 __sock_release+0xce/0x280 net/socket.c:590 sock_close+0x1e/0x30 net/socket.c:1268 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x92f/0x2e50 kernel/exit.c:879 do_group_exit+0x135/0x360 kernel/exit.c:983 get_signal+0x47c/0x2500 kernel/signal.c:2729 do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815 exit_to_usermode_loop+0x286/0x380 arch/x86/entry/common.c:159 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:299 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880a81b5380 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 140 bytes inside of 2048-byte region [ffff8880a81b5380, ffff8880a81b5b80) The buggy address belongs to the page: page:ffffea0002a06d00 refcount:1 mapcount:0 mapping:ffff8880aa400e00 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea0002a0ec88 ffffea0002a07708 ffff8880aa400e00 raw: 0000000000000000 ffff8880a81b4280 0000000100000003 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a81b5300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880a81b5380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8880a81b5400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a81b5480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a81b5500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================