On Sat, Mar 31, 2018 at 04:01:02PM -0700, syzbot wrote: > Hello, > > syzbot hit the following crash on bpf-next commit > 1379ef828a18d8f81c526b25e4d5685caa2cfd65 (Thu Mar 29 22:09:44 2018 +0000) > Merge branch 'bpf-sockmap-ingress' > syzbot dashboard link: > https://syzkaller.appspot.com/bug?extid=6eaf536fd743f5e119c5 > > So far this crash happened 6 times on bpf-next. > C reproducer: https://syzkaller.appspot.com/x/repro.c?id=6614614900998144 > syzkaller reproducer: > https://syzkaller.appspot.com/x/repro.syz?id=5035340528091136 > Raw console output: > https://syzkaller.appspot.com/x/log.txt?id=5063394046509056 > Kernel config: > https://syzkaller.appspot.com/x/.config?id=-1280663959502969741 > compiler: gcc (GCC) 7.1.1 20170620 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+6eaf536fd743f5e11...@syzkaller.appspotmail.com > It will help syzbot understand when the bug is fixed. See footer for > details. > If you forward the report, please keep this part and the footer. > > R13: 0000000000000005 R14: 0000000000001380 R15: 00007ffd314c8768 > ------------[ cut here ]------------ > ------------[ cut here ]------------ > refcount_t: increment on 0; use-after-free. > refcount_t: underflow; use-after-free. > WARNING: CPU: 1 PID: 4434 at lib/refcount.c:153 refcount_inc+0x47/0x50 > lib/refcount.c:153 > WARNING: CPU: 0 PID: 4437 at lib/refcount.c:187 > refcount_sub_and_test+0x167/0x1b0 lib/refcount.c:187 > Kernel panic - not syncing: panic_on_warn set ... > > Modules linked in: > CPU: 1 PID: 4434 Comm: syzkaller349430 Not tainted 4.16.0-rc6+ #41 > CPU: 0 PID: 4437 Comm: syzkaller349430 Not tainted 4.16.0-rc6+ #41 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > RIP: 0010:refcount_sub_and_test+0x167/0x1b0 lib/refcount.c:187 > Call Trace: > RSP: 0018:ffff8801b061f728 EFLAGS: 00010286 > __dump_stack lib/dump_stack.c:17 [inline] > dump_stack+0x194/0x24d lib/dump_stack.c:53 > RAX: dffffc0000000008 RBX: 0000000000000000 RCX: ffffffff815ba4be > RDX: 0000000000000000 RSI: 1ffff100360c3e95 RDI: 1ffff100360c3e6a > RBP: ffff8801b061f7b8 R08: 0000000000000000 R09: 0000000000000000 > R10: ffff8801b061f850 R11: 0000000000000000 R12: 1ffff100360c3ee6 > panic+0x1e4/0x41c kernel/panic.c:183 > R13: 00000000ffffffff R14: 0000000000000001 R15: ffff8801b1be4184 > FS: 0000000001817880(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007ffd314c9000 CR3: 00000001b04a1006 CR4: 00000000001606f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > __warn+0x1dc/0x200 kernel/panic.c:547 > report_bug+0x1f4/0x2b0 lib/bug.c:186 > fixup_bug.part.11+0x37/0x80 arch/x86/kernel/traps.c:178 > fixup_bug arch/x86/kernel/traps.c:247 [inline] > do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:296 > refcount_dec_and_test+0x1a/0x20 lib/refcount.c:212 > put_net include/net/net_namespace.h:222 [inline] > __sk_destruct+0x560/0x920 net/core/sock.c:1592 > do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315 > invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:986 > RIP: 0010:refcount_inc+0x47/0x50 lib/refcount.c:153 > RSP: 0018:ffff8801b058f860 EFLAGS: 00010286 > RAX: dffffc0000000008 RBX: ffff8801ab55a1c4 RCX: ffffffff815ba4be > RDX: 0000000000000000 RSI: 1ffff100360b1ebc RDI: 1ffff100360b1e91 > RBP: ffff8801b058f868 R08: 0000000000000000 R09: 0000000000000000 > sk_destruct+0x47/0x80 net/core/sock.c:1601 > R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801b058faf8 > __sk_free+0xf1/0x2b0 net/core/sock.c:1612 > R13: ffff8801af87b513 R14: ffff8801ab55a1c0 R15: ffff8801af87b501 > sk_free+0x2a/0x40 net/core/sock.c:1623 > sock_put include/net/sock.h:1661 [inline] > tcp_close+0x967/0x1190 net/ipv4/tcp.c:2329 > get_net include/net/net_namespace.h:204 [inline] > sk_alloc+0x3f9/0x1440 net/core/sock.c:1540 > inet_release+0xed/0x1c0 net/ipv4/af_inet.c:427 > sock_release+0x8d/0x1e0 net/socket.c:594 > sock_close+0x16/0x20 net/socket.c:1149 > __fput+0x327/0x7e0 fs/file_table.c:209 > ____fput+0x15/0x20 fs/file_table.c:243 > task_work_run+0x199/0x270 kernel/task_work.c:113 > inet_create+0x47c/0xf50 net/ipv4/af_inet.c:320 > tracehook_notify_resume include/linux/tracehook.h:191 [inline] > exit_to_usermode_loop+0x275/0x2f0 arch/x86/entry/common.c:166 > __sock_create+0x4d4/0x850 net/socket.c:1285 > prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] > syscall_return_slowpath arch/x86/entry/common.c:265 [inline] > do_syscall_64+0x6ec/0x940 arch/x86/entry/common.c:292 > sock_create net/socket.c:1325 [inline] > SYSC_socket net/socket.c:1355 [inline] > SyS_socket+0xeb/0x1d0 net/socket.c:1335 > do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 > entry_SYSCALL_64_after_hwframe+0x42/0xb7 > RIP: 0033:0x402950 > RSP: 002b:00007ffd314c8628 EFLAGS: 00000246 > ORIG_RAX: 0000000000000003 > RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000402950 > RDX: 00000000000000e0 RSI: 00007ffd314c8f00 RDI: 0000000000000003 > RBP: 00007ffd314c8740 R08: 00007ffd314c864c R09: 0000000000000001 > R10: 00007ffd314c8740 R11: 0000000000000246 R12: 00000000006cf4c0 > R13: 00000000006cee40 R14: 0000000000001380 R15: 00007ffd314c8768 > Code: > entry_SYSCALL_64_after_hwframe+0x42/0xb7 > 5e > RIP: 0033:0x4456a7 > 41 > RSP: 002b:00007ffd314c8628 EFLAGS: 00000202 ORIG_RAX: 0000000000000029 > 5f > RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00000000004456a7 > 5d > RDX: 0000000000000006 RSI: 0000000000000001 RDI: 0000000000000002 > RBP: 00007ffd314c8740 R08: 0000000000000000 R09: 0000000000000001 > c3 > R10: 0000000000000006 R11: 0000000000000202 R12: 0000000000000003 > e8 > R13: 0000000000000003 R14: 0000000000006cc2 R15: 00007ffd314c8768 > 0a 0b be fe 80 3d 20 c9 84 05 00 75 1a e8 fc 0a be fe 48 c7 c7 e0 78 e5 86 > c6 05 0b c9 84 05 01 e8 a9 16 8e fe <0f> 0b 31 db eb a3 e8 de 0a be fe 83 fb > ff 0f 85 63 ff ff ff 31 > ---[ end trace dd327356f543ce46 ]--- > Dumping ftrace buffer: > (ftrace buffer empty) > Kernel Offset: disabled > Rebooting in 86400 seconds.. > > > --- > This bug is generated by a dumb bot. It may contain errors. > See https://goo.gl/tpsmEJ for details. > Direct all questions to syzkal...@googlegroups.com. > > syzbot will keep track of this bug report. > If you forgot to add the Reported-by tag, once the fix for this bug is > merged > into any tree, please reply to this email with: > #syz fix: exact-commit-title
Broken error handling when mounting rpc_pipefs is messing things up. Fixed by patch in vfs/for-linus: #syz fix: rpc_pipefs: deal with early sget() failures - Eric