syzbot


WARNING in refcount_inc (3)

Status: fixed on 2018/08/24 18:06
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+6eaf536fd743f5e119c5@syzkaller.appspotmail.com
Fix commit: 8e04944f0ea8 mm,vmscan: Allow preallocating memory for register_shrinker().
First crash: 2249d, last: 2246d
Discussions (1)
Title Replies (including bot) Last reply
WARNING in refcount_inc (3) 2 (3) 2018/08/23 07:24
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in refcount_inc (2) net C 8 2320d 2349d 0/26 closed as invalid on 2018/01/31 07:27
upstream WARNING in refcount_inc 7 2459d 2467d 3/26 fixed on 2017/10/24 06:54

Sample crash report:
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 0000000000000003 R14: 0000000000001380 R15: 00007fff3b87f548
------------[ cut here ]------------
refcount_t: increment on 0; use-after-free.
------------[ cut here ]------------
WARNING: CPU: 0 PID: 4439 at lib/refcount.c:153 refcount_inc+0x47/0x50 lib/refcount.c:153
refcount_t: underflow; use-after-free.
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 4439 Comm: syzkaller848704 Not tainted 4.16.0-rc6+ #43
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x24d lib/dump_stack.c:53
WARNING: CPU: 1 PID: 4441 at lib/refcount.c:187 refcount_sub_and_test+0x167/0x1b0 lib/refcount.c:187
Modules linked in:
 panic+0x1e4/0x41c kernel/panic.c:183
CPU: 1 PID: 4441 Comm: syzkaller848704 Not tainted 4.16.0-rc6+ #43
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
RSP: 0018:ffff8801b52d7728 EFLAGS: 00010286
RAX: dffffc0000000008 RBX: 0000000000000000 RCX: ffffffff815b423e
RDX: 0000000000000000 RSI: 1ffff10036a5ae95 RDI: 1ffff10036a5ae6a
RBP: ffff8801b52d77b8 R08: 0000000000000000 R09: 0000000000000001
R10: ffff8801b52d7850 R11: 0000000000000000 R12: 1ffff10036a5aee6
 __warn+0x1dc/0x200 kernel/panic.c:547
R13: 00000000ffffffff R14: 0000000000000001 R15: ffff8801ada18144
FS:  0000000001a59880(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000
 report_bug+0x1f4/0x2b0 lib/bug.c:186
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 fixup_bug.part.10+0x37/0x80 arch/x86/kernel/traps.c:178
CR2: 00007fff3b880000 CR3: 00000001adaaf004 CR4: 00000000001606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 fixup_bug arch/x86/kernel/traps.c:247 [inline]
 do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:296
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 refcount_dec_and_test+0x1a/0x20 lib/refcount.c:212
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315
 put_net include/net/net_namespace.h:222 [inline]
 __sk_destruct+0x560/0x920 net/core/sock.c:1592
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:986
RIP: 0010:refcount_inc+0x47/0x50 lib/refcount.c:153
RSP: 0018:ffff8801add3f860 EFLAGS: 00010286
RAX: dffffc0000000008 RBX: ffff8801add320c4 RCX: ffffffff815b423e
RDX: 0000000000000000 RSI: 1ffff10035ba7ebc RDI: 1ffff10035ba7e91
RBP: ffff8801add3f868 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801add3faf8
R13: ffff8801d911aa93 R14: ffff8801add320c0 R15: ffff8801d911ab01
 get_net include/net/net_namespace.h:204 [inline]
 sk_alloc+0x3f9/0x1440 net/core/sock.c:1540
 sk_destruct+0x47/0x80 net/core/sock.c:1601
 __sk_free+0xf1/0x2b0 net/core/sock.c:1612
 sk_free+0x2a/0x40 net/core/sock.c:1623
 sock_put include/net/sock.h:1664 [inline]
 tcp_close+0x967/0x1190 net/ipv4/tcp.c:2329
 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
 inet_create+0x47c/0xf50 net/ipv4/af_inet.c:320
 ____fput+0x15/0x20 fs/file_table.c:243
 task_work_run+0x199/0x270 kernel/task_work.c:113
 __sock_create+0x4d4/0x850 net/socket.c:1285
 sock_create net/socket.c:1325 [inline]
 SYSC_socket net/socket.c:1355 [inline]
 SyS_socket+0xeb/0x1d0 net/socket.c:1335
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x275/0x2f0 arch/x86/entry/common.c:166
 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
 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x402480
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RSP: 002b:00007fff3b87f408 EFLAGS: 00000246
RIP: 0033:0x4451d7
 ORIG_RAX: 0000000000000003
RSP: 002b:00007fff3b87f408 EFLAGS: 00000206 ORIG_RAX: 0000000000000029
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000402480
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00000000004451d7
RDX: 00000000000000e0 RSI: 00007fff3b87fce0 RDI: 0000000000000003
RDX: 0000000000000006 RSI: 0000000000000001 RDI: 0000000000000002
RBP: 00007fff3b87f520 R08: 0000000000000000 R09: 0000000000000001
RBP: 00007fff3b87f520 R08: 00007fff3b87f42c R09: 0000000000000001
R10: 00007fff3b87f520 R11: 0000000000000246 R12: 00000000006cf4c0
R10: 000000000000000a R11: 0000000000000206 R12: 0000000000000003
R13: 0000000000000003 R14: 0000000000006724 R15: 00007fff3b87f548
R13: 00000000006cee40 R14: 0000000000001380 R15: 00007fff3b87f548
Code: 5e 41 5f 5d c3 e8 9a 26 5e fe 80 3d fb 42 d6 05 00 75 1a e8 8c 26 5e fe 48 c7 c7 a0 a7 75 87 c6 05 e6 42 d6 05 01 e8 d9 33 2e fe <0f> 0b 31 db eb a3 e8 6e 26 5e fe 83 fb ff 0f 85 63 ff ff ff 31 
---[ end trace c7b69e3df19fd10a ]---
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/03/31 09:14 bpf-next 7828f20e3779 8fbce0e4 .config console log report syz C ci-upstream-bpf-next-kasan-gce
2018/03/30 20:03 bpf-next 1379ef828a18 8fbce0e4 .config console log report syz C ci-upstream-bpf-next-kasan-gce
2018/03/30 00:15 bpf-next 1379ef828a18 d47f0ed6 .config console log report syz C ci-upstream-bpf-next-kasan-gce
2018/03/29 11:40 bpf-next 22527437e0a0 d47f0ed6 .config console log report syz C ci-upstream-bpf-next-kasan-gce
2018/03/29 11:17 bpf-next 22527437e0a0 d47f0ed6 .config console log report syz C ci-upstream-bpf-next-kasan-gce
2018/04/01 17:27 bpf-next 7828f20e3779 dc889257 .config console log report syz ci-upstream-bpf-next-kasan-gce
2018/03/29 11:10 bpf-next 22527437e0a0 d47f0ed6 .config console log report ci-upstream-bpf-next-kasan-gce
* Struck through repros no longer work on HEAD.