bisecting fixing commit since fd786fb1d2cad70b9aaba8c73872cbf63262bd58
building syzkaller on 3334d684ce742ce58ad66b7dcb7a6d4da5185796
testing commit fd786fb1d2cad70b9aaba8c73872cbf63262bd58 with gcc (GCC) 8.1.0
kernel signature: da845694b6db8d2e36a0e9482e8830324ad23556906e57323716f12f18e83c65
run #0: crashed: WARNING: refcount bug in sk_alloc
run #1: crashed: WARNING: refcount bug in sk_alloc
run #2: crashed: WARNING: refcount bug in sk_alloc
run #3: crashed: WARNING: refcount bug in sk_alloc
run #4: crashed: WARNING: refcount bug in sk_alloc
run #5: crashed: WARNING: refcount bug in sk_alloc
run #6: crashed: WARNING: refcount bug in sk_alloc
run #7: crashed: WARNING: refcount bug in sk_alloc
run #8: crashed: WARNING: refcount bug in __sk_destruct
run #9: crashed: WARNING: refcount bug in sk_alloc
testing current HEAD 63bef48fd6c9d3f1ba4f0e23b4da1e007db6a3c0
testing commit 63bef48fd6c9d3f1ba4f0e23b4da1e007db6a3c0 with gcc (GCC) 8.1.0
kernel signature: 9d9d6ae5363814927bc1d340304303ceb4e1b45608c35bd9bd4f79c41699d22b
all runs: crashed: WARNING: refcount bug in sk_alloc
revisions tested: 2, total time: 20m17.330330313s (build: 12m14.311082913s, test: 7m6.172652699s)
the crash still happens on HEAD
commit msg: Merge branch 'akpm' (patches from Andrew)
crash: WARNING: refcount bug in sk_alloc
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 0 PID: 8751 at lib/refcount.c:25 refcount_warn_saturate+0xe7/0x140 lib/refcount.c:25
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 8751 Comm: syz-executor.1 Not tainted 5.6.0-syzkaller #0
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+0x12d/0x187 lib/dump_stack.c:118
 panic+0x22a/0x4e3 kernel/panic.c:221
 __warn.cold.10+0x25/0x2a kernel/panic.c:582
 report_bug+0x1b0/0x270 lib/bug.c:195
 fixup_bug arch/x86/kernel/traps.c:175 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267
 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:286
 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027
RIP: 0010:refcount_warn_saturate+0xe7/0x140 lib/refcount.c:25
Code: e2 80 79 06 01 e8 81 15 e1 fd 0f 0b eb 9b 80 3d d1 80 79 06 00 75 92 48 c7 c7 60 03 ee 87 c6 05 c1 80 79 06 01 e8 61 15 e1 fd <0f> 0b e9 78 ff ff ff 80 3d ab 80 79 06 00 0f 85 6b ff ff ff 48 c7
RSP: 0018:ffffc90005737ce8 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff888096e4a1c4 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff8abd64e0
RBP: ffffc90005737cf8 R08: ffffed1015d466a9 R09: ffffed1015d466a9
R10: ffff8880aea33547 R11: ffffed1015d466a8 R12: 0000000000000002
R13: 0000000000000001 R14: 0000000000000010 R15: ffff888093894000
 refcount_add include/linux/refcount.h:191 [inline]
 refcount_inc include/linux/refcount.h:228 [inline]
 get_net include/net/net_namespace.h:246 [inline]
 sk_alloc+0xc86/0xdc0 net/core/sock.c:1670
 __netlink_create+0x5c/0x2f0 net/netlink/af_netlink.c:629
 netlink_create+0x2f9/0x540 net/netlink/af_netlink.c:692
 __sock_create+0x258/0x530 net/socket.c:1433
 sock_create net/socket.c:1484 [inline]
 __sys_socket+0xd7/0x1c0 net/socket.c:1526
 __do_sys_socket net/socket.c:1535 [inline]
 __se_sys_socket net/socket.c:1533 [inline]
 __x64_sys_socket+0x6e/0xb0 net/socket.c:1533
 do_syscall_64+0xca/0x630 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45b349
Code: ad b6 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fda73e3ac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 00007fda73e3b6d4 RCX: 000000000045b349
RDX: 0000000000000000 RSI: 0000000000080002 RDI: 0000000000000010
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000b03 R14: 00000000004cbf40 R15: 000000000075bf2c
Kernel Offset: disabled
Rebooting in 86400 seconds..