bisecting fixing commit since afae3cc2da100ead3cd6ef4bb1fb8bc9d4b817c5
building syzkaller on c090b4da255257841173fb4eb18c19d69b293180
testing commit afae3cc2da100ead3cd6ef4bb1fb8bc9d4b817c5 with gcc (GCC) 8.1.0
kernel signature: 0b86b6cef5cab9b83bcecab25d3f3d42a147824902b506955108d93a634630bf
run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in reuseport_add_sock
run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in reuseport_add_sock
run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in sctp_bind_addrs_check
run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in reuseport_add_sock
run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in reuseport_add_sock
run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in reuseport_add_sock
run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in reuseport_add_sock
run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in reuseport_add_sock
run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in reuseport_add_sock
run #9: crashed: BUG: unable to handle kernel NULL pointer dereference in reuseport_add_sock
testing current HEAD 833d22f2f922bbee6430e558417af060db6bbe9c
testing commit 833d22f2f922bbee6430e558417af060db6bbe9c with gcc (GCC) 8.1.0
kernel signature: fc5343b7ce26896f0e31dca7fda9c2492b9b4a7b5ccde705e94b381466557fff
all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in reuseport_add_sock
revisions tested: 2, total time: 17m42.880377544s (build: 9m8.406217887s, test: 7m58.482421543s)
the crash still happens on HEAD
commit msg: Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
crash: BUG: unable to handle kernel NULL pointer dereference in reuseport_add_sock
BUG: kernel NULL pointer dereference, address: 0000000000000012
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 11efba067 P4D 11efba067 PUD 11fadd067 PMD 0 
Oops: 0000 [#1] PREEMPT SMP
CPU: 1 PID: 15569 Comm: syz-executor.2 Not tainted 5.11.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:reuseport_add_sock+0x76/0x280 net/core/sock_reuseport.c:161
Code: 00 48 8b 9b 98 04 00 00 e8 e7 11 af 00 85 c0 75 66 4d 8b ac 24 98 04 00 00 4d 85 ed 74 0c 66 41 83 7d 12 01 0f 85 e8 01 00 00 <0f> b7 43 12 66 3b 43 10 0f 84 92 00 00 00 4c 89 64 c3 28 66 83 43
RSP: 0018:ffffc900013d3e18 EFLAGS: 00010246
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 00000000ffffffff
RDX: 0000000000000001 RSI: ffffffff848fa474 RDI: ffffffff84a02a86
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000001 R12: ffff888144b6e800
R13: 0000000000000000 R14: ffff88810c2dd600 R15: 0000000000000000
FS:  00007f98c2c8b700(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000012 CR3: 000000011f3ca000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __sctp_hash_endpoint net/sctp/input.c:750 [inline]
 sctp_hash_endpoint+0x172/0x180 net/sctp/input.c:778
 sctp_listen_start net/sctp/socket.c:8390 [inline]
 sctp_inet_listen+0x16b/0x210 net/sctp/socket.c:8445
 __sys_listen+0x5d/0xa0 net/socket.c:1669
 __do_sys_listen net/socket.c:1678 [inline]
 __se_sys_listen net/socket.c:1676 [inline]
 __x64_sys_listen+0xd/0x10 net/socket.c:1676
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45e159
Code: 0d b4 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 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f98c2c8ac68 EFLAGS: 00000246 ORIG_RAX: 0000000000000032
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 000000000045e159
RDX: 0000000000000000 RSI: 0000000000000050 RDI: 0000000000000004
RBP: 000000000119bfb8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bf8c
R13: 00007ffe43a8975f R14: 00007f98c2c8b9c0 R15: 000000000119bf8c
Modules linked in:
CR2: 0000000000000012
---[ end trace d548a1a147c721c1 ]---
RIP: 0010:reuseport_add_sock+0x76/0x280 net/core/sock_reuseport.c:161
Code: 00 48 8b 9b 98 04 00 00 e8 e7 11 af 00 85 c0 75 66 4d 8b ac 24 98 04 00 00 4d 85 ed 74 0c 66 41 83 7d 12 01 0f 85 e8 01 00 00 <0f> b7 43 12 66 3b 43 10 0f 84 92 00 00 00 4c 89 64 c3 28 66 83 43
RSP: 0018:ffffc900013d3e18 EFLAGS: 00010246
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 00000000ffffffff
RDX: 0000000000000001 RSI: ffffffff848fa474 RDI: ffffffff84a02a86
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000001 R12: ffff888144b6e800
R13: 0000000000000000 R14: ffff88810c2dd600 R15: 0000000000000000
FS:  00007f98c2c8b700(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000012 CR3: 000000011f3ca000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400