bisecting fixing commit since e132c8d7b58d8dc2c1888f5768454550d1f3ea7b
building syzkaller on 426631ddb41a12ad156d0254fea375a9dfa607fc
testing commit e132c8d7b58d8dc2c1888f5768454550d1f3ea7b with gcc (GCC) 8.1.0
kernel signature: f0f74f4e3cf492b528bdc639e28c85812b4da5bf17d76d9b72d790fba8ae053c
all runs: crashed: WARNING in rds_message_alloc_sgs
testing current HEAD 12cd844a39ed16aa183a820a54fe6f9a0bb4cd14
testing commit 12cd844a39ed16aa183a820a54fe6f9a0bb4cd14 with gcc (GCC) 8.1.0
kernel signature: 94f5cb52c7f948091f9c623ed7b95992051fbf2d0cc5ee90427e726b5c87d028
all runs: crashed: WARNING in rds_message_alloc_sgs
revisions tested: 2, total time: 33m26.413621323s (build: 17m13.343286251s, test: 15m19.825397172s)
the crash still happens on HEAD
commit msg: Linux 4.14.173
crash: WARNING in rds_message_alloc_sgs
rdma_op ffff888091654618 conn xmit_rdma           (null)
rdma_op ffff888091654618 conn xmit_rdma           (null)
------------[ cut here ]------------
WARNING: CPU: 0 PID: 28346 at net/rds/message.c:227 rds_message_alloc_sgs+0xcc/0x110 net/rds/message.c:238
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 28346 Comm: syz-executor.5 Not tainted 4.14.173-syzkaller #0
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+0xf7/0x13b lib/dump_stack.c:58
 panic+0x1b0/0x358 kernel/panic.c:183
 __warn.cold.8+0x25/0x2c kernel/panic.c:547
 report_bug+0x1a4/0x1f3 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:177 [inline]
 do_error_trap+0x1bd/0x310 arch/x86/kernel/traps.c:295
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:963
RIP: 0010:rds_message_alloc_sgs+0xcc/0x110 net/rds/message.c:227
RSP: 0018:ffff888076e87798 EFLAGS: 00010202
RAX: 0000000000000008 RBX: ffff888091bf44c0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000088 RDI: ffff888091bf4634
RBP: ffff888076e877c0 R08: ffff888076e874e8 R09: ffff8880a6fdc800
R10: ffff888091bf44c0 R11: 00000000da79fefb R12: 0000000000000000
R13: 0000000000000088 R14: ffff888091bf4630 R15: 0000000000000088
 rds_cmsg_rdma_args+0x62a/0x15c0 net/rds/rdma.c:621
 rds_cmsg_send net/rds/send.c:943 [inline]
 rds_sendmsg+0xcad/0x2210 net/rds/send.c:1132
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0xf0 net/socket.c:656
 ___sys_sendmsg+0x625/0x920 net/socket.c:2062
 __sys_sendmsg+0xc1/0x140 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0xd/0x20 net/socket.c:2103
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459a59
RSP: 002b:00007f20133a2c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459a59
RDX: 0000000000000000 RSI: 0000000020001600 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f20133a36d4
R13: 00000000004c7c0f R14: 00000000004dd9b0 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..