bisecting fixing commit since bfdef05c8da46b022172695aa493cff7ac667a4b building syzkaller on 6acc789ad3f6c04319764f414ebb1a08e6145332 testing commit bfdef05c8da46b022172695aa493cff7ac667a4b compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: f8de5275c4d3a4e02c2015e394bf00a04a56814f77fc47216bc141234adef630 run #0: crashed: general protection fault in rds_ib_get_mr run #1: crashed: general protection fault in rds_ib_get_mr run #2: crashed: unregister_netdevice: waiting for DEV to become free run #3: crashed: unregister_netdevice: waiting for DEV to become free run #4: crashed: general protection fault in rds_ib_get_mr run #5: crashed: unregister_netdevice: waiting for DEV to become free run #6: crashed: unregister_netdevice: waiting for DEV to become free run #7: crashed: unregister_netdevice: waiting for DEV to become free run #8: crashed: general protection fault in rds_ib_get_mr run #9: crashed: unregister_netdevice: waiting for DEV to become free run #10: crashed: general protection fault in rds_ib_get_mr run #11: crashed: general protection fault in rds_ib_get_mr run #12: crashed: general protection fault in rds_ib_get_mr run #13: crashed: unregister_netdevice: waiting for DEV to become free run #14: crashed: general protection fault in rds_ib_get_mr run #15: crashed: unregister_netdevice: waiting for DEV to become free run #16: crashed: unregister_netdevice: waiting for DEV to become free run #17: crashed: unregister_netdevice: waiting for DEV to become free run #18: crashed: unregister_netdevice: waiting for DEV to become free run #19: crashed: unregister_netdevice: waiting for DEV to become free testing current HEAD b86ee2b7ae42b6b37a918b66236608e2cc325f59 testing commit b86ee2b7ae42b6b37a918b66236608e2cc325f59 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 0221c990324c77303ac693e2d8cd669050420bfdd79c984a61fdb02efee93c22 run #0: crashed: unregister_netdevice: waiting for DEV to become free run #1: crashed: general protection fault in rds_ib_get_mr run #2: crashed: unregister_netdevice: waiting for DEV to become free run #3: crashed: general protection fault in rds_ib_get_mr run #4: crashed: unregister_netdevice: waiting for DEV to become free run #5: crashed: unregister_netdevice: waiting for DEV to become free run #6: crashed: general protection fault in rds_ib_get_mr run #7: crashed: unregister_netdevice: waiting for DEV to become free run #8: crashed: general protection fault in rds_ib_get_mr run #9: crashed: general protection fault in rds_ib_get_mr revisions tested: 2, total time: 26m14.961799746s (build: 18m50.712719089s, test: 6m56.890245264s) the crash still happens on HEAD commit msg: Linux 4.14.264 crash: general protection fault in rds_ib_get_mr kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN Modules linked in: CPU: 1 PID: 8315 Comm: syz-executor029 Not tainted 4.14.264-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff888092d14240 task.stack: ffff888093bd8000 RIP: 0010:rds_ib_get_mr+0x58/0x210 net/rds/ib_rdma.c:543 RSP: 0018:ffff888093bdfaf0 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 000000000000000d RDX: ffff8880af02e040 RSI: 0000000000000001 RDI: 0000000000000068 RBP: ffff888093bdfb20 R08: 0000000000000001 R09: ffff888094ce7600 R10: ffffed101299cec4 R11: ffff888094ce7627 R12: ffff888094ce7600 R13: 0000000000000001 R14: ffff8880af02e040 R15: ffff8880aada049c FS: 00007f3bf55e9700(0000) GS:ffff8880ba700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3bf55e9718 CR3: 00000000aaeb3000 CR4: 00000000003406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __rds_rdma_map+0x8ff/0xf40 net/rds/rdma.c:271 rds_get_mr_for_dest+0xbc/0x100 net/rds/rdma.c:357 rds_setsockopt+0x3ce/0x7e0 net/rds/af_rds.c:347 SYSC_setsockopt net/socket.c:1865 [inline] SyS_setsockopt+0x130/0x1f0 net/socket.c:1844 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f3bf5657ce9 RSP: 002b:00007f3bf55e9318 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007f3bf56e03f8 RCX: 00007f3bf5657ce9 RDX: 0000000000000007 RSI: 0000000000000114 RDI: 0000000000000003 RBP: 00007f3bf56e03f0 R08: 00000000000000a0 R09: 0000000000000000 R10: 0000000020000140 R11: 0000000000000246 R12: 00007f3bf56e03fc R13: 00007ffcf2ff243f R14: 00007f3bf55e9400 R15: 0000000000022000 Code: 08 48 c1 e9 03 80 3c 01 00 0f 85 bb 01 00 00 48 8b 9a c0 04 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 68 48 89 f9 48 c1 e9 03 <80> 3c 01 00 0f 85 83 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 RIP: rds_ib_get_mr+0x58/0x210 net/rds/ib_rdma.c:543 RSP: ffff888093bdfaf0 ---[ end trace 1a25fff7d35d387e ]--- ---------------- Code disassembly (best guess): 0: 08 48 c1 or %cl,-0x3f(%rax) 3: e9 03 80 3c 01 jmpq 0x13c800b 8: 00 0f add %cl,(%rdi) a: 85 bb 01 00 00 48 test %edi,0x48000001(%rbx) 10: 8b 9a c0 04 00 00 mov 0x4c0(%rdx),%ebx 16: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 1d: fc ff df 20: 48 8d 7b 68 lea 0x68(%rbx),%rdi 24: 48 89 f9 mov %rdi,%rcx 27: 48 c1 e9 03 shr $0x3,%rcx * 2b: 80 3c 01 00 cmpb $0x0,(%rcx,%rax,1) <-- trapping instruction 2f: 0f 85 83 01 00 00 jne 0x1b8 35: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 3c: fc ff df 3f: 48 rex.W