bisecting fixing commit since a03957ab0fd5d7d03b512a72ab9106a1749f556e building syzkaller on 1bfa09b9672821334a7ed926244ebc39910b84f4 testing commit a03957ab0fd5d7d03b512a72ab9106a1749f556e with gcc (GCC) 8.1.0 kernel signature: 3f28ecacc725d32d2f29e79fea1859f6e7465851 run #0: crashed: general protection fault in flex_array_get run #1: crashed: general protection fault in flex_array_get run #2: crashed: general protection fault in flex_array_get run #3: crashed: general protection fault in flex_array_get run #4: crashed: general protection fault in corrupted run #5: crashed: general protection fault in flex_array_get run #6: crashed: general protection fault in flex_array_get run #7: crashed: general protection fault in flex_array_get run #8: crashed: general protection fault in corrupted run #9: crashed: general protection fault in flex_array_get testing current HEAD 672481c2deffb371d8a7dfdc009e44c09864a869 testing commit 672481c2deffb371d8a7dfdc009e44c09864a869 with gcc (GCC) 8.1.0 kernel signature: cf0eccceee369582946c3804399f6e2373e9aff7 run #0: crashed: general protection fault in flex_array_get run #1: crashed: general protection fault in corrupted run #2: crashed: general protection fault in flex_array_get run #3: crashed: general protection fault in flex_array_get run #4: crashed: general protection fault in flex_array_get run #5: crashed: general protection fault in flex_array_get run #6: crashed: general protection fault in flex_array_get run #7: crashed: general protection fault in flex_array_get run #8: crashed: general protection fault in flex_array_get run #9: crashed: general protection fault in flex_array_get revisions tested: 2, total time: 24m31.197435525s (build: 16m47.341907804s, test: 6m59.534893467s) the crash still happens on HEAD commit msg: Linux 4.19.91 crash: general protection fault in flex_array_get kasan: CONFIG_KASAN_INLINE enabled __sys_sendmsg+0xd9/0x180 net/socket.c:2153 kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN __do_sys_sendmsg net/socket.c:2162 [inline] __se_sys_sendmsg net/socket.c:2160 [inline] __x64_sys_sendmsg+0x73/0xb0 net/socket.c:2160 CPU: 1 PID: 7268 Comm: syz-executor.1 Not tainted 4.19.91-syzkaller #0 do_syscall_64+0xd6/0x4e0 arch/x86/entry/common.c:293 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0010:flex_array_get+0x23/0x240 lib/flex_array.c:320 RIP: 0033:0x458da9 Code: 90 90 90 90 90 90 90 48 b8 00 00 00 00 00 fc ff df 55 48 89 fa 48 89 e5 48 c1 ea 03 41 56 41 55 41 54 53 48 89 fb 48 83 ec 10 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 8d 01 00 00 44 8b 33 45 85 f6 Code: ad b8 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 b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 0018:ffff88807dc0f5a0 EFLAGS: 00010286 RSP: 002b:00007f38f0864c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff11011eb4946 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f38f0864c90 RCX: 0000000000458da9 RBP: ffff88807dc0f5d0 R08: ffff88807dc0f908 R09: ffffed1015d64732 RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000003 R10: ffffed1015d64732 R11: 0000000000000000 R12: ffff88808a2fca80 RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000 R13: ffff888075f02484 R14: ffff8880838b6d00 R15: 1ffff1101145fa39 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f38f08656d4 R13: 00000000004c5ff5 R14: 00000000004da7d8 R15: 0000000000000005 FS: 00007f3392869700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 kasan: GPF could be caused by NULL-ptr deref or user memory access CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000024bb570 CR3: 00000000a8bbf000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: sctp_stream_out include/net/sctp/structs.h:1474 [inline] sctp_sched_dequeue_done+0x1d8/0x300 net/sctp/stream_sched.c:255 __sctp_outq_teardown+0x660/0xc30 net/sctp/outqueue.c:267 sctp_outq_free+0x9/0x10 net/sctp/outqueue.c:291 sctp_association_free+0x1d5/0x711 net/sctp/associola.c:361 sctp_cmd_delete_tcb net/sctp/sm_sideeffect.c:944 [inline] sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1332 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1199 [inline] sctp_do_sm+0x91e/0x52d0 net/sctp/sm_sideeffect.c:1170 sctp_primitive_SHUTDOWN+0x7c/0xc0 net/sctp/primitive.c:104 sctp_close+0x354/0x750 net/sctp/socket.c:1545 inet_release+0xde/0x1c0 net/ipv4/af_inet.c:428 __sock_release+0xc7/0x2a0 net/socket.c:579 sock_close+0x10/0x20 net/socket.c:1140 __fput+0x24c/0x7f0 fs/file_table.c:278 ____fput+0x9/0x10 fs/file_table.c:309 task_work_run+0x10e/0x190 kernel/task_work.c:113 get_signal+0x139f/0x1a00 kernel/signal.c:2389 do_signal+0x87/0x1960 arch/x86/kernel/signal.c:821 exit_to_usermode_loop+0x114/0x200 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x419/0x4e0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458da9 Code: ad b8 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 b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f3392868c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: 000000000001fff8 RBX: 00007f3392868c90 RCX: 0000000000458da9 RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000003 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f33928696d4 R13: 00000000004c5ff5 R14: 00000000004da7d8 R15: 0000000000000005 Modules linked in: general protection fault: 0000 [#2] PREEMPT SMP KASAN CPU: 1 PID: 7273 Comm: syz-executor.3 Tainted: G D 4.19.91-syzkaller #0 CPU: 0 PID: 7252 Comm: syz-executor.2 Tainted: G D 4.19.91-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: RIP: 0010:flex_array_get+0x23/0x240 lib/flex_array.c:320 __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x123/0x177 lib/dump_stack.c:118 Code: 90 90 90 90 90 90 90 48 b8 00 00 00 00 00 fc ff df 55 48 89 fa 48 89 e5 48 c1 ea 03 41 56 41 55 41 54 53 48 89 fb 48 83 ec 10 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 8d 01 00 00 44 8b 33 45 85 f6 fail_dump lib/fault-inject.c:51 [inline] should_fail.cold.4+0x5/0x13 lib/fault-inject.c:149 RSP: 0018:ffff88808bf775a0 EFLAGS: 00010286 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff11012715996 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88808bf775d0 R08: ffff88808bf77908 R09: ffffed1015d44732 __should_failslab+0xba/0xf0 mm/failslab.c:32 R10: ffffed1015d44732 R11: 0000000000000000 R12: ffff88808bc72180 should_failslab+0x9/0x14 mm/slab_common.c:1557 R13: ffff888075c82204 R14: ffff88807d560800 R15: 1ffff1101178e519 slab_pre_alloc_hook mm/slab.h:424 [inline] slab_alloc_node mm/slab.c:3304 [inline] kmem_cache_alloc_node+0x56/0x730 mm/slab.c:3647 FS: 00007f01b73f3700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000625208 CR3: 0000000091699000 CR4: 00000000001406f0 __alloc_skb+0xa7/0x580 net/core/skbuff.c:193 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: sctp_stream_out include/net/sctp/structs.h:1474 [inline] sctp_sched_dequeue_done+0x1d8/0x300 net/sctp/stream_sched.c:255 alloc_skb include/linux/skbuff.h:995 [inline] _sctp_make_chunk+0x3f/0x260 net/sctp/sm_make_chunk.c:1407 __sctp_outq_teardown+0x660/0xc30 net/sctp/outqueue.c:267 sctp_make_control net/sctp/sm_make_chunk.c:1454 [inline] sctp_make_cookie_echo+0x85/0x160 net/sctp/sm_make_chunk.c:591 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1395 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1199 [inline] sctp_do_sm+0x2849/0x52d0 net/sctp/sm_sideeffect.c:1170 sctp_outq_free+0x9/0x10 net/sctp/outqueue.c:291 sctp_association_free+0x1d5/0x711 net/sctp/associola.c:361 sctp_cmd_delete_tcb net/sctp/sm_sideeffect.c:944 [inline] sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1332 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1199 [inline] sctp_do_sm+0x91e/0x52d0 net/sctp/sm_sideeffect.c:1170 sctp_assoc_bh_rcv+0x27f/0x5c0 net/sctp/associola.c:1073 sctp_inq_push+0x1aa/0x240 net/sctp/inqueue.c:95 sctp_backlog_rcv+0x153/0xb90 net/sctp/input.c:351 sctp_primitive_SHUTDOWN+0x7c/0xc0 net/sctp/primitive.c:104 sctp_close+0x354/0x750 net/sctp/socket.c:1545 inet_release+0xde/0x1c0 net/ipv4/af_inet.c:428 sk_backlog_rcv include/net/sock.h:941 [inline] __release_sock+0x10c/0x360 net/core/sock.c:2339 __sock_release+0xc7/0x2a0 net/socket.c:579 release_sock+0x4f/0x180 net/core/sock.c:2855 sock_close+0x10/0x20 net/socket.c:1140 sctp_wait_for_connect+0x22c/0x4c0 net/sctp/socket.c:8617 __fput+0x24c/0x7f0 fs/file_table.c:278 ____fput+0x9/0x10 fs/file_table.c:309 task_work_run+0x10e/0x190 kernel/task_work.c:113 get_signal+0x139f/0x1a00 kernel/signal.c:2389 do_signal+0x87/0x1960 arch/x86/kernel/signal.c:821 sctp_sendmsg_to_asoc+0x10e8/0x15d0 net/sctp/socket.c:1971 sctp_sendmsg+0xd4f/0x17e0 net/sctp/socket.c:2117 inet_sendmsg+0x10d/0x450 net/ipv4/af_inet.c:798 exit_to_usermode_loop+0x114/0x200 arch/x86/entry/common.c:163 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xb7/0xf0 net/socket.c:632 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x419/0x4e0 arch/x86/entry/common.c:296 ___sys_sendmsg+0x649/0x950 net/socket.c:2115 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458da9 Code: ad b8 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 b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f01b73f2c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: 000000000001fff8 RBX: 00007f01b73f2c90 RCX: 0000000000458da9 RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000003 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f01b73f36d4 R13: 00000000004c5ff5 R14: 00000000004da7d8 R15: 0000000000000005 Modules linked in: __sys_sendmsg+0xd9/0x180 net/socket.c:2153 __do_sys_sendmsg net/socket.c:2162 [inline] __se_sys_sendmsg net/socket.c:2160 [inline] __x64_sys_sendmsg+0x73/0xb0 net/socket.c:2160 do_syscall_64+0xd6/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458da9 Code: ad b8 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 b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f29e08c9c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f29e08c9c90 RCX: 0000000000458da9 RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000003 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f29e08ca6d4 R13: 00000000004c5ff5 R14: 00000000004da7d8 R15: 0000000000000005 CPU: 0 PID: 7265 Comm: syz-executor.4 Tainted: G D 4.19.91-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ---[ end trace 36dc3cc8ae13582f ]--- Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x123/0x177 lib/dump_stack.c:118 fail_dump lib/fault-inject.c:51 [inline] should_fail.cold.4+0x5/0x13 lib/fault-inject.c:149 RIP: 0010:flex_array_get+0x23/0x240 lib/flex_array.c:320 Code: 90 90 90 90 90 90 90 48 b8 00 00 00 00 00 fc ff df 55 48 89 fa 48 89 e5 48 c1 ea 03 41 56 41 55 41 54 53 48 89 fb 48 83 ec 10 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 8d 01 00 00 44 8b 33 45 85 f6 __should_failslab+0xba/0xf0 mm/failslab.c:32 RSP: 0018:ffff88807dc0f5a0 EFLAGS: 00010286 should_failslab+0x9/0x14 mm/slab_common.c:1557 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff11011eb4946 slab_pre_alloc_hook mm/slab.h:424 [inline] slab_alloc_node mm/slab.c:3304 [inline] kmem_cache_alloc_node+0x56/0x730 mm/slab.c:3647 FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 __alloc_skb+0xa7/0x580 net/core/skbuff.c:193 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88807dc0f5d0 R08: ffff88807dc0f908 R09: ffffed1015d64732 R10: ffffed1015d64732 R11: 0000000000000000 R12: ffff88808a2fca80 alloc_skb include/linux/skbuff.h:995 [inline] _sctp_make_chunk+0x3f/0x260 net/sctp/sm_make_chunk.c:1407 R13: ffff888075f02484 R14: ffff8880838b6d00 R15: 1ffff1101145fa39 sctp_make_control net/sctp/sm_make_chunk.c:1454 [inline] sctp_make_cookie_echo+0x85/0x160 net/sctp/sm_make_chunk.c:591 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1395 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1199 [inline] sctp_do_sm+0x2849/0x52d0 net/sctp/sm_sideeffect.c:1170 FS: 00007f3392869700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000040 CR3: 00000000a8bbf000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 sctp_assoc_bh_rcv+0x27f/0x5c0 net/sctp/associola.c:1073 sctp_inq_push+0x1aa/0x240 net/sctp/inqueue.c:95 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 sctp_backlog_rcv+0x153/0xb90 net/sctp/input.c:351