bisecting fixing commit since b8776f14a47046796fe078c4a2e691f58e00ae06 building syzkaller on 2bd9619f762176527aaf28fb26e4a08b614b55df testing commit b8776f14a47046796fe078c4a2e691f58e00ae06 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1 kernel signature: b9f2b6414b55439f6ea6cd7a9df45e3d6f4908d197173aa2e48d08010fabdc8c all runs: crashed: general protection fault in fq_codel_enqueue testing current HEAD 5aa1959d18003472cc741dc490c3335c5bd804e2 testing commit 5aa1959d18003472cc741dc490c3335c5bd804e2 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1 kernel signature: 157a3f5aa2b8520cbce9fffc20d8ccc9929fc3503979f188a6094f697e107a34 all runs: crashed: general protection fault in fq_codel_enqueue revisions tested: 2, total time: 26m7.92406033s (build: 18m31.310742194s, test: 6m43.291414336s) the crash still happens on HEAD commit msg: Merge branch 'ionic-fixes' crash: general protection fault in fq_codel_enqueue general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 1 PID: 10195 Comm: syz-executor.3 Not tainted 5.14.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:dequeue_head net/sched/sch_fq_codel.c:120 [inline] RIP: 0010:fq_codel_drop net/sched/sch_fq_codel.c:168 [inline] RIP: 0010:fq_codel_enqueue+0x6e9/0x1020 net/sched/sch_fq_codel.c:230 Code: f9 49 89 d2 49 c1 ea 03 4d 01 fa eb 09 44 39 e5 0f 86 ab 00 00 00 41 80 3a 00 0f 85 5c 06 00 00 48 8b 1a 48 89 d8 48 c1 e8 03 <42> 80 3c 38 00 0f 85 02 06 00 00 48 8b 03 48 8d 7b 28 48 89 02 48 RSP: 0018:ffffc9000166f550 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff888042620000 RSI: 0000000000000000 RDI: ffff888028bc22e8 RBP: 0000000000000040 R08: 0000000000000000 R09: fffff520002cdee4 R10: ffffed10084c4000 R11: 0000000000000000 R12: 0000000000000000 R13: ffffc9000166f720 R14: 0000000000000000 R15: dffffc0000000000 FS: 00007f761a206700(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd331d8960 CR3: 0000000023f1d000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: dev_qdisc_enqueue+0x39/0x220 net/core/dev.c:3854 __dev_xmit_skb net/core/dev.c:3938 [inline] __dev_queue_xmit+0x1784/0x2de0 net/core/dev.c:4253 __bpf_tx_skb net/core/filter.c:2113 [inline] __bpf_redirect_no_mac net/core/filter.c:2138 [inline] __bpf_redirect+0x4d9/0xc20 net/core/filter.c:2161 ____bpf_clone_redirect net/core/filter.c:2445 [inline] bpf_clone_redirect+0x275/0x3f0 net/core/filter.c:2417 bpf_prog_cc75667d52cf7bb0+0x56/0x188 bpf_dispatcher_nop_func include/linux/bpf.h:687 [inline] bpf_test_run+0x37c/0x920 net/bpf/test_run.c:117 bpf_prog_test_run_skb+0x96b/0x1bd0 net/bpf/test_run.c:656 bpf_prog_test_run kernel/bpf/syscall.c:3207 [inline] __sys_bpf+0x1bf3/0x3c90 kernel/bpf/syscall.c:4487 __do_sys_bpf kernel/bpf/syscall.c:4573 [inline] __se_sys_bpf kernel/bpf/syscall.c:4571 [inline] __x64_sys_bpf+0x70/0xb0 kernel/bpf/syscall.c:4571 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x465b09 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f761a206188 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000465b09 RDX: 0000000000000048 RSI: 0000000020000140 RDI: 000000000000000a RBP: 00000000004b069f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007ffd2ca5cf9f R14: 00007f761a206300 R15: 0000000000022000 Modules linked in: ---[ end trace 2a5dd145aea2c11f ]--- RIP: 0010:dequeue_head net/sched/sch_fq_codel.c:120 [inline] RIP: 0010:fq_codel_drop net/sched/sch_fq_codel.c:168 [inline] RIP: 0010:fq_codel_enqueue+0x6e9/0x1020 net/sched/sch_fq_codel.c:230 Code: f9 49 89 d2 49 c1 ea 03 4d 01 fa eb 09 44 39 e5 0f 86 ab 00 00 00 41 80 3a 00 0f 85 5c 06 00 00 48 8b 1a 48 89 d8 48 c1 e8 03 <42> 80 3c 38 00 0f 85 02 06 00 00 48 8b 03 48 8d 7b 28 48 89 02 48 RSP: 0018:ffffc9000166f550 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff888042620000 RSI: 0000000000000000 RDI: ffff888028bc22e8 RBP: 0000000000000040 R08: 0000000000000000 R09: fffff520002cdee4 R10: ffffed10084c4000 R11: 0000000000000000 R12: 0000000000000000 R13: ffffc9000166f720 R14: 0000000000000000 R15: dffffc0000000000 FS: 00007f761a206700(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd331d8960 CR3: 0000000023f1d000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400