bisecting fixing commit since 6f513529296fd4f696afb4354c46508abe646541 building syzkaller on 49ca1f59e37fcf63dc38a6bd2b60fcc47a0a708e testing commit 6f513529296fd4f696afb4354c46508abe646541 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: a53ad9d52b393896d2f0b6b838be9a7d0ed08da33fc7fd1c1d8a0e6c1a0c55f7 all runs: crashed: general protection fault in skb_clone testing current HEAD ce522ba9ef7e2d9fb22a39eb3371c0c64e2a433e testing commit ce522ba9ef7e2d9fb22a39eb3371c0c64e2a433e compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 882b7cae9128fa3c907bb8d229c845dad26463ec16bb3f2283e8fd4dc70b9ea8 all runs: crashed: general protection fault in skb_clone revisions tested: 2, total time: 19m31.335280258s (build: 11m56.299947727s, test: 6m49.11229192s) the crash still happens on HEAD commit msg: Linux 5.18-rc2 crash: general protection fault in skb_clone RDX: 000000000000000e RSI: 0000000020000100 RDI: 00000000000000c8 RBP: 00007fd326c716cc R08: 0000000000000000 R09: 0000000000000001 R10: 00007fd326bc9087 R11: 0000000000000293 R12: 00007fd326ca44ec R13: 00007fd326bc92f0 R14: 00007fd326ca44e8 R15: 0000000000000001 general protection fault, probably for non-canonical address 0xdffffc000000000f: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000078-0x000000000000007f] CPU: 1 PID: 4226 Comm: syz-executor363 Not tainted 5.18.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:skb_clone+0xdf/0x300 net/core/skbuff.c:1512 Code: 02 00 0f 85 fd 01 00 00 48 8b 5b 28 48 85 db 0f 85 ab 00 00 00 4c 8d 75 7e 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 <0f> b6 04 02 4c 89 f2 83 e2 07 38 d0 7f 08 84 c0 0f 85 44 01 00 00 RSP: 0018:ffffc90004ae7518 EFLAGS: 00010207 RAX: dffffc0000000000 RBX: ffff8880736f1580 RCX: 1ffff1100e6d8130 RDX: 000000000000000f RSI: 0000000000000a20 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000140 R09: ffffffff8aec3a13 R10: fffffbfff15d8742 R11: 0000000000000001 R12: 0000000000000a20 R13: ffff8880736f1590 R14: 000000000000007e R15: ffffc90004ae75c8 FS: 00007fd326bc9700(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd326c54510 CR3: 0000000023bea000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: hsr_forward_do net/hsr/hsr_forward.c:461 [inline] hsr_forward_skb+0xa68/0x1ab0 net/hsr/hsr_forward.c:623 hsr_handle_frame+0x47b/0x680 net/hsr/hsr_slave.c:69 __netif_receive_skb_core+0x7f5/0x3170 net/core/dev.c:5297 __netif_receive_skb_one_core+0xaa/0x180 net/core/dev.c:5403 netif_receive_skb_internal net/core/dev.c:5605 [inline] netif_receive_skb+0xec/0x640 net/core/dev.c:5664 tun_rx_batched.isra.0+0x4b5/0x7d0 drivers/net/tun.c:1534 tun_get_user+0x1eb2/0x3490 drivers/net/tun.c:1985 tun_chr_write_iter+0xb3/0x150 drivers/net/tun.c:2015 call_write_iter include/linux/fs.h:2050 [inline] new_sync_write+0x2e0/0x520 fs/read_write.c:504 vfs_write+0x607/0x8f0 fs/read_write.c:591 ksys_write+0xee/0x1c0 fs/read_write.c:644 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0x80 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fd326bdc1ff Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 99 fd ff ff 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 cc fd ff ff 48 RSP: 002b:00007fd326bc92c0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fd326ca44e0 RCX: 00007fd326bdc1ff RDX: 000000000000000e RSI: 0000000020000100 RDI: 00000000000000c8 RBP: 00007fd326c716cc R08: 0000000000000000 R09: 0000000000000001 R10: 00007fd326bc9087 R11: 0000000000000293 R12: 00007fd326ca44ec R13: 00007fd326bc92f0 R14: 00007fd326ca44e8 R15: 0000000000000001 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:skb_clone+0xdf/0x300 net/core/skbuff.c:1512 Code: 02 00 0f 85 fd 01 00 00 48 8b 5b 28 48 85 db 0f 85 ab 00 00 00 4c 8d 75 7e 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 <0f> b6 04 02 4c 89 f2 83 e2 07 38 d0 7f 08 84 c0 0f 85 44 01 00 00 RSP: 0018:ffffc90004ae7518 EFLAGS: 00010207 RAX: dffffc0000000000 RBX: ffff8880736f1580 RCX: 1ffff1100e6d8130 RDX: 000000000000000f RSI: 0000000000000a20 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000140 R09: ffffffff8aec3a13 R10: fffffbfff15d8742 R11: 0000000000000001 R12: 0000000000000a20 R13: ffff8880736f1590 R14: 000000000000007e R15: ffffc90004ae75c8 FS: 00007fd326bc9700(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd326c54510 CR3: 0000000023bea000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 02 00 add (%rax),%al 2: 0f 85 fd 01 00 00 jne 0x205 8: 48 8b 5b 28 mov 0x28(%rbx),%rbx c: 48 85 db test %rbx,%rbx f: 0f 85 ab 00 00 00 jne 0xc0 15: 4c 8d 75 7e lea 0x7e(%rbp),%r14 19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 20: fc ff df 23: 4c 89 f2 mov %r14,%rdx 26: 48 c1 ea 03 shr $0x3,%rdx * 2a: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax <-- trapping instruction 2e: 4c 89 f2 mov %r14,%rdx 31: 83 e2 07 and $0x7,%edx 34: 38 d0 cmp %dl,%al 36: 7f 08 jg 0x40 38: 84 c0 test %al,%al 3a: 0f 85 44 01 00 00 jne 0x184