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 run #0: basic kernel testing failed: BUG: program execution failed: executor NUM: failed to write control pipe: write |NUM: broken pipe run #1: crashed: general protection fault in skb_clone run #2: crashed: general protection fault in skb_clone run #3: crashed: general protection fault in skb_clone run #4: crashed: general protection fault in skb_clone run #5: crashed: general protection fault in skb_clone run #6: crashed: general protection fault in skb_clone run #7: crashed: general protection fault in skb_clone run #8: crashed: general protection fault in skb_clone run #9: crashed: general protection fault in skb_clone run #10: crashed: general protection fault in skb_clone run #11: crashed: general protection fault in skb_clone run #12: crashed: general protection fault in skb_clone run #13: crashed: general protection fault in skb_clone run #14: crashed: general protection fault in skb_clone run #15: crashed: general protection fault in skb_clone run #16: crashed: general protection fault in skb_clone run #17: crashed: general protection fault in skb_clone run #18: crashed: general protection fault in skb_clone run #19: crashed: general protection fault in skb_clone testing current HEAD f4bc5bbb5fef3cf421ba3485d6d383c27ec473ed testing commit f4bc5bbb5fef3cf421ba3485d6d383c27ec473ed compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 761c1bba6f2cf282a2e1013af3f71af2e0776a89ff4e22926182a33274742ca8 all runs: crashed: general protection fault in skb_clone revisions tested: 2, total time: 20m19.411607611s (build: 13m4.397018888s, test: 6m29.576241484s) the crash still happens on HEAD commit msg: Merge tag 'nfsd-5.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux crash: general protection fault in skb_clone RSP: 002b:00007fe7c9bcc2c0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fe7c9ca74e0 RCX: 00007fe7c9bdf1ff RDX: 000000000000000e RSI: 0000000020000100 RDI: 00000000000000c8 RBP: 00007fe7c9c746cc R08: 0000000000000000 R09: 0000000000000001 R10: 00007fe7c9bcc087 R11: 0000000000000293 R12: 00007fe7c9ca74ec R13: 00007fe7c9bcc2f0 R14: 00007fe7c9ca74e8 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: 0 PID: 4298 Comm: syz-executor220 Not tainted 5.17.0-rc3-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:1511 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:ffffc900027cf538 EFLAGS: 00010207 RAX: dffffc0000000000 RBX: ffff88807e846f80 RCX: 1ffff11003a06708 RDX: 000000000000000f RSI: 0000000000000a20 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000140 R09: ffffffff8aec0cb3 R10: fffffbfff15d8196 R11: 0000000000000001 R12: 0000000000000a20 R13: dffffc0000000000 R14: 000000000000007e R15: ffffc900027cf5d8 FS: 00007fe7c9bcc700(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe7c9c57510 CR3: 000000006f03c000 CR4: 00000000003506f0 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+0x9fd/0x18b0 net/hsr/hsr_forward.c:620 hsr_handle_frame+0x47b/0x680 net/hsr/hsr_slave.c:69 __netif_receive_skb_core+0x78d/0x2eb0 net/core/dev.c:5245 __netif_receive_skb_one_core+0xaa/0x180 net/core/dev.c:5349 netif_receive_skb_internal net/core/dev.c:5551 [inline] netif_receive_skb+0xec/0x640 net/core/dev.c:5610 tun_rx_batched.isra.0+0x4b5/0x7d0 drivers/net/tun.c:1516 tun_get_user+0x1c7e/0x2e00 drivers/net/tun.c:1963 tun_chr_write_iter+0xb9/0x160 drivers/net/tun.c:1993 call_write_iter include/linux/fs.h:2074 [inline] new_sync_write+0x368/0x600 fs/read_write.c:503 vfs_write+0x609/0x900 fs/read_write.c:590 ksys_write+0xf4/0x1d0 fs/read_write.c:643 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: 0033:0x7fe7c9bdf1ff 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:00007fe7c9bcc2c0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fe7c9ca74e0 RCX: 00007fe7c9bdf1ff RDX: 000000000000000e RSI: 0000000020000100 RDI: 00000000000000c8 RBP: 00007fe7c9c746cc R08: 0000000000000000 R09: 0000000000000001 R10: 00007fe7c9bcc087 R11: 0000000000000293 R12: 00007fe7c9ca74ec R13: 00007fe7c9bcc2f0 R14: 00007fe7c9ca74e8 R15: 0000000000000001 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:skb_clone+0xdf/0x300 net/core/skbuff.c:1511 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:ffffc900027cf538 EFLAGS: 00010207 RAX: dffffc0000000000 RBX: ffff88807e846f80 RCX: 1ffff11003a06708 RDX: 000000000000000f RSI: 0000000000000a20 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000140 R09: ffffffff8aec0cb3 R10: fffffbfff15d8196 R11: 0000000000000001 R12: 0000000000000a20 R13: dffffc0000000000 R14: 000000000000007e R15: ffffc900027cf5d8 FS: 00007fe7c9bcc700(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe7c9c57510 CR3: 000000006f03c000 CR4: 00000000003506f0 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