bisecting fixing commit since 5472f14a37421d1bca3dddf33cabd3bd6dbefbbc building syzkaller on 5d14b1ea9683380c2098648a6b86f95eff7729dd testing commit 5472f14a37421d1bca3dddf33cabd3bd6dbefbbc compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: c9eaf250bba69bd7caadbcac4f3492046c5af985ef16d1d57b68c3b2e5b8da02 all runs: crashed: general protection fault in skb_clone testing current HEAD ed4643521e6af8ab8ed1e467630a85884d2696cf testing commit ed4643521e6af8ab8ed1e467630a85884d2696cf compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 21f9a7c4cd0dfffc9456ea38f4c298599bf69096c16bd167a2a3a41cfa844f6b all runs: crashed: general protection fault in skb_clone revisions tested: 2, total time: 19m36.58290232s (build: 12m30.478717854s, test: 6m32.887274319s) the crash still happens on HEAD commit msg: Merge tag 'arm-dt-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc crash: general protection fault in skb_clone RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007fcce8240d63 RDX: 000000000000000e RSI: 0000000020000100 RDI: 00000000000000c8 RBP: 00007ffc40b60b90 R08: 0000000000000000 R09: 0000000000000001 R10: 00007ffc40b60907 R11: 0000000000000246 R12: 0000000000000003 R13: 00007ffc40b60bb0 R14: 00007ffc40b60ba0 R15: 00007ffc40b60b7c 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: 4158 Comm: syz-executor343 Tainted: G W 5.17.0-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:ffffc90002b9f528 EFLAGS: 00010207 RAX: dffffc0000000000 RBX: ffff88801c69da80 RCX: 1ffff110031624e0 RDX: 000000000000000f RSI: 0000000000000a20 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000140 R09: ffffffff8aec0df3 R10: fffffbfff15d81be R11: 3e4b5341542f3c20 R12: 0000000000000a20 R13: ffff88801c69da90 R14: 000000000000007e R15: ffffc90002b9f5c8 FS: 0000555555dbf300(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcce82e02a4 CR3: 00000000764f1000 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+0x9e6/0x1930 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+0x1dc0/0x30c0 drivers/net/tun.c:1963 tun_chr_write_iter+0xb9/0x160 drivers/net/tun.c:1993 call_write_iter include/linux/fs.h:2081 [inline] new_sync_write+0x368/0x600 fs/read_write.c:504 vfs_write+0x610/0x900 fs/read_write.c:591 ksys_write+0xf4/0x1d0 fs/read_write.c:644 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: 0033:0x7fcce8240d63 Code: e9 0e ec ff ff bf 01 00 00 00 e8 a8 6f 00 00 0f 1f 84 00 00 00 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 55 c3 0f 1f 40 00 48 83 ec 28 48 89 54 24 18 RSP: 002b:00007ffc40b60b68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007fcce8240d63 RDX: 000000000000000e RSI: 0000000020000100 RDI: 00000000000000c8 RBP: 00007ffc40b60b90 R08: 0000000000000000 R09: 0000000000000001 R10: 00007ffc40b60907 R11: 0000000000000246 R12: 0000000000000003 R13: 00007ffc40b60bb0 R14: 00007ffc40b60ba0 R15: 00007ffc40b60b7c 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:ffffc90002b9f528 EFLAGS: 00010207 RAX: dffffc0000000000 RBX: ffff88801c69da80 RCX: 1ffff110031624e0 RDX: 000000000000000f RSI: 0000000000000a20 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000140 R09: ffffffff8aec0df3 R10: fffffbfff15d81be R11: 3e4b5341542f3c20 R12: 0000000000000a20 R13: ffff88801c69da90 R14: 000000000000007e R15: ffffc90002b9f5c8 FS: 0000555555dbf300(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcce82e02a4 CR3: 00000000764f1000 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