bisecting fixing commit since c3038e718a19fc596f7b1baba0f83d5146dc7784 building syzkaller on d01bb02a96019cda0fa8c46e5c6d5eb66a273f17 testing commit c3038e718a19fc596f7b1baba0f83d5146dc7784 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 2a4a7573d86a5551cb3fe78a407124ed11c9a0312acf6f4f89334453729913f3 run #0: crashed: general protection fault in do_blockdev_direct_IO run #1: crashed: general protection fault in do_blockdev_direct_IO run #2: crashed: general protection fault in do_blockdev_direct_IO run #3: crashed: general protection fault in do_blockdev_direct_IO run #4: crashed: general protection fault in do_blockdev_direct_IO run #5: crashed: kernel BUG in do_blockdev_direct_IO run #6: crashed: general protection fault in do_blockdev_direct_IO run #7: crashed: general protection fault in do_blockdev_direct_IO run #8: crashed: general protection fault in do_blockdev_direct_IO run #9: crashed: general protection fault in do_blockdev_direct_IO run #10: crashed: general protection fault in do_blockdev_direct_IO run #11: crashed: general protection fault in do_blockdev_direct_IO run #12: crashed: general protection fault in do_blockdev_direct_IO run #13: crashed: general protection fault in do_blockdev_direct_IO run #14: crashed: general protection fault in do_blockdev_direct_IO run #15: crashed: general protection fault in do_blockdev_direct_IO run #16: crashed: general protection fault in do_blockdev_direct_IO run #17: crashed: general protection fault in do_blockdev_direct_IO run #18: crashed: general protection fault in do_blockdev_direct_IO run #19: crashed: general protection fault in do_blockdev_direct_IO testing current HEAD b172b44fcb1771e083aad806fa96f3f60e2ddfac testing commit b172b44fcb1771e083aad806fa96f3f60e2ddfac compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: e99234096bd4e941ae763f9bff915cdec72d6574f4aff82ab0dddc95d4bd58d3 run #0: crashed: general protection fault in do_blockdev_direct_IO run #1: crashed: kernel BUG in do_blockdev_direct_IO run #2: crashed: general protection fault in do_blockdev_direct_IO run #3: crashed: general protection fault in do_blockdev_direct_IO run #4: crashed: general protection fault in do_blockdev_direct_IO run #5: crashed: general protection fault in do_blockdev_direct_IO run #6: crashed: general protection fault in do_blockdev_direct_IO run #7: crashed: general protection fault in do_blockdev_direct_IO run #8: crashed: general protection fault in do_blockdev_direct_IO run #9: crashed: general protection fault in do_blockdev_direct_IO revisions tested: 2, total time: 29m35.281970764s (build: 22m15.729897148s, test: 6m14.779440514s) the crash still happens on HEAD commit msg: Linux 4.19.206 crash: general protection fault in do_blockdev_direct_IO IPv6: ADDRCONF(NETDEV_UP): hsr0: link is not ready kasan: CONFIG_KASAN_INLINE enabled IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready kasan: GPF could be caused by NULL-ptr deref or user memory access IPv6: ADDRCONF(NETDEV_UP): veth1_to_hsr: link is not ready general protection fault: 0000 [#1] PREEMPT SMP KASAN IPv6: ADDRCONF(NETDEV_UP): veth0_to_hsr: link is not ready CPU: 0 PID: 6548 Comm: syz-executor.0 Not tainted 4.19.206-syzkaller #0 IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_hsr: link becomes ready Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__read_once_size include/linux/compiler.h:261 [inline] RIP: 0010:compound_head include/linux/page-flags.h:142 [inline] RIP: 0010:get_page include/linux/mm.h:931 [inline] RIP: 0010:submit_page_section fs/direct-io.c:890 [inline] RIP: 0010:do_direct_IO fs/direct-io.c:1097 [inline] RIP: 0010:do_blockdev_direct_IO+0xeb0/0x6f70 fs/direct-io.c:1333 Code: 00 00 48 c7 84 24 90 02 00 00 00 00 00 00 45 85 e4 0f 85 35 0c 00 00 48 8b 84 24 f0 00 00 00 48 8d 78 08 48 89 f8 48 c1 e8 03 <80> 3c 18 00 0f 85 ba 51 00 00 48 8b b4 24 f0 00 00 00 48 8b 46 08 RSP: 0018:ffff8881e4c9f450 EFLAGS: 00010202 RAX: 0000000000000001 RBX: dffffc0000000000 RCX: ffffffff81a557fe RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000000008 IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready RBP: ffff8881e4c9f790 R08: fffff94000f2de07 R09: fffff94000f2de06 R10: fffff94000f2de06 R11: ffffea000796f037 R12: 0000000000000000 R13: ffffea000796f000 R14: ffffea000796f034 R15: ffff8881e4507a40 FS: 00007f0fe83f9700(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8a1f527028 CR3: 00000001e45ee002 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_hsr: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_hsr: link becomes ready __blockdev_direct_IO+0x72/0xe0 fs/direct-io.c:1419 ext4_direct_IO_write fs/ext4/inode.c:3777 [inline] ext4_direct_IO+0x87f/0x17d0 fs/ext4/inode.c:3915 generic_file_direct_write+0x1ee/0x410 mm/filemap.c:3073 __generic_file_write_iter+0x279/0x590 mm/filemap.c:3252 IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready ext4_file_write_iter+0x282/0xe60 fs/ext4/file.c:272 call_write_iter include/linux/fs.h:1821 [inline] do_iter_readv_writev+0x4ae/0x960 fs/read_write.c:681 do_iter_write fs/read_write.c:960 [inline] do_iter_write+0x12a/0x510 fs/read_write.c:941 vfs_iter_write+0x5b/0xb0 fs/read_write.c:973 iter_file_splice_write+0x55d/0xc40 fs/splice.c:750 do_splice_from fs/splice.c:852 [inline] do_splice+0xa25/0x12b0 fs/splice.c:1154 __do_sys_splice fs/splice.c:1428 [inline] __se_sys_splice fs/splice.c:1408 [inline] __x64_sys_splice+0x248/0x300 fs/splice.c:1408 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x461949 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:00007f0fe83f91a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 000000000052bf00 RCX: 0000000000461949 RDX: 0000000000000007 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 0000000000000006 R08: 00000000ffffffff R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004f8f90 R14: 00000000004b50c4 R15: 00007f0fe83f96bc Modules linked in: IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready ---[ end trace d01c7c10d0337dd4 ]--- IPv6: ADDRCONF(NETDEV_UP): veth1_to_hsr: link is not ready RIP: 0010:__read_once_size include/linux/compiler.h:261 [inline] RIP: 0010:compound_head include/linux/page-flags.h:142 [inline] RIP: 0010:get_page include/linux/mm.h:931 [inline] RIP: 0010:submit_page_section fs/direct-io.c:890 [inline] RIP: 0010:do_direct_IO fs/direct-io.c:1097 [inline] RIP: 0010:do_blockdev_direct_IO+0xeb0/0x6f70 fs/direct-io.c:1333 IPv6: ADDRCONF(NETDEV_UP): hsr0: link is not ready Code: 00 00 48 c7 84 24 90 02 00 00 00 00 00 00 45 85 e4 0f 85 35 0c 00 00 48 8b 84 24 f0 00 00 00 48 8d 78 08 48 89 f8 48 c1 e8 03 <80> 3c 18 00 0f 85 ba 51 00 00 48 8b b4 24 f0 00 00 00 48 8b 46 08 IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready RSP: 0018:ffff8881e4c9f450 EFLAGS: 00010202 RAX: 0000000000000001 RBX: dffffc0000000000 RCX: ffffffff81a557fe RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000000008 RBP: ffff8881e4c9f790 R08: fffff94000f2de07 R09: fffff94000f2de06 R10: fffff94000f2de06 R11: ffffea000796f037 R12: 0000000000000000 R13: ffffea000796f000 R14: ffffea000796f034 R15: ffff8881e4507a40 FS: 00007f0fe83f9700(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8a1f52e000 CR3: 00000001e45ee002 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 00 00 add %al,(%rax) 2: 48 c7 84 24 90 02 00 movq $0x0,0x290(%rsp) 9: 00 00 00 00 00 e: 45 85 e4 test %r12d,%r12d 11: 0f 85 35 0c 00 00 jne 0xc4c 17: 48 8b 84 24 f0 00 00 mov 0xf0(%rsp),%rax 1e: 00 1f: 48 8d 78 08 lea 0x8(%rax),%rdi 23: 48 89 f8 mov %rdi,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1) <-- trapping instruction 2e: 0f 85 ba 51 00 00 jne 0x51ee 34: 48 8b b4 24 f0 00 00 mov 0xf0(%rsp),%rsi 3b: 00 3c: 48 8b 46 08 mov 0x8(%rsi),%rax