bisecting fixing commit since ddef1e8e3f6eb26034833b7255e3fa584d54a230 building syzkaller on 5ea87a6638e52a94361b26b8576a1605585815fb testing commit ddef1e8e3f6eb26034833b7255e3fa584d54a230 with gcc (GCC) 8.1.0 kernel signature: 4f607a4148448de14ddbf411cbf0cfd2ac2040d6a8f1cf22ff8c8776cab5ecf9 all runs: crashed: general protection fault in do_blockdev_direct_IO testing current HEAD 12cd844a39ed16aa183a820a54fe6f9a0bb4cd14 testing commit 12cd844a39ed16aa183a820a54fe6f9a0bb4cd14 with gcc (GCC) 8.1.0 kernel signature: 8df7b80fe8af27c4554c6bbce4c2abfdacfc75861c90308f08ace3744456594d all runs: crashed: general protection fault in do_blockdev_direct_IO revisions tested: 2, total time: 24m51.012021761s (build: 17m20.576467456s, test: 6m45.500055135s) the crash still happens on HEAD commit msg: Linux 4.14.173 crash: general protection fault in do_blockdev_direct_IO bridge0: port 2(bridge_slave_1) entered blocking state bridge0: port 2(bridge_slave_1) entered forwarding state device hsr_slave_0 entered promiscuous mode kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN device hsr_slave_1 entered promiscuous mode Modules linked in: CPU: 0 PID: 7042 Comm: syz-executor.2 Not tainted 4.14.173-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff88809be24440 task.stack: ffff88806efb8000 RIP: 0010:__read_once_size include/linux/compiler.h:183 [inline] RIP: 0010:compound_head include/linux/page-flags.h:147 [inline] RIP: 0010:get_page include/linux/mm.h:828 [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+0x18f1/0x6be0 fs/direct-io.c:1336 RSP: 0018:ffff88806efbf490 EFLAGS: 00010202 RAX: 0000000000000004 RBX: ffffea000261841c RCX: 000000000000000c RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000020 RBP: ffff88806efbf7a0 R08: 0000000000000000 R09: ffff8880998b1080 R10: ffffed1013316220 R11: 0000000000000000 R12: dffffc0000000000 R13: 0000000000000000 R14: ffffea0002618400 R15: ffff88807ae2ba40 FS: 00007fd1d3bd8700(0000) GS:ffff8880aee00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020788ffc CR3: 000000009bab4000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __blockdev_direct_IO+0x72/0xd9 fs/direct-io.c:1422 ext4_direct_IO_write fs/ext4/inode.c:3712 [inline] ext4_direct_IO+0x6ed/0x1b80 fs/ext4/inode.c:3848 generic_file_direct_write+0x1ee/0x410 mm/filemap.c:2950 __generic_file_write_iter+0x270/0x580 mm/filemap.c:3129 ext4_file_write_iter+0x27a/0xe40 fs/ext4/file.c:270 call_write_iter include/linux/fs.h:1777 [inline] do_iter_readv_writev+0x460/0x900 fs/read_write.c:675 do_iter_write+0x12b/0x520 fs/read_write.c:954 vfs_iter_write+0x5b/0xb0 fs/read_write.c:967 iter_file_splice_write+0x540/0xc20 fs/splice.c:749 do_splice_from fs/splice.c:851 [inline] do_splice fs/splice.c:1147 [inline] SYSC_splice fs/splice.c:1402 [inline] SyS_splice+0x6e9/0x1580 fs/splice.c:1382 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x459f49 RSP: 002b:00007fd1d3bd7c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000459f49 RDX: 0000000000000007 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 000000000075bf20 R08: 00000000ffffffff R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd1d3bd86d4 R13: 00000000004c9c8b R14: 00000000004e0af8 R15: 00000000ffffffff Code: ff ff 48 8b bc 24 e0 00 00 00 48 c7 c6 80 84 94 86 e8 a4 fa e0 ff 0f 0b 48 8b 84 24 e0 00 00 00 48 8d 78 20 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 0f 85 f3 44 00 00 48 8b 9c 24 e0 00 00 00 48 8b RIP: __read_once_size include/linux/compiler.h:183 [inline] RSP: ffff88806efbf490 RIP: compound_head include/linux/page-flags.h:147 [inline] RSP: ffff88806efbf490 RIP: get_page include/linux/mm.h:828 [inline] RSP: ffff88806efbf490 RIP: submit_page_section fs/direct-io.c:890 [inline] RSP: ffff88806efbf490 RIP: do_direct_IO fs/direct-io.c:1097 [inline] RSP: ffff88806efbf490 RIP: do_blockdev_direct_IO+0x18f1/0x6be0 fs/direct-io.c:1336 RSP: ffff88806efbf490 ---[ end trace 3e1ac697dd223b2a ]---