bisecting fixing commit since ddef1e8e3f6eb26034833b7255e3fa584d54a230 building syzkaller on 5ea87a6638e52a94361b26b8576a1605585815fb testing commit ddef1e8e3f6eb26034833b7255e3fa584d54a230 with gcc (GCC) 8.1.0 kernel signature: 28b883082d58bcc7e5a1f7bb5282f459dd054c5fa914583b1289e157dcdf98c4 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: kernel BUG at ./include/linux/mm.h:LINE! run #3: crashed: kernel BUG at ./include/linux/mm.h:LINE! 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 testing current HEAD e0f8b8a65a473a8baa439cf865a694bbeb83fe90 testing commit e0f8b8a65a473a8baa439cf865a694bbeb83fe90 with gcc (GCC) 8.1.0 kernel signature: ace0ffb9ee9a5bb2250c6674564cc49e8fa2073c4a48a597a54762ff4b862db3 all runs: crashed: general protection fault in do_blockdev_direct_IO revisions tested: 2, total time: 22m54.035566074s (build: 16m23.105966834s, test: 6m8.176380097s) the crash still happens on HEAD commit msg: Linux 4.14.170 crash: general protection fault in do_blockdev_direct_IO IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready device hsr_slave_0 entered promiscuous mode device hsr_slave_1 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 Modules linked in: kasan: CONFIG_KASAN_INLINE enabled CPU: 0 PID: 7147 Comm: syz-executor.3 Not tainted 4.14.170-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff88809faa4240 task.stack: ffff888095240000 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:ffff888095247490 EFLAGS: 00010202 kasan: GPF could be caused by NULL-ptr deref or user memory access RAX: 0000000000000004 RBX: ffffea00023c241c RCX: 000000000000000c RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000020 RBP: ffff8880952477a0 R08: 0000000000000000 R09: ffff8880999e67c0 R10: ffffed101333cd08 R11: 0000000000000000 R12: dffffc0000000000 R13: 0000000000000000 R14: ffffea00023c2400 R15: ffff88809f297a40 FS: 00007f60d2f92700(0000) GS:ffff8880aee00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000758080 CR3: 0000000071131000 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/0x1b00 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+0x279/0xe70 fs/ext4/file.c:268 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:00007f60d2f91c78 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: 00007f60d2f926d4 R13: 00000000004c9c8b R14: 00000000004e0af8 R15: 00000000ffffffff Code: ff ff 48 8b bc 24 e0 00 00 00 48 c7 c6 00 85 94 86 e8 24 fb 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: ffff888095247490 RIP: compound_head include/linux/page-flags.h:147 [inline] RSP: ffff888095247490 RIP: get_page include/linux/mm.h:828 [inline] RSP: ffff888095247490 RIP: submit_page_section fs/direct-io.c:890 [inline] RSP: ffff888095247490 RIP: do_direct_IO fs/direct-io.c:1097 [inline] RSP: ffff888095247490 RIP: do_blockdev_direct_IO+0x18f1/0x6be0 fs/direct-io.c:1336 RSP: ffff888095247490 general protection fault: 0000 [#2] PREEMPT SMP KASAN ---[ end trace 84135ccf8d3efec4 ]--- Modules linked in: CPU: 1 PID: 7149 Comm: syz-executor.2 Tainted: G D 4.14.170-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff88809fb20040 task.stack: ffff888090ae8000 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:ffff888090aef490 EFLAGS: 00010202