bisecting fixing commit since daefdc9eb24bfa11ab77a4b2a9c3923f1051fe0b
building syzkaller on eff43e99da12c6de1965548a619c3013b8ee791e
testing commit daefdc9eb24bfa11ab77a4b2a9c3923f1051fe0b with gcc (GCC) 8.4.1 20210217
kernel signature: 145a7b10b84abfa92c55c3c146132e3607abae1ca8800636a70bd0fc3dbec6db
run #0: crashed: general protection fault in mount_fs
run #1: crashed: general protection fault in mount_fs
run #2: crashed: general protection fault in mount_fs
run #3: crashed: general protection fault in mount_fs
run #4: crashed: general protection fault in corrupted
run #5: crashed: general protection fault in mount_fs
run #6: crashed: general protection fault in mount_fs
run #7: crashed: general protection fault in mount_fs
run #8: crashed: general protection fault in mount_fs
run #9: crashed: general protection fault in corrupted
run #10: crashed: general protection fault in corrupted
run #11: crashed: general protection fault in mount_fs
run #12: crashed: general protection fault in mount_fs
run #13: crashed: general protection fault in mount_fs
run #14: crashed: general protection fault in mount_fs
run #15: crashed: general protection fault in mount_fs
run #16: crashed: general protection fault in mount_fs
run #17: crashed: general protection fault in mount_fs
run #18: crashed: general protection fault in corrupted
run #19: crashed: general protection fault in mount_fs
testing current HEAD 1722257b8ececec9b3b83a8b14058f8209d78071
testing commit 1722257b8ececec9b3b83a8b14058f8209d78071 with gcc (GCC) 8.4.1 20210217
kernel signature: 48f74d693fe25891aeb936e027b21feea02ca7e6ca5efe2bfa3379753536a375
run #0: crashed: general protection fault in mount_fs
run #1: crashed: general protection fault in mount_fs
run #2: crashed: general protection fault in mount_fs
run #3: crashed: general protection fault in mount_fs
run #4: crashed: general protection fault in mount_fs
run #5: crashed: general protection fault in corrupted
run #6: crashed: general protection fault in mount_fs
run #7: crashed: general protection fault in mount_fs
run #8: crashed: general protection fault in corrupted
run #9: crashed: general protection fault in mount_fs
revisions tested: 2, total time: 31m12.92430342s (build: 22m59.399987727s, test: 7m24.549346992s)
the crash still happens on HEAD
commit msg: Linux 4.19.193
crash: general protection fault in mount_fs
 ext4_mount+0x10/0x20 fs/ext4/super.c:6046
 mount_fs+0x7f/0x2b0 fs/super.c:1261
 vfs_kern_mount.part.11+0x58/0x3d0 fs/namespace.c:961
 vfs_kern_mount fs/namespace.c:951 [inline]
 do_new_mount fs/namespace.c:2469 [inline]
 do_mount+0x376/0x2710 fs/namespace.c:2799
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 10333 Comm: syz-executor.1 Not tainted 4.19.193-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ksys_mount+0xb1/0xd0 fs/namespace.c:3015
RIP: 0010:mount_fs+0xa9/0x2b0 fs/super.c:1266
 __do_sys_mount fs/namespace.c:3029 [inline]
 __se_sys_mount fs/namespace.c:3026 [inline]
 __x64_sys_mount+0xb9/0x150 fs/namespace.c:3026
Code: 4d 89 f0 48 3d 00 f0 ff ff 49 89 c5 0f 87 38 01 00 00 48 8d b8 c8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 b5 01 00 00 49 8b 9d c8 00 00 00 48 85 db 0f 84
 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293
RSP: 0018:ffff88808dacfcb0 EFLAGS: 00010202
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RAX: dffffc0000000000 RBX: ffff8880af31e000 RCX: 1ffff11014be2db5
RIP: 0033:0x466daa
RDX: 0000000000000019 RSI: ffff8880a5f16d88 RDI: 00000000000000c8
Code: 48 c7 c2 bc ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 b8 04 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RBP: ffff88808dacfcf0 R08: ffff8880991dd000 R09: 0000000000000000
RSP: 002b:00007f8a8bac1fa8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff89a98300
RAX: ffffffffffffffda RBX: 0000000020000200 RCX: 0000000000466daa
R13: 0000000000000000 R14: ffff8880991dd000 R15: 0000000000000000
RDX: 0000000020000080 RSI: 0000000020000100 RDI: 00007f8a8bac2000
FS:  00007f06456f4700(0000) GS:ffff8880ba300000(0000) knlGS:0000000000000000
RBP: 00007f8a8bac2040 R08: 00007f8a8bac2040 R09: 0000000020000080
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020000080
CR2: 00007f46cdda9028 CR3: 000000009dfa3000 CR4: 00000000001406e0
R13: 0000000020000100 R14: 00007f8a8bac2000 R15: 0000000020000040
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
EXT4-fs (loop3): can't allocate buddy mem
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 vfs_kern_mount.part.11+0x58/0x3d0 fs/namespace.c:961
 vfs_kern_mount fs/namespace.c:951 [inline]
 do_new_mount fs/namespace.c:2469 [inline]
 do_mount+0x376/0x2710 fs/namespace.c:2799
EXT4-fs (loop3): failed to initialize mballoc (-12)
 ksys_mount+0xb1/0xd0 fs/namespace.c:3015
 __do_sys_mount fs/namespace.c:3029 [inline]
 __se_sys_mount fs/namespace.c:3026 [inline]
 __x64_sys_mount+0xb9/0x150 fs/namespace.c:3026
 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
EXT4-fs (loop3): mount failed
RIP: 0033:0x466daa
Code: 48 c7 c2 bc ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 b8 04 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 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:00007f06456f3fa8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000020000200 RCX: 0000000000466daa
RDX: 0000000020000080 RSI: 0000000020000100 RDI: 00007f06456f4000
RBP: 00007f06456f4040 R08: 00007f06456f4040 R09: 0000000020000080
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020000080
R13: 0000000020000100 R14: 00007f06456f4000 R15: 0000000020000040
Modules linked in:
---[ end trace 3cdebdfa07baa9b1 ]---
RIP: 0010:mount_fs+0xa9/0x2b0 fs/super.c:1266
Code: 4d 89 f0 48 3d 00 f0 ff ff 49 89 c5 0f 87 38 01 00 00 48 8d b8 c8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 b5 01 00 00 49 8b 9d c8 00 00 00 48 85 db 0f 84
RSP: 0018:ffff88808dacfcb0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff8880af31e000 RCX: 1ffff11014be2db5
RDX: 0000000000000019 RSI: ffff8880a5f16d88 RDI: 00000000000000c8
RBP: ffff88808dacfcf0 R08: ffff8880991dd000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff89a98300
R13: 0000000000000000 R14: ffff8880991dd000 R15: 0000000000000000
FS:  00007f06456f4700(0000) GS:ffff8880ba300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f46cdda9028 CR3: 000000009dfa3000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400