general protection fault in ext4_writepages

Status: fixed on 2019/12/13 00:31
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+9567fda428fba259deba@syzkaller.appspotmail.com
Fix commit: 4d06bfb97ecb ext4: Add error handling for io_end_vec struct allocation
First crash: 2454d, last: 2441d
Cause bisection: introduced by (bisect log) :
commit c8cc88163f40df39e50cda63ac361631864b453e
Author: Ritesh Harjani <riteshh@linux.ibm.com>
Date: Wed Oct 16 07:37:10 2019 +0000

  ext4: Add support for blocksize < pagesize in dioread_nolock

Crash: general protection fault in ext4_writepages (log)
Repro: C syz .config
  
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
general protection fault in ext4_writepages 4 (6) 2019/11/19 03:16
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2019/11/11 18:24 18m tytso@mit.edu https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git test OK

Sample crash report:
RDX: 0000000000000000 RSI: 0000000100000003 RDI: 0000000000000003
RBP: 0000000000000004 R08: 0000000000000001 R09: 00007fffd7a50033
R10: 0000000028120001 R11: 0000000000000246 R12: 0000000000401ef0
R13: 0000000000401f80 R14: 0000000000000000 R15: 0000000000000000
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
CPU: 0 PID: 8639 Comm: syz-executor031 Not tainted 5.4.0-rc6-next-20191106 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:mpage_map_and_submit_extent fs/ext4/inode.c:2557 [inline]
RIP: 0010:ext4_writepages+0x17b4/0x2e80 fs/ext4/inode.c:2911
Code: ff ff e8 1f cf b0 ff 48 8b 85 30 fe ff ff 48 8b 8d 00 fe ff ff 48 8d 78 10 48 89 fa 48 c1 ea 03 0f b6 89 c2 00 00 00 48 d3 e3 <42> 80 3c 2a 00 0f 85 03 16 00 00 48 89 58 10 48 c7 c0 08 ad c4 89
RSP: 0018:ffff88808bf77890 EFLAGS: 00010206
RAX: fffffffffffffff4 RBX: 00000000007ff000 RCX: 000000000000000c
RDX: 0000000000000000 RSI: ffffffff820534cd RDI: 0000000000000004
RBP: ffff88808bf77ac0 R08: 0000000000000000 R09: ffffed1015d06b7d
R10: ffffed1015d06b7c R11: ffff8880ae835be3 R12: 0000000000000000
R13: dffffc0000000000 R14: 00000000000007ff R15: ffff888086499488
FS:  0000000001162880(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000009366b000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ? 0xffffffff81000000
 do_writepages+0xfa/0x2a0 mm/page-writeback.c:2344
 __filemap_fdatawrite_range+0x2bc/0x3b0 mm/filemap.c:421
 filemap_write_and_wait_range mm/filemap.c:681 [inline]
 filemap_write_and_wait_range+0xfc/0x1d0 mm/filemap.c:675
 ext4_punch_hole+0x27d/0x1320 fs/ext4/inode.c:4314
 ext4_fallocate+0x419/0x2470 fs/ext4/extents.c:4889
 vfs_fallocate+0x4aa/0xa50 fs/open.c:309
 ksys_fallocate+0x58/0xa0 fs/open.c:332
 __do_sys_fallocate fs/open.c:340 [inline]
 __se_sys_fallocate fs/open.c:338 [inline]
 __x64_sys_fallocate+0x97/0xf0 fs/open.c:338
 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440609
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 5b 14 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fffd7a50c58 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007fffd7a50c60 RCX: 0000000000440609
RDX: 0000000000000000 RSI: 0000000100000003 RDI: 0000000000000003
RBP: 0000000000000004 R08: 0000000000000001 R09: 00007fffd7a50033
R10: 0000000028120001 R11: 0000000000000246 R12: 0000000000401ef0
R13: 0000000000401f80 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace 0ee46d2ea32148f5 ]---
RIP: 0010:mpage_map_and_submit_extent fs/ext4/inode.c:2557 [inline]
RIP: 0010:ext4_writepages+0x17b4/0x2e80 fs/ext4/inode.c:2911
Code: ff ff e8 1f cf b0 ff 48 8b 85 30 fe ff ff 48 8b 8d 00 fe ff ff 48 8d 78 10 48 89 fa 48 c1 ea 03 0f b6 89 c2 00 00 00 48 d3 e3 <42> 80 3c 2a 00 0f 85 03 16 00 00 48 89 58 10 48 c7 c0 08 ad c4 89
RSP: 0018:ffff88808bf77890 EFLAGS: 00010206
RAX: fffffffffffffff4 RBX: 00000000007ff000 RCX: 000000000000000c
RDX: 0000000000000000 RSI: ffffffff820534cd RDI: 0000000000000004
RBP: ffff88808bf77ac0 R08: 0000000000000000 R09: ffffed1015d06b7d
R10: ffffed1015d06b7c R11: ffff8880ae835be3 R12: 0000000000000000
R13: dffffc0000000000 R14: 00000000000007ff R15: ffff888086499488
FS:  0000000001162880(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000009366b000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (18):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/11/06 23:09 linux-next dcd34bd23418 da505f84 .config console log report syz C ci-upstream-linux-next-kasan-gce-root
2019/11/19 16:13 linux-next 5a6fcbeabe3e 5bc70212 .config console log report ci-upstream-linux-next-kasan-gce-root
2019/11/17 06:26 linux-next 5a6fcbeabe3e d5696d51 .config console log report ci-upstream-linux-next-kasan-gce-root
2019/11/16 10:16 linux-next 5a6fcbeabe3e cdac920b .config console log report ci-upstream-linux-next-kasan-gce-root
2019/11/16 08:11 linux-next 5a6fcbeabe3e cdac920b .config console log report ci-upstream-linux-next-kasan-gce-root
2019/11/16 01:49 linux-next 5a6fcbeabe3e cdac920b .config console log report ci-upstream-linux-next-kasan-gce-root
2019/11/15 07:42 linux-next 4e8f108c3af2 a24fe792 .config console log report ci-upstream-linux-next-kasan-gce-root
2019/11/12 05:00 linux-next 6980b7f6f9db 048f2d49 .config console log report ci-upstream-linux-next-kasan-gce-root
2019/11/11 00:16 linux-next 5591cf003452 dc438b91 .config console log report ci-upstream-linux-next-kasan-gce-root
2019/11/10 22:47 linux-next 5591cf003452 dc438b91 .config console log report ci-upstream-linux-next-kasan-gce-root
2019/11/10 18:06 linux-next 5591cf003452 dc438b91 .config console log report ci-upstream-linux-next-kasan-gce-root
2019/11/09 22:25 linux-next 5591cf003452 dc438b91 .config console log report ci-upstream-linux-next-kasan-gce-root
2019/11/09 17:06 linux-next 5591cf003452 dc438b91 .config console log report ci-upstream-linux-next-kasan-gce-root
2019/11/08 21:33 linux-next 5591cf003452 1e35461e .config console log report ci-upstream-linux-next-kasan-gce-root
2019/11/08 20:41 linux-next 5591cf003452 1e35461e .config console log report ci-upstream-linux-next-kasan-gce-root
2019/11/08 15:51 linux-next 5591cf003452 1e35461e .config console log report ci-upstream-linux-next-kasan-gce-root
2019/11/08 04:56 linux-next c68c5373c504 f39aff9e .config console log report ci-upstream-linux-next-kasan-gce-root
2019/11/06 22:35 linux-next dcd34bd23418 da505f84 .config console log report ci-upstream-linux-next-kasan-gce-root
* Struck through repros no longer work on HEAD.