KCSAN: data-race in ext4_handle_inode_extension / generic_file_read_iter

Status: closed as invalid on 2020/06/18 14:24
Subsystems: ext4
[Documentation on labels]
First crash: 2415d, last: 2270d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in ext4_handle_inode_extension / generic_file_read_iter

write to 0xffff8880bb6705b8 of 8 bytes by task 20236 on cpu 1:
 i_size_write include/linux/fs.h:894 [inline]
 ext4_update_inode_size fs/ext4/ext4.h:3083 [inline]
 ext4_handle_inode_extension+0x3b4/0x580 fs/ext4/file.c:330
 ext4_dio_write_iter fs/ext4/file.c:536 [inline]
 ext4_file_write_iter+0x812/0xd30 fs/ext4/file.c:640
 call_write_iter include/linux/fs.h:1907 [inline]
 do_iter_readv_writev+0x4a7/0x5d0 fs/read_write.c:694
 do_iter_write fs/read_write.c:999 [inline]
 do_iter_write+0x137/0x3a0 fs/read_write.c:980
 vfs_iter_write+0x56/0x80 fs/read_write.c:1040
 iter_file_splice_write+0x530/0x830 fs/splice.c:760
 do_splice_from fs/splice.c:863 [inline]
 direct_splice_actor+0x97/0xb0 fs/splice.c:1037
 splice_direct_to_actor+0x22f/0x540 fs/splice.c:992
 do_splice_direct+0x152/0x1d0 fs/splice.c:1080
 do_sendfile+0x380/0x800 fs/read_write.c:1521
 __do_sys_sendfile64 fs/read_write.c:1582 [inline]
 __se_sys_sendfile64 fs/read_write.c:1568 [inline]
 __x64_sys_sendfile64+0x121/0x140 fs/read_write.c:1568
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880bb6705b8 of 8 bytes by task 20232 on cpu 0:
 generic_file_buffered_read mm/filemap.c:2091 [inline]
 generic_file_read_iter+0x85b/0x18c0 mm/filemap.c:2309
 ext4_file_read_iter fs/ext4/file.c:131 [inline]
 ext4_file_read_iter+0x103/0x360 fs/ext4/file.c:114
 call_read_iter include/linux/fs.h:1901 [inline]
 generic_file_splice_read+0x2df/0x470 fs/splice.c:313
 do_splice_to+0xc7/0x100 fs/splice.c:892
 splice_direct_to_actor+0x1b9/0x540 fs/splice.c:971
 do_splice_direct+0x152/0x1d0 fs/splice.c:1080
 do_sendfile+0x380/0x800 fs/read_write.c:1521
 __do_sys_sendfile64 fs/read_write.c:1582 [inline]
 __se_sys_sendfile64 fs/read_write.c:1568 [inline]
 __x64_sys_sendfile64+0x121/0x140 fs/read_write.c:1568
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 20232 Comm: syz-executor.2 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (18):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/06/10 13:32 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 5caaad3a .config console log report ci2-upstream-kcsan-gce
2020/06/04 18:15 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 6720fdef .config console log report ci2-upstream-kcsan-gce
2020/05/29 06:23 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 d19ed305 .config console log report ci2-upstream-kcsan-gce
2020/05/25 04:19 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 11284182 .config console log report ci2-upstream-kcsan-gce
2020/05/21 09:06 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 4afdfa20 .config console log report ci2-upstream-kcsan-gce
2020/05/19 18:42 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 6d882fd2 .config console log report ci2-upstream-kcsan-gce
2020/04/28 13:19 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 e3ecea2e .config console log report ci2-upstream-kcsan-gce
2020/04/03 20:28 https://github.com/google/ktsan.git kcsan 40959e34d670 5ed396e6 .config console log report ci2-upstream-kcsan-gce
2020/03/14 15:21 https://github.com/google/ktsan.git kcsan 941e0d917bbf 749688d2 .config console log report ci2-upstream-kcsan-gce
2020/03/13 02:44 https://github.com/google/ktsan.git kcsan 941e0d917bbf d850e9d0 .config console log report ci2-upstream-kcsan-gce
2020/03/09 12:52 https://github.com/google/ktsan.git kcsan 941e0d917bbf 2e9971bb .config console log report ci2-upstream-kcsan-gce
2020/02/02 15:35 https://github.com/google/ktsan.git kcsan 245a43005292 93e5e335 .config console log report ci2-upstream-kcsan-gce
2020/02/01 23:21 https://github.com/google/ktsan.git kcsan 245a43005292 2274ad39 .config console log report ci2-upstream-kcsan-gce
2020/01/26 17:10 https://github.com/google/ktsan.git kcsan 245a43005292 dd56146d .config console log report ci2-upstream-kcsan-gce
2020/01/24 16:18 https://github.com/google/ktsan.git kcsan 245a43005292 2e95ab33 .config console log report ci2-upstream-kcsan-gce
2020/01/23 17:15 https://github.com/google/ktsan.git kcsan 245a43005292 11ebf937 .config console log report ci2-upstream-kcsan-gce
2020/01/20 17:32 https://github.com/google/ktsan.git kcsan 245a43005292 c40da18c .config console log report ci2-upstream-kcsan-gce
2020/01/17 10:42 https://github.com/google/ktsan.git kcsan 245a43005292 3de7aabb .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.