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KCSAN: data-race in __ext4_new_inode / _find_next_bit.constprop.0

Status: auto-closed as invalid on 2020/07/23 12:47
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+f7a3e358de2cbccfe4b4@syzkaller.appspotmail.com
First crash: 1531d, last: 1405d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __ext4_new_inode / _find_next_bit.constprop.0

write to 0xffff8881257283e0 of 8 bytes by task 14514 on cpu 1:
 instrument_write include/linux/instrumented.h:42 [inline]
 __test_and_set_bit include/asm-generic/bitops/instrumented-non-atomic.h:71 [inline]
 __test_and_set_bit_le include/asm-generic/bitops/le.h:90 [inline]
 __ext4_new_inode+0xf4d/0x3020 fs/ext4/ialloc.c:957
 ext4_symlink+0x322/0x9e0 fs/ext4/namei.c:3295
 vfs_symlink fs/namei.c:3937 [inline]
 vfs_symlink+0x216/0x330 fs/namei.c:3923
 do_symlinkat+0x1ac/0x1e0 fs/namei.c:3964
 __do_sys_symlink fs/namei.c:3983 [inline]
 __se_sys_symlink fs/namei.c:3981 [inline]
 __x64_sys_symlink+0x3c/0x50 fs/namei.c:3981
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8881257283e0 of 8 bytes by task 9071 on cpu 0:
 _find_next_bit.constprop.0+0x61/0x160 lib/find_bit.c:39
 find_next_zero_bit+0x35/0x50 lib/find_bit.c:87
 find_next_zero_bit_le include/asm-generic/bitops/le.h:15 [inline]
 find_inode_bit.isra.0+0xa1/0x330 fs/ext4/ialloc.c:718
 __ext4_new_inode+0xd7b/0x3020 fs/ext4/ialloc.c:927
 ext4_mkdir+0x271/0x850 fs/ext4/namei.c:2790
 vfs_mkdir+0x281/0x3b0 fs/namei.c:3625
 do_mkdirat+0x1b5/0x200 fs/namei.c:3648
 __do_sys_mkdir fs/namei.c:3664 [inline]
 __se_sys_mkdir fs/namei.c:3662 [inline]
 __x64_sys_mkdir+0x3d/0x50 fs/namei.c:3662
 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: 9071 Comm: syz-executor.1 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (215):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/06/18 12:41 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 3ea11d3f .config console log report ci2-upstream-kcsan-gce
2020/06/17 23:26 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 d45a4d69 .config console log report ci2-upstream-kcsan-gce
2020/06/17 11:14 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 b6c46f43 .config console log report ci2-upstream-kcsan-gce
2020/06/16 23:00 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 b9f3810b .config console log report ci2-upstream-kcsan-gce
2020/06/16 11:00 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 4ea9d964 .config console log report ci2-upstream-kcsan-gce
2020/06/15 20:15 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 baca2611 .config console log report ci2-upstream-kcsan-gce
2020/06/15 08:08 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 8e3ab941 .config console log report ci2-upstream-kcsan-gce
2020/06/14 11:18 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 2a22c77a .config console log report ci2-upstream-kcsan-gce
2020/06/13 23:13 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 a61674a5 .config console log report ci2-upstream-kcsan-gce
2020/06/13 11:12 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 dbce178a .config console log report ci2-upstream-kcsan-gce
2020/06/13 04:52 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 f4724dd3 .config console log report ci2-upstream-kcsan-gce
2020/06/12 04:26 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 819b58b0 .config console log report ci2-upstream-kcsan-gce
2020/06/11 16:10 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 1beaee21 .config console log report ci2-upstream-kcsan-gce
2020/06/11 00:38 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 3ab7a05a .config console log report ci2-upstream-kcsan-gce
2020/06/10 12:47 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 5caaad3a .config console log report ci2-upstream-kcsan-gce
2020/06/10 00:33 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 860c4de9 .config console log report ci2-upstream-kcsan-gce
2020/06/09 12:18 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 092934c1 .config console log report ci2-upstream-kcsan-gce
2020/06/08 23:47 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 0d60b78a .config console log report ci2-upstream-kcsan-gce
2020/06/08 10:40 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 7604bb03 .config console log report ci2-upstream-kcsan-gce
2020/06/07 20:59 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 7751efd0 .config console log report ci2-upstream-kcsan-gce
2020/06/07 09:03 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 2c2b926c .config console log report ci2-upstream-kcsan-gce
2020/06/06 13:18 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 e6b89e4e .config console log report ci2-upstream-kcsan-gce
2020/06/06 01:51 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 c3e9afb3 .config console log report ci2-upstream-kcsan-gce
2020/06/05 13:35 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 d36418e9 .config console log report ci2-upstream-kcsan-gce
2020/06/05 01:13 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 2420d1bc .config console log report ci2-upstream-kcsan-gce
2020/06/04 13:11 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 6720fdef .config console log report ci2-upstream-kcsan-gce
2020/06/04 13:09 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 6720fdef .config console log report ci2-upstream-kcsan-gce
2020/06/04 01:11 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 b0d1c0d5 .config console log report ci2-upstream-kcsan-gce
2020/06/03 12:43 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 a5ce5de0 .config console log report ci2-upstream-kcsan-gce
2020/06/03 00:50 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 f3ba1b5b .config console log report ci2-upstream-kcsan-gce
2020/06/02 12:31 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 52fd7b7d .config console log report ci2-upstream-kcsan-gce
2020/05/31 08:40 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 a0331e89 .config console log report ci2-upstream-kcsan-gce
2020/05/30 14:47 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 6f3e1c7c .config console log report ci2-upstream-kcsan-gce
2020/05/30 03:02 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 954bd312 .config console log report ci2-upstream-kcsan-gce
2020/05/29 13:57 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 bed08304 .config console log report ci2-upstream-kcsan-gce
2020/05/29 00:42 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 d19ed305 .config console log report ci2-upstream-kcsan-gce
2020/05/28 12:22 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 c7192a2f .config console log report ci2-upstream-kcsan-gce
2020/05/26 17:11 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 9072c126 .config console log report ci2-upstream-kcsan-gce
2020/05/26 02:01 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 8ca3b7d2 .config console log report ci2-upstream-kcsan-gce
2020/05/25 12:37 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 73964a9b .config console log report ci2-upstream-kcsan-gce
2020/05/25 00:41 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 11284182 .config console log report ci2-upstream-kcsan-gce
2020/05/24 12:38 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 ce7ca010 .config console log report ci2-upstream-kcsan-gce
2020/05/23 22:33 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 96c92ad3 .config console log report ci2-upstream-kcsan-gce
2020/05/22 17:37 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 4afdfa20 .config console log report ci2-upstream-kcsan-gce
2020/03/13 19:20 https://github.com/google/ktsan.git kcsan 941e0d917bbf 749688d2 .config console log report ci2-upstream-kcsan-gce
2020/03/13 07:19 https://github.com/google/ktsan.git kcsan 941e0d917bbf fd69032d .config console log report ci2-upstream-kcsan-gce
2020/02/14 01:35 https://github.com/google/ktsan.git kcsan b12d66a6c34f 5d7b90f1 .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.