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KCSAN: data-race in ext4_itable_unused_count / ext4_itable_unused_set

Status: auto-closed as invalid on 2020/04/07 17:45
Subsystems: ext4
[Documentation on labels]
First crash: 1620d, last: 1548d
▶ ▼ Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in ext4_itable_unused_count / ext4_itable_unused_set (4) ext4 1 1000d 1000d 0/26 auto-closed as invalid on 2021/09/02 19:43
upstream KCSAN: data-race in ext4_itable_unused_count / ext4_itable_unused_set (3) ext4 1 1049d 1049d 0/26 auto-closed as invalid on 2021/07/15 18:08
upstream KCSAN: data-race in ext4_itable_unused_count / ext4_itable_unused_set (2) ext4 1 1185d 1185d 0/26 auto-closed as invalid on 2021/03/01 14:28

Sample crash report:
==================================================================
BUG: KCSAN: data-race in ext4_itable_unused_count / ext4_itable_unused_set

read to 0xffff88812c13705c of 2 bytes by task 10022 on cpu 0:
 ext4_itable_unused_count+0x26/0x90 fs/ext4/super.c:278
 __ext4_get_inode_loc+0x7ee/0x960 fs/ext4/inode.c:4321
 ext4_get_inode_loc+0x3f/0x50 fs/ext4/inode.c:4355
 ext4_reserve_inode_write+0x7f/0x150 fs/ext4/inode.c:5566
 ext4_mark_inode_dirty+0x7f/0x420 fs/ext4/inode.c:5732
 ext4_ext_tree_init+0x92/0xb0 fs/ext4/extents.c:872
 __ext4_new_inode+0x2d94/0x2f10 fs/ext4/ialloc.c:1164
 ext4_symlink+0x31c/0x9b0 fs/ext4/namei.c:3275
 vfs_symlink fs/namei.c:4131 [inline]
 vfs_symlink+0x218/0x310 fs/namei.c:4117
 do_symlinkat+0x1a5/0x1e0 fs/namei.c:4158
 __do_sys_symlink fs/namei.c:4177 [inline]
 __se_sys_symlink fs/namei.c:4175 [inline]
 __x64_sys_symlink+0x3f/0x50 fs/namei.c:4175
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff88812c13705c of 2 bytes by task 10023 on cpu 1:
 ext4_itable_unused_set+0x29/0x90 fs/ext4/super.c:334
 __ext4_new_inode+0x2894/0x2f10 fs/ext4/ialloc.c:1041
 ext4_symlink+0x31c/0x9b0 fs/ext4/namei.c:3275
 vfs_symlink fs/namei.c:4131 [inline]
 vfs_symlink+0x218/0x310 fs/namei.c:4117
 do_symlinkat+0x1a5/0x1e0 fs/namei.c:4158
 __do_sys_symlink fs/namei.c:4177 [inline]
 __se_sys_symlink fs/namei.c:4175 [inline]
 __x64_sys_symlink+0x3f/0x50 fs/namei.c:4175
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 10023 Comm: syz-executor.0 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/01/28 17:38 https://github.com/google/ktsan.git kcsan 245a43005292 c8e81ce4 .config console log report ci2-upstream-kcsan-gce
2020/01/19 20:26 https://github.com/google/ktsan.git kcsan 245a43005292 0342f8c7 .config console log report ci2-upstream-kcsan-gce
2019/12/12 10:40 https://github.com/google/ktsan.git kcsan ef798c30ba4e d973f528 .config console log report ci2-upstream-kcsan-gce
2019/11/17 03:01 https://github.com/google/ktsan.git kcsan 5863cc791e4c cdac920b .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.