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KCSAN: data-race in setattr_copy / tomoyo_realpath_from_path

Status: auto-closed as invalid on 2020/09/03 17:17
Subsystems: fs
[Documentation on labels]
First crash: 1897d, last: 1897d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in setattr_copy / tomoyo_realpath_from_path

write to 0xffff88808ce0fbf0 of 2 bytes by task 19 on cpu 0:
 setattr_copy+0x19d/0x1b0 fs/attr.c:198
 shmem_setattr+0xc4/0x580 mm/shmem.c:1082
 notify_change+0x7d4/0xa20 fs/attr.c:336
 handle_remove drivers/base/devtmpfs.c:330 [inline]
 handle drivers/base/devtmpfs.c:378 [inline]
 devtmpfsd+0x87c/0x970 drivers/base/devtmpfs.c:413
 kthread+0x20d/0x230 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

read to 0xffff88808ce0fbf0 of 2 bytes by task 14160 on cpu 1:
 tomoyo_get_absolute_path security/tomoyo/realpath.c:105 [inline]
 tomoyo_realpath_from_path+0x286/0x3c0 security/tomoyo/realpath.c:276
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0xc6/0x330 security/tomoyo/file.c:822
 tomoyo_inode_getattr+0x18/0x20 security/tomoyo/tomoyo.c:123
 security_inode_getattr+0x7f/0xd0 security/security.c:1278
 vfs_getattr fs/stat.c:121 [inline]
 vfs_statx+0x118/0x2b0 fs/stat.c:206
 vfs_stat include/linux/fs.h:3297 [inline]
 __do_sys_newstat fs/stat.c:361 [inline]
 __se_sys_newstat+0x46/0x250 fs/stat.c:357
 __x64_sys_newstat+0x2d/0x40 fs/stat.c:357
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 14160 Comm: syz-executor.1 Not tainted 5.8.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/07/30 17:13 upstream 83bdc7275e62 b0947553 .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.