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KCSAN: data-race in copy_creds / usbdev_open

Status: closed as invalid on 2019/11/19 14:44
Subsystems: usb
[Documentation on labels]
First crash: 1628d, last: 1628d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in copy_creds / usbdev_open

write to 0xffff8880a62e7818 of 4 bytes by task 7865 on cpu 1:
 get_cred include/linux/cred.h:253 [inline]
 usbdev_open+0x3ae/0x4e0 drivers/usb/core/devio.c:1026
 chrdev_open+0x150/0x380 fs/char_dev.c:414
 do_dentry_open+0x2f4/0x8f0 fs/open.c:797
 vfs_open+0x62/0x80 fs/open.c:914
 do_last fs/namei.c:3408 [inline]
 path_openat+0xf73/0x36e0 fs/namei.c:3525
 do_filp_open+0x11e/0x1b0 fs/namei.c:3555
 do_sys_open+0x3b3/0x4f0 fs/open.c:1097
 __do_sys_open fs/open.c:1115 [inline]
 __se_sys_open fs/open.c:1110 [inline]
 __x64_sys_open+0x55/0x70 fs/open.c:1110
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff8880a62e7818 of 4 bytes by task 7798 on cpu 0:
 get_cred include/linux/cred.h:253 [inline]
 copy_creds+0x258/0x340 kernel/cred.c:346
 copy_process+0x926/0x3b50 kernel/fork.c:1884
 _do_fork+0xfe/0x6e0 kernel/fork.c:2366
 __do_sys_clone kernel/fork.c:2521 [inline]
 __se_sys_clone kernel/fork.c:2502 [inline]
 __x64_sys_clone+0x12b/0x160 kernel/fork.c:2502
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7798 Comm: syz-executor.4 Not tainted 5.4.0-rc6+ #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
2019/11/09 22:10 https://github.com/google/ktsan.git kcsan 94c006602e13 1e35461e .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.