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KCSAN: data-race in ovl_write_iter / privileged_wrt_inode_uidgid

Status: auto-closed as invalid on 2020/03/08 11:54
Subsystems: lsm
[Documentation on labels]
First crash: 1579d, last: 1579d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in ovl_write_iter / privileged_wrt_inode_uidgid

read to 0xffff888128dd7ac8 of 4 bytes by task 27543 on cpu 0:
 privileged_wrt_inode_uidgid+0x59/0x90 kernel/capability.c:489
 capable_wrt_inode_uidgid+0x93/0xa0 kernel/capability.c:506
 cap_convert_nscap+0x1b9/0x360 security/commoncap.c:492
 setxattr+0x2df/0x340 fs/xattr.c:444
 path_setxattr+0x12c/0x150 fs/xattr.c:470
 __do_sys_lsetxattr fs/xattr.c:492 [inline]
 __se_sys_lsetxattr fs/xattr.c:488 [inline]
 __x64_sys_lsetxattr+0x73/0x90 fs/xattr.c:488
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff888128dd7ac8 of 4 bytes by task 27546 on cpu 1:
 ovl_copyattr fs/overlayfs/overlayfs.h:384 [inline]
 ovl_write_iter+0xfc/0x550 fs/overlayfs/file.c:267
 call_write_iter include/linux/fs.h:1902 [inline]
 new_sync_write+0x388/0x4a0 fs/read_write.c:483
 __vfs_write+0xb1/0xc0 fs/read_write.c:496
 vfs_write fs/read_write.c:558 [inline]
 vfs_write+0x18a/0x390 fs/read_write.c:542
 ksys_write+0xd5/0x1b0 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x4c/0x60 fs/read_write.c:620
 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: 27546 Comm: syz-executor.4 Not tainted 5.5.0-rc1-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
2019/12/29 11:45 https://github.com/google/ktsan.git kcsan 245a43005292 af6b8ef8 .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.