KCSAN: data-race in kernfs_refresh_inode / privileged_wrt_inode

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in kernfs_refresh_inode / privileged_wrt_inode_uidgid kernfs				2	1630d	1634d	0/26	closed as invalid on 2019/11/19 13:24

================================================================== BUG: KCSAN: data-race in kernfs_refresh_inode / privileged_wrt_inode_uidgid read to 0xffff888128c44ae8 of 4 bytes by task 3988 on cpu 0: privileged_wrt_inode_uidgid+0x59/0x90 kernel/capability.c:489 capable_wrt_inode_uidgid+0x93/0xa0 kernel/capability.c:506 generic_permission fs/namei.c:346 [inline] generic_permission+0x2b0/0x410 fs/namei.c:332 kernfs_iop_permission+0x7d/0xa0 fs/kernfs/inode.c:286 do_inode_permission fs/namei.c:384 [inline] inode_permission+0x241/0x370 fs/namei.c:449 may_lookup fs/namei.c:1696 [inline] link_path_walk.part.0+0x622/0xa90 fs/namei.c:2071 link_path_walk fs/namei.c:2256 [inline] path_lookupat.isra.0+0x77/0x5a0 fs/namei.c:2304 filename_lookup+0x145/0x2b0 fs/namei.c:2335 user_path_at_empty+0x4c/0x70 fs/namei.c:2615 do_readlinkat+0x84/0x220 fs/stat.c:399 __do_sys_readlink fs/stat.c:432 [inline] __se_sys_readlink fs/stat.c:429 [inline] __x64_sys_readlink+0x51/0x70 fs/stat.c:429 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x44/0xa9 write to 0xffff888128c44ae8 of 4 bytes by task 29263 on cpu 1: set_inode_attr fs/kernfs/inode.c:162 [inline] kernfs_refresh_inode+0x7a/0x140 fs/kernfs/inode.c:178 kernfs_iop_permission+0x66/0xa0 fs/kernfs/inode.c:283 do_inode_permission fs/namei.c:384 [inline] inode_permission+0x241/0x370 fs/namei.c:449 may_lookup fs/namei.c:1696 [inline] link_path_walk.part.0+0x622/0xa90 fs/namei.c:2071 link_path_walk fs/namei.c:2256 [inline] path_lookupat.isra.0+0x77/0x5a0 fs/namei.c:2304 filename_lookup+0x145/0x2b0 fs/namei.c:2335 user_path_at_empty+0x4c/0x70 fs/namei.c:2615 do_readlinkat+0x84/0x220 fs/stat.c:399 __do_sys_readlink fs/stat.c:432 [inline] __se_sys_readlink fs/stat.c:429 [inline] __x64_sys_readlink+0x51/0x70 fs/stat.c:429 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: 29263 Comm: udevd Not tainted 5.5.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================