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KCSAN: data-race in file_remove_privs / selinux_mmap_file

Status: auto-closed as invalid on 2021/06/04 21:19
Subsystems: fs
[Documentation on labels]
First crash: 1091d, last: 1091d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in file_remove_privs / selinux_mmap_file

write to 0xffff88812bf2c5cc of 4 bytes by task 10922 on cpu 0:
 inode_has_no_xattr include/linux/fs.h:3653 [inline]
 file_remove_privs+0x312/0x3a0 fs/inode.c:1947
 __generic_file_write_iter+0xdd/0x300 mm/filemap.c:3718
 generic_file_write_iter+0x75/0x130 mm/filemap.c:3804
 call_write_iter include/linux/fs.h:2116 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4c0 fs/read_write.c:866
 vfs_writev fs/read_write.c:939 [inline]
 do_pwritev+0x1e5/0x3a0 fs/read_write.c:1036
 __do_sys_pwritev fs/read_write.c:1083 [inline]
 __se_sys_pwritev fs/read_write.c:1078 [inline]
 __x64_sys_pwritev+0x54/0x60 fs/read_write.c:1078
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88812bf2c5cc of 4 bytes by task 10949 on cpu 1:
 inode_has_perm security/selinux/hooks.c:1705 [inline]
 selinux_mmap_file+0x5b/0x1f0 security/selinux/hooks.c:3894
 security_mmap_file+0x106/0x160 security/security.c:1543
 vm_mmap_pgoff+0x70/0x1d0 mm/util.c:515
 ksys_mmap_pgoff+0x2a8/0x380 mm/mmap.c:1638
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 10949 Comm: syz-executor.3 Not tainted 5.12.0-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
2021/04/30 21:09 upstream 65c61de9d090 77e2b668 .config console log report info ci2-upstream-kcsan-gce KCSAN: data-race in file_remove_privs / selinux_mmap_file
* Struck through repros no longer work on HEAD.