syzbot


KCSAN: data-race in inode_owner_or_capable / ovl_write_iter

Status: auto-closed as invalid on 2020/04/17 11:26
Subsystems: overlayfs
[Documentation on labels]
Reported-by: syzbot+14b4ad8e3072bf5b6a4e@syzkaller.appspotmail.com
First crash: 1545d, last: 1545d

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

read to 0xffff888128e7aac4 of 4 bytes by task 23474 on cpu 0:
 inode_owner_or_capable+0x5c/0x100 fs/inode.c:2075
 ovl_ioctl_set_flags+0x53/0x240 fs/overlayfs/file.c:416
 ovl_ioctl_set_fsflags fs/overlayfs/file.c:472 [inline]
 ovl_ioctl+0x121/0x2a0 fs/overlayfs/file.c:516
 vfs_ioctl fs/ioctl.c:47 [inline]
 file_ioctl fs/ioctl.c:545 [inline]
 do_vfs_ioctl+0x84f/0xcf0 fs/ioctl.c:732
 ksys_ioctl+0xbd/0xe0 fs/ioctl.c:749
 __do_sys_ioctl fs/ioctl.c:756 [inline]
 __se_sys_ioctl fs/ioctl.c:754 [inline]
 __x64_sys_ioctl+0x4c/0x60 fs/ioctl.c:754
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff888128e7aac4 of 4 bytes by task 23456 on cpu 1:
 ovl_copyattr fs/overlayfs/overlayfs.h:383 [inline]
 ovl_write_iter+0x3d5/0x550 fs/overlayfs/file.c:284
 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
 __kernel_write+0xb8/0x240 fs/read_write.c:515
 write_pipe_buf+0xb6/0xf0 fs/splice.c:809
 splice_from_pipe_feed fs/splice.c:512 [inline]
 __splice_from_pipe+0x295/0x4a0 fs/splice.c:636
 splice_from_pipe+0xbb/0x100 fs/splice.c:671
 default_file_splice_write+0x45/0x90 fs/splice.c:821
 do_splice_from fs/splice.c:863 [inline]
 direct_splice_actor+0xa0/0xc0 fs/splice.c:1037
 splice_direct_to_actor+0x22b/0x540 fs/splice.c:992
 do_splice_direct+0x161/0x1e0 fs/splice.c:1080
 do_sendfile+0x384/0x7f0 fs/read_write.c:1464
 __do_sys_sendfile64 fs/read_write.c:1519 [inline]
 __se_sys_sendfile64 fs/read_write.c:1511 [inline]
 __x64_sys_sendfile64+0xbe/0x140 fs/read_write.c:1511
 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: 23456 Comm: syz-executor.2 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
2020/02/02 15:50 https://github.com/google/ktsan.git kcsan 245a43005292 93e5e335 .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.