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KCSAN: data-race in file_remove_privs / generic_file_splice_read

Status: auto-closed as invalid on 2020/08/13 12:27
Subsystems: fs
[Documentation on labels]
First crash: 1385d, last: 1385d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in file_remove_privs / generic_file_splice_read (2) fs 1 1085d 1085d 0/26 auto-closed as invalid on 2021/06/09 14:16

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

write to 0xffff8880986fc17c of 4 bytes by task 21171 on cpu 1:
 inode_has_no_xattr include/linux/fs.h:3573 [inline]
 file_remove_privs+0x2e0/0x370 fs/inode.c:1943
 __generic_file_write_iter+0xda/0x330 mm/filemap.c:3374
 generic_file_write_iter+0x2f3/0x3e0 mm/filemap.c:3460
 call_write_iter include/linux/fs.h:1907 [inline]
 new_sync_write fs/read_write.c:484 [inline]
 __vfs_write+0x2d8/0x340 fs/read_write.c:497
 vfs_write+0x19b/0x350 fs/read_write.c:559
 ksys_write+0xce/0x180 fs/read_write.c:612
 __do_sys_write fs/read_write.c:624 [inline]
 __se_sys_write fs/read_write.c:621 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:621
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880986fc17c of 4 bytes by task 21166 on cpu 0:
 iocb_flags include/linux/fs.h:3432 [inline]
 init_sync_kiocb include/linux/fs.h:2080 [inline]
 generic_file_splice_read+0xe5/0x310 fs/splice.c:310
 do_splice_to fs/splice.c:870 [inline]
 splice_direct_to_actor+0x2a8/0x660 fs/splice.c:950
 do_splice_direct+0xf2/0x170 fs/splice.c:1059
 do_sendfile+0x562/0xb10 fs/read_write.c:1521
 __do_sys_sendfile64 fs/read_write.c:1576 [inline]
 __se_sys_sendfile64 fs/read_write.c:1568 [inline]
 __x64_sys_sendfile64+0xa9/0x130 fs/read_write.c:1568
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 21166 Comm: syz-executor.0 Not tainted 5.8.0-rc4-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
2020/07/09 12:21 upstream 0bddd227f3dc bc238812 .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.